Semiconductor-based photocatalysts for dehydrogenation reactions

Abstract

The present disclosure relates to compositions and processes for alcohol dehydrogenation or alcohol dehydrogenative coupling, amine dehydrogenative coupling, and thiol dehydrogenative coupling.

Description

Attorney Docket No. 039621.01472SEMICONDUCTOR-BASED PHOTOCATALYSTS FOR DEHYDROGENATION REACTIONSCROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to U.S. Provisional Patent Application Serial No.63 / 720,033 filed on November 13, 2024, the contents of which is incorporated herein by reference in its entirety.SUMMARY OF VARIOUS ASPECTS OF THE DISCLOSURE

[0002] A first aspect of the present disclosure is directed to a composition comprising: a) zinc indium sulfide (ZIS) nanocrystals,b) a ligand, andc) a cocatalyst.In some embodiments, the ligand is a hydrophobic surface-capping ligand, a water-soluble ligand, or an inorganic ligand. In some embodiments, the hydrophobic surface-capping ligand is oleylamine (OAm), trioctylphosphine oxide (TOPO), trioctylphosphine (TOP), oleic acid (OA), trioctylamine (TOA), tetradecylphosphonic acid (TDPA), polyvinylpyrrolidone (PVP), or a thiol. In some embodiments, the water-soluble ligand is a bifunctional thiol, an amino acid, an alcohol, or a carboxylate. In some embodiments, the inorganic ligand is hydroxide (OH), sulfide (S2'), tetrafluorob orate (BFT), thiosulfate (S2O32'), phosphate (PO '), fluoride (F‘), chloride (CF), bromide (Br), iodide (T), astatide (At"), thiocyanate (SCN‘), AcO-, CIOF, HCCh", CIO-, NO3', Se2', MoO42', or WO42'. In some embodiments, the cocatalyst is a metal cocatalyst. In some embodiments, the metal cocatalyst is Ni, Pt, Ir, Cu, Ag, Au, Co, Fe, Ru, Rh, or Pd. In some embodiments, the cocatalyst is a non-metallic cocatalyst. In some embodiments, the non- metallic cocatalyst is M0S2, M2P, NiP, C02P, CoP, FeP, MoP, M0P2, RuP, RU2P, NiCoP, or FeCoP.

[0003] A second aspect of the present disclosure is directed to a process for alcohol dehydrogenation or alcohol dehydrogenative coupling, comprising treating an alcohol with the composition and exposure to light.

[0004] A third aspect of the present disclosure is directed to a process for amine dehydrogenative coupling, comprising treating an amine with the composition and exposure to light.Attorney Docket No. 039621.01472

[0005] A fourth aspect of the present disclosure is directed to a process for thiol dehydrogenative coupling, comprising treating a thiol with the composition and exposure to light.

[0006] Presently disclosed compositions may offer several benefits in connection with switchable selectivity for sustainable chemical transformations and renewable energy conversion.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. la-FIG. 1g show the synthesis and characterization of ZIS NCs. FIG. la is a schematic showing an overview of the colloidal synthesis of ZIS NCs. FIG. lb is a TEM image of pristine ZIS NCs. FIG. 1c is a graph showing the height profiles of ZIS nanoplates. FIG. Id is a HRTEM image of ZIS NCs after ligand exchange with 3 -mercaptopropionic acid for better image quality (FFT patterns as insets). FIG. le is an enlarged image of a selected area of FIG. Id with atomic resolution. FIG. If shows the powder XRD pattern of pristine ZIS NCs and ZIS after ligand exchange with S2'. The signals align well with the standard hexagonal ZIS reference pattern (JCPDS No. 65-2023). FIG. 1g is a series of HRTEM and corresponding FFT patterns of hexagonal ZIS nanocrystals after ligand exchange.

[0008] FIG. 2a-FIG. 2d show photocatalytic methanol dehydrogenation with switchable selectivity. FIG. 2a is a graph showing switchable selectivity that was observed during methanol dehydrogenation by varying Ni2+precursor loadings over a 16 h duration in methanol solution. FIG. 2b is a graph showing reaction progress over a 22 h duration in the presence of 0.25 wt% Ni2+. FIG. 2c is a graph showing reaction progress over a 22 h duration in the presence of 3 wt% Ni2+. FIG. 2d is a graph showing a comparative analysis with other typical sulfide semiconductor materials under similar reaction conditions with 0.25 and 3 wt% Ni2+(Wang et al., Adv. Mater., 2023, 35(5):e2205782; Xie et al., Nat. Commun., 2018, 9(1)'.1181; Zhang etal., Chem. Commun., 2020, 5672 / 1776-1779). The reactions were carried out with 2 mg photocatalyst in an air-free 80% aqueous MeOH under a under a 365 nm UV light (30 mW / cm2), and the selectivity was calculated on carbon basis.

[0009] FIG. 3a-FIG. 3e show the characterization of Ni cocatalyst on ZIS. FIG. 3a depicts the band edge positions of synthesized ZIS NCs with single crystal structure of ZmIn2S4 as insets (adapted from ICSD 44637), and the photodeposition of nickel. FIG. 3b shows high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and the corresponding element mapping of the Ni / ZIS after photo-deposition, showing homogenouslyAttorney Docket No. 039621.01472dispersed Zn, In, S, and Ni. FIG. 3c is a depiction of the XPS Ni 2p spectrum of Ni / ZIS post illumination, starting with 1% NiCh 6H2O precursor. FIG. 3d is a series of XAS spectra of Ni L2,3-edge of standard dry samples (Ni foil and NiO) and a concentrated liquid sample (2% NiCh 6H2O in the dispersion of ZIS NCs in water and methanol) in TEY mode. FIG. 3e is a series of corresponding in situ XAS of the Ni L2,3-edge measured in TEY mode. The sample was prepared with 1 wt% absorbed Ni2+to observe evident changes upon light irradiation. The acquisition time of each spectrum was approximately 720 seconds, and the signal intensities were normalized without baseline treatment.

[0010] FIG. 4a-FIG. 4c show the quantification of nickel concentration and its influence on selectivity. FIG. 4a is a graph showing normalized nickel distribution after 16 h illumination upon different concentrations of Ni2+precursor. FIG. 4b is a graph showing nickel distribution for photocatalytic reaction with 3 wt% nickel over a 16 h duration. The first data point (0 h) was collected after keeping the sample in the dark for 16 hours, which represents the absorbed Ni2+. FIG. 4c is a graph showing improved selectivity upon scaling down the photocatalyst loading and absolute nickel concentration.

[0011] FIG. 5a-FIG. 5e show mechanistic studies and proposals toward switchable selectivity. FIG. 5a shows control experiments with pre-added HCHO. FIG. 5b is an illustration of pathways for the generation of EG. FIG. 5c is a series of n situ EPR spectra taken during the photocatalytic reaction in the presence of DMPO as a spin-trapping agent under light irradiation. FIG. 5d depicts reaction pathways for the generation of HCHO and EG through different radical species. FIG. 5e depicts the proposed reaction mechanism for photocatalytic methanol dehydrogenation with switchable selectivity upon different nickel concentration.

[0012] FIG. 6a is an AFM image of ZIS nanoplates with tip-induced artifacts. FIG. 6b is a graph showing height profiles along indicated lines of the ZIS nanoplates.

[0013] FIG. 7 is a series of TEM image of pristine ZIS NCs (left) and ZIS NCs capped with S2' ligand (right).

[0014] FIG. 8 is a representative GC traces of gas product after 6 h with 3 wt% Ni2+. Quantification of the gas products was based on the conversion factor, which was calibrated using standard samples: nH2 (TCD, retention time 0.874 min): 0.43 mmol. nCO (FID, retention time 1.089 min): 0.5 / / mol. nCH4 (FID, retention time 1.499 min): 2.6 mol. Liquid phase product (HCHO): 0.45 mmol.

[0015] FIG. 9 is a representative1H NMR (500 MHz, DMSO-tL) of crude reaction mixture after 16 h with 0.5 mmol ethyl acetate as the internal standard.Attorney Docket No. 039621.01472

[0016] FIG. 10 shows control experiments in the presence of an electron acceptor showed a high production rate of HCHO when (NH4)2S20s was used, indicating that the reduction process, specifically the hydrogen evolution reaction (HER), is the rate-determining step in this photocatalytic process without cocatalyst. The results also suggest that one role of nickel, especially at low concentrations, is to facilitate the HER. The results cannot exclude the possibility that nickel might also help in charge separation and further enhance the activity. Instead, the presence of (NHI)2S2O8 slows down the generation of EG in the presence of preadded HCHO, further supporting its formation through a reduction process involving photoelectrons.

[0017] FIG. 11 is a series of TEM images of CdS NRs (left) (Xie et al., Nat. Commun. 2018, 9(1) A 181), Zn2CdS3NRs (middle) (Wang et al., Adv. Mater., 2023, 35(5):e2205782), and ZmlmSs-hydrothermal (right) (Zhang etal., Chem. Commun., 2020, 56(12) : 1776-1779).

[0018] FIG. 12 is a series of Powder XRD patterns of CdS NRs (left), ZmCdSs NRs (middle), and ZmlmSs-hydrothermal (right).

[0019] FIG. 13 shows the UV-vis spectrum of ZIS NCs after ligand exchange (left) and its corresponding Tauc plot with band gap determined as 3.06 eV (right).

[0020] FIG. 14 is an ultraviolet photoemission spectrum (He I) of ZIS / ITO for direct determination of the work function and valence-band maximum.

[0021] FIG. 15 is a Mott-Schottky plot for which the CBM was evaluated as -0.67 V versus SHE.

[0022] FIG. 16 is a series of Powder XRD patterns of pristine ZIS NCs with native organic ligands and ZIS NCs after ligands exchange and Ni photodeposition, showing no big changes. The signals align well with the standard hexagonal ZIS reference pattern (JCPDS No. 65-2023) (Shi etal., Nat. Commun., 2022, Z3 7>: 1287).

[0023] FIG. 17 is a series of TEM images of ZIS NCs loaded with 3% Ni (left) with an enlarged view of selected area (right). The black spots marked in the image represent nickel particles (Tao etal., Energy Mater., 2022, 5(4 / 4877-4884).

[0024] FIG. 18 is a TEM image of ZIS NCs loaded with 6% Ni.

[0025] FIG. 19 shows HAADF-STEM of ZIS NCs loaded with Ni (1 wt%) and the corresponding element mapping. Au signal is from the TEM grid and Cu signal is from the clip and washers used to mount the TEM grid.

[0026] FIG. 20 shows XPS spectra of Ni 2p, Zn 2p, In 3d, and S 2p for ZIS NCs after photodeposition with 1 wt% Ni2+.Attorney Docket No. 039621.01472

[0027] FIG. 21 is an image showing a noticeable color change upon exposure to air, indicating the oxidation of Ni to NiO.

[0028] FIG. 22 shows the liquid static cell for in situ XAS measurement, composed of a three electrode cell, wafer with 100 nm SiN window, and a portable 365 nm LED light fixed to a quartz window (15 mW / cm2).

[0029] FIG. 23 is a series of XAS spectra of Ni L2,3-edge of standard dry samples (Ni foil and NiO) and a concentrated liquid sample (left), and corresponding in situ XAS of the Ni L2,3-edge measured in TFY mode. No significant changes were observed upon light irradiation.

[0030] FIG. 24 is a series of in situ EPR spectra taken during the photocatalytic reaction in the presence of DMPO as a spin-trapping agent.

[0031] FIG. 25 is an EIS Nyquist plot of ZIS NCs and ZIS NCs loaded with Ni.

[0032] FIG. 26 is a graph showing transient photocurrent density of ZIS NCs and ZIS NCs loaded withNi.

[0033] FIG. 27 depicts the photocatalytic selective dehydrogenation of prenol into prenal with hydrogen evolution.

[0034] FIG. 28 depicts the photocatalytic dehydrogenative coupling of aryl amines.

[0035] FIG. 29 depicts photocatalytic methanol dehydrogenation with non-metallic cocatalysts.DETAILED DESCRIPTION

[0036] The disclosed compositions from semiconductor material based on ZIS nanostructure serve as highly efficient photocatalysts that achieve various photocatalytic dehydrogenation, and dehydrogenative coupling reactions with high selectivity.

[0037] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as is commonly understood by one of skill in the art to which the subject matter herein belongs. As used in the specification and the appended claims, unless specified to the contrary, the following terms have the meaning indicated in order to facilitate the understanding of the present disclosure.

[0038] As used in the description and the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise. Therefore, for example, reference to “a ligand” includes mixtures of two or more such ligands.

[0039] Unless stated otherwise, the term “about” means within 10% (e.g., within 5%, 2%, or 1%) of the particular value modified by the term “about.”Attorney Docket No. 039621.01472

[0040] The transitional term “comprising,” which is synonymous with “including,” “containing,” or “characterized by,” is inclusive or open-ended and does not exclude additional, unrecited elements or method steps. By contrast, the transitional phrase “consisting of’ excludes any element, step, or ingredient not specified in the claim. The transitional phrase “consisting essentially of’ limits the scope of a claim to the specified materials or steps “and those that do not materially affect the basic characteristic(s)” of the disclosure.

[0041] With respect to compositions of the present disclosure, and to the extent the following terms are used herein to further describe them, the following definitions apply.

[0042] As used herein, the term “alcohol” refers to an organic compound of the form R-OH, wherein R is (C1-C20) alkyl, (C2-C20) alkenyl, (C2-C20) alkynyl, polyethylene glycol (C2nH4n+20n+i, wherein n is an integer from 1-20), (C2-C20) alkyl carboxylic acid and its derivatives, (C1-C20) alkyl or (Ce-Cu) aryl carbonyl (COR), nitrile (CN), (C3-C20) cycloalkyl, 3- to 14-membered heterocycloalkyl, (Ce-Cu) aryl, or 5- to 14-membered heteroaryl group, wherein the heterocycloalkyl or heteroaryl group contains one or more heteroatoms selected from N, O, and S. Representative examples of alcohols include methanol, isopropyl alcohol, prenol, 3-methyl-2-pentanol, lactic acid, cyclohexanol, phenol, and benzylalcohol.

[0043] As used herein, the term “thiol” refers to an organosulfur compound of the form R-SH, wherein R is (C1-C20) alkyl, (C2-C20) alkenyl, (C2-C20) alkynyl, polyethylene glycol (C2nH4n+20n+i, wherein n is an integer from 1-20), (C3-C20) cycloalkyl, 3- to 14-membered heterocycloalkyl, (C6-C14) aryl, or 5- to 14-membered heteroaryl group, wherein the heterocycloalkyl or heteroaryl group contains one or more heteroatoms selected from N, O, and S. In some embodiments, the thiol is a bifunctional thiol wherein the thiol contains another functional group such as a carboxylic acid. Representative examples of bifunctional thiols include 3 -mercaptopropionic acid (3 -MPA) and cy stein.

[0044] As used herein, the term “amine” refers to an organic compound of the form N(Ri)s, wherein each Ri is independently hydrogen, (C1-C20) alkyl, (C2-C20) alkenyl, (C2-C20) alkynyl, (C2-C20) alkyl carboxylic acid and its derivatives, (C1-C20) alkyl or (C6-C14) aryl carbonyl (COR), nitrile (CN), (C3-C20) cycloalkyl, 3- to 14-membered heterocycloalkyl, (C6-C14) aryl, or 5- to 14-membered heteroaryl group. Representative examples of amines include methylamine, ethylamine, diethylamine, triethylamine, aniline, benzylamine, pyrrolidine, alpha-methyl benzyl amine, amino acids, and amino acid derivatives, such as amino acid esters.

[0045] As used herein, the term “carboxylate” refers to the conjugate base of a carboxylic acid. As an example, citrate is the conjugate base of citric acid.Attorney Docket No. 039621.01472

[0046] As used herein, the term “ligand” refers to an ion or a chemical group that bonds to a central metal atom or ion. Ligands act as Lewis bases (electron pair donors), and the central atom acts as a Lewis acid (electron pair acceptor). Ligands have at least one donor atom with an electron pair used to form covalent bonds with the central atom. The ligand can be a monodentate, bidentate, or polydentate ligand. Representative examples of monodentate ligands include sulfide ion, water, hydroxide ions, and ammonia. Representative examples of bidentate ligands include ethylenediamine, oxalate ion, and phosphate. Representative examples of polydentate ligands include diethylenetriamine, tri ethylenetetramine, and ethylenediaminetetraacetate.

[0047] Unless stated otherwise, and to the extent not further defined for any particular groups, e.g., alcohol, thiol, and amine, any of the groups described herein may be substituted or unsubstituted. To the extent not disclosed otherwise for any particular group(s), the substituent(s) can be selected from the group consisting of halo, alkylhalo (e.g., CF3, CHF2, CH2F, CCI3, CHCh, CH2CI), cyano, hydroxy, (Ci-Ce) alkyl, (Ci-Ce) alkoxy, hydroxy(Ci-Ce) alkyl, amino, amino(Ci-Ce) alkyl, amino-di(Ci-Ce) alkyl, and (C3-C7) cycloalkyl.

[0048] In one aspect, compositions of the disclosure comprise:a) zinc indium sulfide (ZIS) nanocrystals,b) a ligand, andc) a cocatalyst.

[0049] In some embodiments, the ZIS nanocrystals have a lateral dimension ranging from about 1 nm to about 10 pm. In some embodiments, the ZIS nanocrystals have a lateral dimension ranging from about 1 nm to about 1000 nm. In some embodiments, the ZIS nanocrystals have a lateral dimension ranging from about 2 nm to about 750 nm. In some embodiments, the ZIS nanocrystals have a lateral dimension ranging from about 2 nm to about 500 nm. In some embodiments, the ZIS nanocrystals have a lateral dimension ranging from about 5 nm to about 250 nm. In some embodiments, the ZIS nanocrystals have a lateral dimension ranging from about 5 nm to about 100 nm. In some embodiments, the ZIS nanocrystals have a lateral dimension ranging from about 10 nm to about 50 nm. In some embodiments, the ZIS nanocrystals have a lateral dimension ranging from about 15 nm to about 25 nm.

[0050] In some embodiments, the ZIS nanocrystals have a thickness ranging from about 0.5 nm to about 50 nm. In some embodiments, the ZIS nanocrystals have a thickness ranging from about 0.5 nm to about 40 nm. In some embodiments, the ZIS nanocrystals have a thicknessAttorney Docket No. 039621.01472ranging from about 1 nm to about 30 nm. In some embodiments, the ZIS nanocrystals have a thickness ranging from about 1 nm to about 20 nm. In some embodiments, the ZIS nanocrystals have a thickness ranging from about 1 nm to about 10 nm. In some embodiments, the ZIS nanocrystals have a thickness ranging from about 1 nm to about 5 nm. In some embodiments, the ZIS nanocrystals have a thickness of about 2 nm.

[0051] In some embodiments, the ratio of lateral dimension to thickness is 1:1000 to 1000:1. In some embodiments, the ratio of lateral dimension to thickness is 1:1000.

[0052] In some embodiments, the ligand is a hydrophobic surface-capping ligand, a water-soluble ligand, or an inorganic ligand.

[0053] In some embodiments, the hydrophobic surface-capping ligand is oleylamine (OAm), trioctyl phosphine oxide (TOPO), trioctylphosphine (TOP), oleic acid (OA), trioctylamine (TOA), tetradecylphosphonic acid (TDPA), polyvinylpyrrolidone (PVP), or a thiol.

[0054] In some embodiments, the thiol is an alkyl thiol. In some embodiments, the thiol is dodecanethiol (DDT).

[0055] In some embodiments, the water-soluble ligand is a bifunctional thiol, an amino acid, an alcohol, or a carboxylate.

[0056] In some embodiments, the bifunctional thiol is 3 -mercaptopropionic acid (3-MPA).

[0057] In some embodiments, the amino acid is glycine (gly).

[0058] In some embodiments, the alcohol is polyethylene glycol (PEG).

[0059] In some embodiments, the carboxylate is citrate.

[0060] In some embodiments, the inorganic ligand is hydroxide (OH), sulfide (S2'), tetrafluorob orate (BFF), thiosulfate (S2O32'), phosphate (PO ), fluoride (F‘), chloride (CF), bromide (Br), iodide (T), astatide (At"), thiocyanate (SCN‘), AcO-, C1OF, HCCh', CIO-, NO3', Se2', MoO?', or WO?.

[0061] In some embodiments, the cocatalyst is a metal cocatalyst. In some embodiments, the metal cocatalyst is Ni, Pt, Ir, Cu, Ag, Au, Co, Fe, Ru, Rh, or Pd. In some embodiments, the metal cocatalyst is Ni, Co, Fe, or Pt. The metal cocatalyst may be present in metallic (M°) or ionic form (M”+) or a combination thereof.

[0062] In some embodiments, the metal cocatalyst has a concentration of about 0.1 wt% to about 10 wt%. In some embodiments, the metal cocatalyst has a concentration of about 0.1 wt% to about 8 wt%. In some embodiments, the metal cocatalyst has a concentration of about 0.2 wt% to about 6 wt%.Attorney Docket No. 039621.01472

[0063] In some embodiments, the cocatalyst is a non-metallic cocatalyst. In some embodiments, the non-metallic cocatalyst is M0S2, Ni2P, NiP, C02P, CoP, FeP, MoP, MoP2, RuP, R112P, NiCoP, or FeCoP. In some embodiments, the non-metallic cocatalyst is M0S2, M2P, NiP, C02P, or CoP. In some embodiments, the non-metallic cocatalyst is M0S2, M2P, or CoP.

[0064] In some embodiments, the non-metallic cocatalyst has a concentration of about 0.1 wt% to about 10 wt%. In some embodiments, the non-metallic cocatalyst has a concentration of about 0.1 wt% to about 8 wt%. In some embodiments, the non-metallic cocatalyst has a concentration of about 0.2 wt% to about 6 wt%.

[0065] The disclosed compositions also embrace all combinations of the specific ZIS nanocrystals, ligands, and metal / non-metallic cocatalysts disclosed above.

[0066] In some embodiments, the compositions comprise:a) zinc indium sulfide (ZIS) nanocrystals,b) a ligand, wherein the ligand is OAm, TOPO, 3-MPA, hydroxide (OH), sulfide (S2), an amine (RNH2), or phosphate (PO43), andc) a metal cocatalyst, wherein the metal cocatalyst is Ni, Co, Fe, Au, or Pt.The disclosed compositions also embrace all combinations of the specific ZIS nanocrystals disclosed above.Methods of Use

[0067] In some aspects, the disclosed compositions may be used in a process for alcohol dehydrogenation or alcohol dehydrogenative coupling, comprising treating an alcohol with the disclosed compositions and exposing to light. Switchable selectivity is achieved by varying the concentration of the metal cocatalyst (FIG. 2a-FIG. 2d). The production rate of ethylene glycol (EG) is more than 10 times higher compared to its bulk counterpart synthesized through the conventional hydrothermal method.

[0068] In some embodiments, the alcohol is methanol, ethanol, isopropanol, benzyl alcohol, 1-arylethyl alcohol, lactic acid, 3-methyl-2-buten-l-ol, diarylmethanol, or prenol.

[0069] In some aspects, the disclosed compositions may be used in a process for amine dehydrogenative coupling, comprising treating an amine with the disclosed compositions and exposing to light. Through this process, the production rate of diamine reached 128.3 mmol g1h which is over 15 times higher than the highest reported example in the literature.

[0070] In some embodiments, the amine is an aromatic or aliphatic amine.Attorney Docket No. 039621.01472

[0071] In some embodiments, the aromatic amine is 1-aryl methylamine, 1-aryl ethylamine, tetrahydro- 1 -naphthylamine, or furfuryl amine.

[0072] In some embodiments, the aliphatic amine is methyl amine, isopropylamine, triethylamine, an amino acid, an amino acid derivative, or cyclohexylamine.

[0073] In some aspects, the disclosed compositions may be used in a process for thiol dehydrogenative coupling, comprising treating a thiol with the disclosed compositions and exposing to light.

[0074] In some embodiments, the thiol is ethanethiol, 2-propanethiol, 2-mercaptoethanol, mercaptoacetic acid, a thiol animo acid or its derivative, benzyl mercaptan, or 1-aryl ethanethiol.

[0075] In some embodiments, the light in the processes disclosed above is UV light. In some embodiments, the UV light has a wavelength of about 365 nm to about 370 nm. In some embodiments, the light in the processes disclosed above is from a Xe lamp.

[0076] In some embodiments, the UV light has an intensity of about 30 mW / cm2. In some embodiments, the Xe lamp light has an intensity of about 120 mW / cm2.

[0077] In some embodiments, the processes disclosed above further comprises a solvent. In some embodiments, the solvent is an aprotic solvent. In some embodiments, the aprotic solvent is DMF, DMSO, PhCFs, toluene, MeCN, or THF. In some embodiments, the solvent is a protic solvent. In some embodiments, the protic solvent is water, MeOH, EtOH, iPrOH, or TFE. In some embodiments, the solvent is a solvent mixture. In some embodiments, the solvent mixture is a mixture of an aprotic solvent and a protic solvent. In some embodiments, the solvent mixture is water / DMF or water / DMSO mixture.

[0078] In some embodiments, the process is carried out at a temperature of about 20°C to about 25°C.

[0079] In some embodiments, the process is carried out over a period of about 16 hours. In some embodiments, the process is carried out over a period of about 3 days.

[0080] These and other aspects of the present disclosure will be further appreciated upon consideration of the following Examples, which are intended to illustrate certain particular embodiments of the disclosure but are not intended to limit its scope, as defined by the claims.EXAMPLES

[0081] Example 1 : Development and performance of ZIS semiconductor photocatalystAttorney Docket No. 039621.01472

[0082] Colloidal synthesis of zinc indium sulfide (ZIS) nanocrystals (NCs) was done by mixing zinc chloride and indium chloride in a solvent mixture of trioctylphosphine oxide and oleylamine. Subsequently, sulfur injection at elevated temperatures initiated the formation of the nanocrystals (FIG. la), with their zinc-to-indium ratio determined as Zm.4ln2S4.4 by inductively coupled plasma optical emission spectroscopy (ICP-OES). Transmission electron microscopy (TEM) analysis indicated the morphology of the synthesized ZIS NCs, revealing primarily hexagonal-shaped single nanoplate with lateral dimensions ranging from 15 nm to 25 nm (FIG. lb). Atomic force microscopy (AFM) further elucidated the ultrathin nature of these plates (FIG. 1c, FIG. 6a, and FIG. 6b), measuring around 2 nm in thickness, indicative of a high surface area exposure. To enhance their dispersibility in polar solvents such as methanol, a ligand exchange process was employed for the resulting nanocrystals. This process replaced the native long-chain organic ligands with water-soluble ligands such as anionic sulfide ligands, but also resulted in aggregation of the plates (FIG. 7) (Nag et al., J. Am. Chem. Soc., 2011, 733(27): 10612-10620). The ligand shell enables to improve the dispersity of ZIS nanocrystals in different solvents. For example, to enhance their dispersity in polar solvents, the hydrophobic native surface-capping ligands of the synthesized ZIS nanocrystals were exchanged with water-soluble ligands, such as 3 -mercaptopropionic acid, or inorganic ligands like sulfide (S2) and phosphate (POT ). High-resolution TEM (HRTEM) imaging of the resulting nanoplates showcased clear lattice fringes consistent with the hexagonal ZIS structure, while fast Fourier transform (FFT) of the selected area confirmed hexagonal symmetry, reflecting the observed nanoplate morphology (FIG. Id and FIG. le). Furthermore, powder X-ray diffraction (XRD) patterns corroborated the successful synthesis of hexagonal ZIS NCs (FIG. If).

[0083] ZIS NCs were utilized as the photocatalyst for photocatalytic methanol dehydrogenation, in conjunction with a Ni2+precursor, which could act as a cocatalyst through in situ photodeposition (Chai et al., J. Am. Chem. Soc., 2016, 735(32 / 10128-10131). Switchable selectivity was observed in the reaction, resulting in the generation of either HCHO or EG depending on the amount of nickel added to the aqueous methanol solution (FIG. 2a). Specifically, at nickel loadings below 0.5 wt% (relative to the ZIS photocatalyst), EG emerged as the predominant product with a production rate reaching 27.1 mmol per gram of photocatalyst per hour (mmol g'1h'1) over a 16 h period, demonstrating a selectivity of up to 88% on a carbon basis (FIG. 8 and FIG. 9). Conversely, when nickel loading surpassed 2 wt%, the selectivity distinctly shifted towards HCHO, achieving 99% selectivity in the presence ofAttorney Docket No. 039621.014726 wt% Ni2+precursor with a production rate of 61.2 mmol g'1h'1and apparent quantum efficiency (AQE) of 17.4% over a 16 h duration. Minor byproducts, including CO, CEU, and HCOOH, were typically detected at levels below 1%. It should be noted that in both cases, the activity in the presence of nickel was significantly improved compared to the bare ZIS, which delivered a hydrogen production rate of 9.3 mmol g'1h'1(FIG. 10). Both reactions were monitored over a 22-hour duration (FIG. 2b and FIG. 2c), during which the respective products steadily accumulated. The generation of EG always exhibited a pronounced increase in the later stages of the reaction, correlating with an enhanced selectivity towards EG as the reaction progressed (vide infra).

[0084] Comparative analysis with other sulfide semiconductor materials, such as CdS (Xie et al., Nat. Commun., 2018, 9(1)'.1181; Gao et al., J. Am. Chem. Soc., 2022, 144(41)'.18986-18994), Zn2In2S5(Zhang et al., Chem. Commun., 2020, 56(12)'.1776- 1779), and Zn2CdS3(Wang et al., Adv. Mater., 2023, 35(5):e2205782) (FIG. 10 and FIG. 14), which were previously recognized for their activity towards EG generation, revealed the superior performance of the synthesized ZIS NCs when coupled with nickel as the cocatalyst under same reaction conditions (FIG. 2d). This underscores the inherent advantages conferred by the nanostructure of the synthesized ZIS material, particularly when compared to the performance of Zn2In2Ss prepared via the hydrothermal method. Moreover, the observed tunable selectivity in the photocatalytic methanol dehydrogenation was also evident in these typical sulfide systems upon the addition of different amounts of Ni2+precursor, indicating its occurrence across various photocatalytic systems.

[0085] Example 2: Characterization of nickel cocatalyst via in situ photodeposition

[0086] Due to the significant effect of nickel loading on the selectivity of the reaction, further characterizations were carried out focusing on the nickel cocatalyst (FIG. 3a-FIG. 3e). Nickel undergoes a photodeposition process during the catalytic reaction, which enables the in-situ surface modification of ZIS NCs semiconductor material with a Ni° cocatalyst. In this process, methanol serves as a hole scavenger, while the Ni2+precursor was reduced by photoelectrons and directly deposit onto the surface of the nanoplates (FIG. 3a). The conduction band minimum (CBM) of the ZIS NCs (-0.63 eV vs. SHE, FIG. 13-FIG. 15) aligns favorably with the electrochemical potential of the Ni2+ / Ni° redox couple (-0.23 V vs. SHE) (Altomare et al., J. Am. Chem. Soc., 2023, 745(45 / 26122-26132). Although distinct nickel peaks were absent in the XRD pattern, due to its size and low loading, TEM imaging revealed the presence ofAttorney Docket No. 039621.01472nickel particles on the ZIS surface at high nickel loadings (>3 wt% nickel, FIG. 17 and FIG.18). Scanning transmission electron microscopy energy dispersive X-ray spectroscopy (STEM-EDS) mapping further validated the spatial homogeneous distribution of nickel at 1 wt% nickel across the ZIS nanoplates, further confirming its deposition (FIG. 3b and FIG. 19). The modification of the photocatalysts surface with cocatalysts has been shown to significantly enhance their activity. X-ray diffraction (XRD) patterns further confirmed the successful synthesis of hexagonal ZIS nanocrystals and indicated no significant changes upon ligand exchange and photodeposition of the cocatalysts (FIG. 16).

[0087] To probe the oxidation state of nickel, post-reaction X-ray photoelectron spectroscopy (XPS) analysis was first performed (FIG. 3c and FIG. 20). The XPS spectrum exhibited a peak at a binding energy of 852.5 eV attributable to metallic Ni°, indicating the successful photodeposition of nickel through a reduction process. In addition, major peaks corresponding to Ni2+were also observed. This indicated the presence of both metallic Ni° and Ni2+in the system. To mitigate the oxidation induced by air post-reaction (FIG. 21) (Niue / al., ACS Catal., 2024, 10194-10203) as well as to further corroborate the oxidation state of nickel during the photocatalysis, in-situ soft X-ray absorption spectroscopy (XAS) was performed to collect the Ni L2,3-edge absorption features during the reaction (FIG. 22). FIG. 3e shows the Ni L2,3-edge measured in surface-sensitive total electron yield (TEY) mode in a static liquid cell that mimics real photocatalytic methanol dehydrogenation conditions with 1 wt% absorbed Ni2+before and after light irradiation (vide infra). For comparison, typical Ni L2,3-edge spectra of reference samples were plotted in FIG. 3d. Under the conditions in the liquid cell, the peaks of Ni2+showed signal broadening, with some characteristic shoulder peaks merging with nearby peaks. This made it difficult to discern changes in the main peak at the Ls-edge region. Therefore, the changes at the shoulder peak of the Ni2+L2-edge (with dotted line) were of focus (Weatherup et al., J. Phys. Chem. B, 2017, 722(2 / 737-744). Upon light irradiation for 1 min, this peak diminished significantly, although not completely, indicating the reduction of Ni2+to Ni° (FIG.3e). This behavior aligns with a typical photodeposition process, which generally occurs very rapidly upon light exposure. Extending the illumination time to 5 minutes resulted in further conversion of Ni2+to Ni°. However, the Ni L2,3-edge measured in bulk-sensitive total fluorescence yield (TFY) mode did not show significant changes of Ni2+under light irradiation (FIG. 23), indicating the presence of Ni2+in the bulk phase. These experiments demonstrated that Ni2+was reduced to Ni°, although Ni2+remained present in the system.Attorney Docket No. 039621.01472

[0088] Example 3: Quantification of nickel concentration and its influence on selectivity

[0089] Using inductively coupled plasma optical emission spectrometry (ICP-OES), the actual nickel loading on the ZIS nanoplates after illumination were determined, as well as the residual nickel in the reaction solution. Elevating the concentration of the Ni2+precursor led to a corresponding increase in the amount of nickel deposited on the plates (FIG. 4a). However, residual nickel species persisted in the reaction solution regardless of the initial Ni2+precursor concentration, exhibiting a similar increasing trend with rising Ni2+precursor levels. For instance, at a 3 wt% nickel concentration, not all the introduced nickel was effectively deposited onto the ZIS plates. Monitoring the deposition progress indicated that although prolonged irradiation increased the loaded nickel from 1.0 wt% to 2.2 wt% (FIG. 4b), the deposition rate noticeably decreased as the reaction progressed, leaving a substantial amount of nickel in the solution even after long-term illumination. This incomplete photodeposition of nickel can be attributed to multiple factors, such as the decreased concentration of available Ni2+ions, the reduced availability of free electrons due to competition from other reactions, and the competing redox reactions of nickel induced by both photogenerated electrons and holes (Wenderich et al., Chem. Rev., 2016, 776(23 / 14587-14619; Liu et al., Appl. Catal., B: Environ., 2015, 772-773:58-64). Therefore, it is likely that the system consists of both Ni° and Ni2+throughout the whole photocatalytic process, which aligned with the XPS and XAS results.

[0090] Notable differences were observed when scaling the photocatalyst loading from 2 mg down to 0.5 mg, consistently showing that selectivity of EG was superior with 0.5 mg ZIS NCs, with varying nickel loadings (FIG. 4c). Upon comparing results obtained with different amounts of photocatalyst and nickel loadings, it was found that the selectivity of EG was more closely associated with the absolute nickel concentration rather than the weight percentage of nickel relative to the photocatalyst. For example, the selectivity of the reactions was nearly identical for a 2 mg catalyst with 0.25 wt% nickel and a 0.5 mg catalyst with 1 wt% nickel at similar conversions (77% vs. 82% EG selectivity), as their absolute nickel concentrations were the same. Similarly, this trend was observed when comparing a 2 mg catalyst with 1 wt% nickel to a 0.5 mg catalyst with 3 wt% nickel (36% vs. 34% EG selectivity).

[0091] Example 4: Mechanistic studies on molecular pathways

[0092] While monitoring the photocatalytic reaction, an increasing trend in EG production was observed, particularly during the later stages of the reaction. For instance, in experimentsAttorney Docket No. 039621.01472involving 0.25 wt% nickel, EG production was minimal within the initial hour, with its selectivity gradually increasing as the reaction proceeded (FIG. 2b). In contrast, HCHO was rapidly generated as the major product in the first hour and then only slowly accumulated for the rest of the reaction, which suggested that HCHO might act as an intermediate in the pathway toward EG generation (Shen etal., Catal. Sci. Technol., 2016, 6(77 / 6485-6489).

[0093] Control experiments were conducted by introducing HCHO before the reaction (FIG.5a). The results showed that the presence of formaldehyde significantly increased EG production under similar conditions, effectively accelerating the production rate from 6.5 to 13.8 mmol g1h1using ZIS NCs in the presence of nickel and from 1.9 to 7.5 mmol g1h1using bare ZIS NCs during the first hour. These findings suggest a pathway for EG generation wherein formaldehyde acts as an intermediate, initially formed during the catalytic process and subsequently converted into EG (FIG. 5b).

[0094] In-situ electron paramagnetic resonance (EPR) spectroscopy studies were conducted using DMPO as a spin-trapping agent (FIG. 5c). These studies revealed distinct radical species in the reaction system, with notable variations depending on the nickel concentration, suggesting the involvement of different reaction sites in the photocatalytic process. Similar radical species were generated both with and without a 0.25 wt% Ni2+precursor, with the hydroxymethyl radical ( CH2OH) detected as the major species. In contrast, in the presence of a 3 wt% Ni2+precursor, stronger signal intensity was observed, along with a significantly higher concentration of hydroxyl radicals (HO ) in addition to CH2OH (Zhou et al., Nat. Commun., 2022, 73(7 / 4379). The generation of HO- is attributed to water oxidation by the photogenerated hole, suggesting that the nickel particles formed during photodeposition might act as reaction sites that readily cleave polar bonds (Gao et al., ACS Sustainable Chem. Eng., 2021, 9(75 / 6188-6202). However, the reaction of HO- with methanol generated CH2OH as the major product (Schneider etal., J. Phys. Chem. Lett., 2013, 4:3479-3483), leading to similar radical intermediates in the 3 wt% nickel case as observed with 0.25 wt% nickel loading (FIG.5d).

[0095] These experimental results indicated that HCHO remains the predominant downstream product from CH2OH in the developed system, as HCHO was the major product during the first hour with 0.25 wt% nickel and throughout the entire duration with 3 wt% nickel (FIG. 2b). It is possible for HCHO to convert back to CH2OH, likely through a proton-coupled electron reduction (Shen etal., Catal. Sci. Technol., 2016, 6(77 / 6485-6489), which can result in an increase in CH2OH concentration in the system. This process further enabled theAttorney Docket No. 039621.01472coupling of CH2OH to generate EG, and EG gradually accumulated in the reaction system as an irreversible end product (FIG. 5d). The reduction of HCHO to CH2OH is interrupted by the presence of Ni2+, which acts as electron acceptors competing with HCHO, and prevented the generation of EG at high concentrations of Ni2+. Control experiments showed that the presence of an electron acceptor reagent slowed down the generation of EG (FIG. 10). The competition for electrons induced by Ni2+explains the observed switchable selectivity due to different nickel concentrations.

[0096] Example 5: Proposed mechanism for the switchable selectivity

[0097] FIG. 5e shows a mechanism to explain the switchable selectivity in this photocatalytic methanol dehydrogenation. Upon light irradiation, electron-hole pairs are generated and migrate to the surface of ZIS photocatalyst for redox processes. Initially, Ni2+is reduced to Ni° by photoelectrons with methanol consuming the photogenerated hole (FIG. 3a). This results in the formation of nickel particles, clusters, or single atoms directly on the ZIS NCs surface, depending on the nickel precursor concentration in the solution (Si et al., ACS Catal., 2024, 8343-8352; Pan et al., J. Energy Chem., 2021, 55:408-414). The deposited Ni° then facilitates proton reduction for H2 with photoelectrons, and in turn promotes methanol oxidation for HCHO using photogenerated holes, either involving HO- or not. (FIG. 10).

[0098] In the case of low nickel loadings, although HCHO is initially generated as the main product, the accumulated HCHO can couple with released protons, competing with the low concentration of Ni2+for photoelectrons, and regenerate CH2OH. This further increases the concentration of CH2OH in the reaction, facilitating its coupling and promoting EG generation, explaining the increasing selectivity for EG as the reaction progresses. In contrast, at high nickel loadings, the remaining high concentration of Ni2+in the solution, along with the hydrogen evolution reaction, effectively shield the generated HCHO from reduction by photoelectrons for EG production, thereby accounting for the high selectivity towards HCHO.

[0099] In addition to influencing reaction selectivity based on its loadings, nickel also plays a crucial role as a cocatalyst in lowering the kinetic barriers of the reaction and improving charge separation (FIG. 25 and FIG. 26). This, combined with the advantages of our ZIS nanostructure, may account for the high activity of this system.

[0100] Example 6: MaterialsAttorney Docket No. 039621.01472

[0101] Zinc chloride (98%+, Sigma Aldrich®), indium chloride (99.99%, Alfa Aesar®), TOPO (99%, Acros Organics), oleylamine (70% or 98%, Sigma Aldrich®), sulfur (99.999%, Acros Organics), (NHfriS (50% water solution, Sigma Aldrich®), nickel chloride hexahydrate (99.95%, Alfa Aesar®) were used as received. All solvents including methanol, toluene, ethanol (HPLC grade, Fischer Scientific) were used as received without further purification or modification.

[0102] Example 7: Preparation of zinc indium sulfide nanocrystals (ZIS NCs)

[0103] Colloidal synthesis of ZIS NCs

[0104] ZnCh (138 mg, 1 mmol), InCh (147 mg, 0.66 mmol), trioctylphosphine oxide (2.3 g, TOPO) were added into a three-neck flask in a glovebox. Then the flask was moved out from the glovebox and 10 mL of oleylamine (OAm) was quickly added. The resulting mixture was heated at 120 °C under vacuum for 60 min with a stirring speed of 650 rpm, after which the reaction solution was heated further to 220 °C (internal temperature). Hot injection of sulfur (51.2 mg, 1.6 mmol, dissolved in 2 mL OAm) resulted in an immediate color change from light yellow to dark red, which then gradually changed to orange yellow upon heating at 220 °C for 1 h. The mixture was then cooled down to room temperature and 30 mL ethanol was added. The precipitate was collected by centrifugation at 12000 rpm for 5 min and redissolved in toluene (10 mL). The solution was further centrifuged at 12000 rpm for 10 min and the supernatant was collected. The composition of the resulted ZIS NCs was determined by ICP after sonicating in aqua regia overnight. Size screening was further carried out using ethanol as the antisolvent for TEM images.

[0105] The ZIS nanocrystals, prepared by colloidal synthesis, are capped by a surface ligand and formed as single plates, indicative of high surface area exposure. Transmission electron microscopy (TEM) analysis revealed the hexagonal morphology of the synthesized ZIS nanocrystals, primarily showing hexagonal-shaped nanoplates with lateral dimensions ranging from 15 nm to 25 nm. Atomic force microscopy (AFM) further elucidated the ultrathin nature of these plates, measuring around 2 nm in thickness.

[0106] The ligand shell enables for the improvement of the dispersity of ZIS nanocrystals in different solvents. For example, to enhance their dispersity in polar solvents, the hydrophobic native surface-capping ligands (OAm and TOPO) of the synthesized ZIS nanocrystals were exchanged with water-soluble ligands, such as 3 -mercaptopropionic acid (3-MPA), or inorganic ligands like hydroxide (OH), sulfide (S2) and phosphate (PO43). High-Attorney Docket No. 039621.01472resolution TEM (HRTEM) imaging of the resulting nanoplates after ligand exchange showcased clear lattice fringes consistent with the hexagonal ZIS structure, while fast Fourier transform (FFT) selected area electron diffraction patterns confirmed hexagonal symmetry, correlating with the observed pristine nanoplate morphology (FIG. 1g).

[0107] Ligand exchange

[0108] The hydrophobic native surface-capping ligands of the as-synthesized ZIS NCs were subsequently replaced with inorganic sulfide (S2‘) ligand following a previously reported procedure. An aliquot (10 mg, -700 gL in toluene) of the native ligand capped ZIS NRs was added to a solution of (NH4)2S (5 z / L, 50% water solution) in 5 mL Mm ethyl foramide (NMF), the resulting suspension was stirred at room temperature for 20 min. 35 mL of toluene was then added and the resulting mixture was centrifuged at 12000 rpm for 5 min. The solid was collected and wash three times with 3 mL MeOH and then redispersed in 5 mL water.

[0109] Photocatalytic methanol dehydrogenation

[0110] The dispersion of ZIS NCs (2 mg / mL in water) was sonicated for 30-60 seconds to ensure an uniform dispersion. Then ZIS NCs (2 mg, dispersed in 1 mL water), NiCh 6H2O (5-120 gg Ni, 0.25-6 wt%, 10-240 g stock solution in water), and methanol (4 mL) were added into a 30 mL quartz tube (with a diameter of 1.5 cm). The tube was sealed with an adaptor equipped with a three-way valve and purged with argon. The reaction mixture was then exposed to 365 nm light with a light intensity close to 30 mW / cm2for a specified duration, while a fan maintained the reaction at room temperature. The gas generated was analyzed using GC chromatography, while the organic product was measured by NMR.Notes:1. HCHO converts into methoxymethanol in 80% MeOH solution spontaneously, which can be directly detected by NMR in DMSO-zL (peaks at 4.5 ppm and 6.2 ppm). In addition, HCHO can be quantified by HPLC or formaldehyde Nash colorimetric assay (Soland et al., ACS Sustain. Chem. Eng., 2023, 77(3 / 12478-12483) to determine its concentration. 2. The major gas products CO and CH4 typically constitute less than 1% on a carbon basis.Similarly, side organic products like formic acid and glyceraldehyde exhibit a similar situation.3. The selectivity of EG and HCHO was calculated on carbon basis (Zhang et al., Chem.Commun, 2020, 56(72 / 1776-1779):SelectivityEG = 2nEG / (2nEG + nucuo + nside products)x100% SelectivityncHo = nncHo / (2nEG + nucuo + nside products)x100%Attorney Docket No. 039621.01472

[0111] Example 8: Characterization methods

[0112] Transmission electron microscopy (TEM)

[0113] Low-magnification images were taken on the Hitachi H-7650 microscope. High resolution TEM images were acquired with the TEAM0.5 microscope located at the National Center for Electron Microscopy (Lawrence Berkeley National Laboratory). HRTEM imaging was conducted at 80 kV accelerating voltage. The electron beam was monochromated and corrected for aberrations. The HRTEM data was fitted with a contrast transfer function (Oddo et al., Nano Lett., 2023, 23(24 / 11469-11476). ZIS NCs dispersion (25 z / g / mL, hexane) were drop-cast onto ultrathin carbon-coated Cu or Au TEM grids for imaging.

[0114] Atomic force microscopy (AFM)

[0115] AFM was performed using a Bruker Veeco atomic force microscope at the Advanced Light Source facility of the Lawrence Berkeley National Laboratory. The sample was prepared by drop-casting a drop of ZIS nanocrystals (25 wg / mL, hexane) onto a silicon wafer, followed by O2 plasma cleaning for 30 seconds.

[0116] Powder X-ray Diffraction (PXRD)

[0117] PXRD data were collected using a Rigaku Miniflex 6G Benchtop Powder XRD with a Cu Ka radiation source in ambient conditions. The powders were flattened onto a glass slide for measurements.

[0118] Nuclear magnetic resonance (NMR)

[0119] All 'H NMR and13C NMR spectra were recorded on a Bruker AVANCE III HD 500MHz NMR spectrometer and reported in ppm (6). Chemical shifts were referenced to the residual solvent peaks.

[0120] NMR sample preparation: 0.5 mmol of ethyl acetate (49.1 z / L) was added into the reaction mixture, and 8 drops of the resulting solution was transferred into the NMR tube followed by adding 0.6 mL DMSO-A (NMR measuring parameters: dl = 4 s, NS = 32; auto linear correction was applied for the integration).

[0121] Gas chromatograph (GC)

[0122] Gas products were quantified by a gas chromatograph (Agilent Technologies, 7890B, carrier gas: He) equipped with a thermal conductivity detector and a flame ionization detector.

[0123] UV-vis Absorption Spectroscopy (UV-vis)

[0124] The optical absorption spectrum was acquired using a UV-vis spectrometer (UV-2600, Shimadzu). The sample can be either a liquid sample (0.6 mg / mL in water) or a thin film.Attorney Docket No. 039621.01472For thin film preparation, initially, 10 / L of ZIS NCs dispersion (0.6 mg / mL in water) was deposited onto a quartz slide, and upon heating to 70 °C, water was evaporated to form a thin film of ZIS NCs. A background scan was conducted solely for the quartz slides in this case. Subsequently, the Tauc plot was derived from the absorption spectrum, plotting (ahv)2against hv.

[0125] Ultraviolet photoelectron spectroscopy (UPS)

[0126] XPS and UPS were measured with a PHI Versa Probe IV multi -technique instrument at Stanford Nano Shared Facilities (SNSF, RRID:SCR_023230). For XPS, the measurement was carried out using an Al Ka source (Photon energy 1486.6 eV) and 224 eV pass energy, with electron and ion neutralization. UPS was performed using He I as the photon source operating at 1000 V and 100 mA. The sample was prepared by dropping a 10 L aliquot of ZIS NCs dispersion (0.6 mg / mL in water) onto an indium tin oxide (ITO) substrate, and upon heating to 70 °C, water was evaporated to form a thin film of ZIS NCs. The data was collected with 10 V bias. The work function and valence band maximum (VBM) of ZIS nanocrystals were measured by UPS to be -3.93 eV and -6.87 eV versus vacuum, respectively. The work function was calculated by subtracting the He I radiation energy of 21.2 eV from the high-binding energy cutoff at 17.27 eV (Fig. S2a): (7.27 + 10) eV - 21.2 eV = -3.93 eV versus vacuum, and therefore the VBM was calculated to be -3.93-(-7.06+10) = -6.87 eV versus vacuum, which is 2.43 vs SHE (Fabian et al., J. Mater. Chem. A, 2016, 4(75 / 6837-6841).

[0127] Photoelectrochemical Measurements

[0128] The photoelectrochemical measurements utilized a conventional three-electrode configuration (Huang et al., ACS Catal., 2024, 74(7 4581-4592). Initially, an aliquot of ZIS NCs dispersion (0.6 mg / mL in water) was deposited onto an indium tin oxide (ITO) substrate, forming a thin film of ZIS NCs (0.6 cm x 0.8 cm) upon heating to 70 °C to facilitate water removal. This ZIS NCs layer functioned as the working electrode. An Ag / AgCl electrode with a potential of 0.21 V versus the Standard Hydrogen Electrode (SHE) was utilized as the reference electrode, while a platinum wire served as the counter electrode. The electrolyte solution employed was 0.5 M Na2SC>4 for Mott-Schottky analysis, and 0.5 M Na2SC>4 and 0.1 M methanol for electrochemical impedance spectra and photocurrent measurement. Flat band measurement (Mott- Schottky) was conducted under dark conditions with the potential and frequency ranging from -1.0 to 1.2 V (vs. Ag / AgCl, pH = 7) and from 500 to 1500 Hz, respectively. The electrochemical impedance spectra (EIS) were carried out under the frequency ranges from 1 to 1000 kHz, with a bias of -0.75 V. The photocurrent measurementAttorney Docket No. 039621.01472was carried out with an interval of 20 s under Xe lamp AM 1.5 G irradiation with a bias of -0.1 V.

[0129] Energy dispersive X-ray spectroscopy (EDS)

[0130] High-angle annular dark-field scanning transmission electron microscope (HAADF-STEM) and energy dispersive X-ray spectroscopy (EDS) mapping analysis were performed with Thermo Fisher Scientific® TitanX 60-300 at Lawrence Berkeley National Laboratory (LBL) with an accelerating voltage of 80 kV. STEM-EDS 140 eV energy resolution; windowless Si drift detectors, total solid angle 0.7 steradian.

[0131] Sample preparation: ZIS NCs dispersion (0.4 mg / mL, 80% methanol) in the presence of 1 wt% Ni2+precursor was exposed to Xe lamp under Ar for 3 h, and then drop-cast onto ultrathin carbon-coated Au TEM grids for imaging.

[0132] X-ray photoelectron spectroscopy (XPS)

[0133] XPS spectra were recorded using Thermo Fisher Scientific® K-Alpha Plus™ X-ray Photoelectron Spectroscope with a monochromatic Al-Ka source at Molecular Foundry at Lawrence Berkeley National Laboratory (LBL).

[0134] Sample preparation: ZIS NCs dispersion (0.4 mg / mL, 80% methanol) in the presence of 1 wt% Ni2+precursor was exposed to Xe lamp under Ar for 3 h, and then the solid was collected by centrifugation and redispersed in 0.5 mL methanol. The dispersion was drop-casted onto carbon paper under a N2 flow, and then dried and stored under N2 until measurement.

[0135] In situ X-ray absorption spectroscopy (XAS)

[0136] In situ soft XAS was performed on Beamline 8.0.1.4 in the Advanced Light Source, Lawrence Berkeley National Laboratory (Velasco-Velez etal., Science, 2014, 346(6217 / 831-834). The experiment was conducted in a static liquid cell with an ultrathin SiiN4 membrane window (100 nm thick) that separates the liquid medium inside the cell from the ultrahigh-vacuum environment (FIG. 6a and FIG. 6b). The first scan after every light irradiation were collected for the comparison purpose.

[0137] XAS samples preparation

[0138] Standard dry sample: Ni foil (freshly polished), NiO (dispersed in ethanol and dropcase onto a carbon paper).

[0139] Standard liquid sample: ZIS NCs dispersed in 80% aqueous methanol (10 mg, 2 mg / mL) was mixed with 2 wt% Ni2+(NiCh 6H2O). After settle down of the ZIS NCs, the bottom ZIS NCs concentrated layer was transferrd into the cell.Attorney Docket No. 039621.01472

[0140] In situ XAS sample: ZIS NCs dispersed in 80% aqueous methanol (10 mg, 0.4 mg / mL,) was mixed with 6 wt% Ni2+(NiCh 6H2O) and stand overnight to absorb Ni2+. The resutling ZIS NCs with Ni2+(determined as ~1.0 wt% Ni by ICP) was collected by centrifugation and further dispersed into 80% methanol (2 mg / mL). After setting of the ZIS NCs, the bottom ZIS NCs concentrated layer was transferred into the cell. This method aims to observe evident changes upon light irradiation, preventing free Ni2+in the solution from interfering with the test.

[0141] Inductively coupled plasma optical emission spectroscopy (ICP-OES)

[0142] ICP-OES measurement was performed using PerkinElmer Optima 7000 DV. The mole ratio of Zn to In was determined to be 1.4 ± 0.05 : 2 for different batches, close to the EDS measurement.

[0143] Electron Paramagnetic Resonance (EPR)

[0144] Continuous-wave (CW) X-band electron paramagnetic resonance (EPR) measurements were performed at room temperature using a Bruker Elexys E580 spectrometer equipped with a ER4119HS High-Q CW resonator operating at a frequency of 9.86 GHz. All spectra were recorded with a modulation frequency of 100 Hz and modulation amplitude of 1 G. The microwave power used for all spectra was 0.5972 mW and was spot-checked by attenuating the power to determine that the signal response was linear. While these parameters may lead to minor broadening of the narrow lines for the organic radicals in the present study, they were necessary to improve the sensitivity to allow for the detection of the low-concentration photoradical products (Jin etal., ACS Photonics, 2023, 70(3 772-779).

[0145] To prepare the samples, specific amounts of NiC12-6H2O stock solution (0 wt%, 0.25 wt%, and 3 wt% Ni) were added to the ZIS NCs dispersion. The ZIS NCs dispersion consisted of 2 mg ZIS in 4 mL MeOH and 1 mL H2O. Additionally, 100 u of fresh 5,5-dimethyl-l-pyrroline-N-oxide (DMPO) solution (0.1 mg / mL) was added to the mixture. After thorough mixing, 40 u of the resulting mixture was transferred into an EPR quartz tube with a 2 mm diameter. Subsequently, the EPR tube was placed in the microwave cavity of the EPR spectrometer. Spectra were recorded under two conditions: either in the dark, or under a 365 nm LED with data collected after 4 minutes of irradiation at room temperature.

[0146] Example 9: Photocatalytic prenol dehydrogenation

[0147] The dispersion of ZIS nanocrystals, capped with PC>43' ligand, (2 mg / mL in water) was sonicated for 30-60 seconds to ensure uniform dispersion. Then ZIS nanocrystals (1 mg,Attorney Docket No. 039621.01472dispersed in 0.5 mL water), IfcPtCle (10 z / g Pt, 1 wt%, 20 / L stock solution in water), prenol (0.1 mmol, 10.1 z / L), DMSO (1 mL) and water (2.5 mL) were added into a 30 mL quartz tube (with a diameter of 1.5 cm). The tube was sealed with an adaptor equipped with a three-way valve and purged with argon. The reaction mixture was then exposed to a Xe lamp with a light intensity close to 120 mW / cm2for 15-16 h, while a fan maintained the reaction at room temperature. The gas generated was analyzed using GC chromatography, while the organic product was quantified byJH NMR (FIG. 27).

[0148] Prenol was dehydrogenated photocatalytically using ZIS nanocrystals as the photocatalyst and platinum (Pt) as the cocatalyst. This setup achieved an 80-90% conversion of 0.1 mmol prenol, generating prenal with over 90% selectivity within 16 hours of illumination under a Xe lamp. The use of a highly dilute solution and the addition of organic solvents with weak oxygen-donor, such as DMSO or dioxane, helped to prevent side reactions of prenol.

[0149] Example 10: Photocatalytic aryl dehydrogenative coupling of amines

[0150] The dispersion of ZIS nanocrystals, capped with S2' ligand (2 mg / mL in DMF) was sonicated for 30-60 seconds to ensure uniform dispersion. Then ZIS nanocrystals (2 mg, dispersed in 1 mL DMF), NiCh 6H2O (60 z / g Ni, 3 wt%, 120 z / L stock solution in DMF), aryl amines (1 mL) and DMF (2 mL) were added into a 30 mL quartz tube (with a diameter of 1.5 cm). The tube was sealed with an adaptor equipped with a three-way valve and purged with argon. The reaction mixture was then exposed to 365 nm light with a light intensity close to 30 mW / cm2for 15-16 h, while a fan maintained the reaction at room temperature. The gas generated was analyzed using GC chromatography, while the organic product was measured by GC and quantified byJH NMR (FIG. 28).

[0151] Dehydrogenative amine coupling was achieved using aryl amines as the substrate, with ZIS nanocrystals capped with sulfide ligand as the photocatalyst. The cocatalyst loading was crucial for the reaction's activity, with a 3 wt% Ni loading exhibiting almost twice the activity compared to a 0.25 wt% Ni loading. Although the reaction showed higher activity in water, it also induced some side reactions, such as imine and alcohol generation. DMF was found to be an effective solvent for this coupling reaction regarding both the activity and selectivity after several screenings. For benzylamine coupling, a 45% conversion of 9.1 mmol starting material can be achieved with over 90% selectivity. However, due to the presence of alpha protons, some side reactions of the generated diamine product occur at high conversions of benzyl amine, reducing its selectivity (e.g., 75% selectivity at 90% conversion). For alphaAttorney Docket No. 039621.01472methylbenzylamine dehydrogenative coupling, excellent performance was achieved with almost complete conversion of 7.7 mmol substrate into the target diamine product with over 95% selectivity.

[0152] Example 11 : Photocatalytic methanol dehydrogenation with non-metallic cocatalysts

[0153] The dispersion of ZIS nanocrystals, capped with S2' ligand (2 mg / mL in water) was sonicated for 30-60 seconds to ensure uniform dispersion. Then ZIS nanocrystals (2 mg, dispersed in 1 mL water), CoP (0.02-0.2 mg, 1-10 wt%), methanol (4 mL) were added into a 30 mL quartz tube (with a diameter of 1.5 cm). The tube was sealed with an adaptor equipped with a three-way valve and purged with argon. The reaction mixture was then exposed to 370 nm light with a light intensity close to 30 mW / cm2for 15-16 h, while a fan maintained the reaction at room temperature. The gas generated was analyzed using GC chromatography, while the organic product was quantified by 'HNMR. (FIG. 29).

[0154] Methanol dehydrogenation was achieved using methanol as the substrate, with ZIS nanocrystals capped with sulfide ligand and decorated with 0.02-0.2 mg of cocatalyst as the photocatalyst. This setup achieved a rate of 20 mmol g'1h'1of hydrogen production, generating ethylene glycol with selectivity of 80%, shown in FIG. 29.

[0155] All patent publications and non-patent publications are indicative of the level of skill of those skilled in the art to which this disclosure pertains. All these publications are herein incorporated by reference to the same extent as if each individual publication were specifically and individually indicated as being incorporated by reference.

[0156] Although the disclosure herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present disclosure. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present disclosure as defined by the appended claims.

Claims

Attorney Docket No. 039621.01472What is claimed is:

1. A composition comprising:a) zinc indium sulfide (ZIS) nanocrystals,b) a ligand, andc) a cocatalyst.

2. The composition of claim 1, wherein the ZIS nanocrystals have a lateral dimension ranging from about 1 nm to about 10 pm.

3. The composition of claim 2, wherein the ZIS nanocrystals have a lateral dimension ranging from about 15 nm to about 25 nm.

4. The composition of any one of claims 1-3, wherein the ZIS nanocrystals have a thickness ranging from about 0.5 nm to about 50 nm.

5. The composition of claim 4, wherein the ZIS nanocrystals have a thickness of about 2 nm.

6. The compound of any one of claims 1-5, wherein the ratio of lateral dimension to thickness is 1:1000 to 1000:1.

7. The composition of any one of claims 1-6, wherein the ligand is a hydrophobic surfacecapping ligand, a water-soluble ligand, or an inorganic ligand.

8. The composition of claim 7, wherein the hydrophobic surface-capping ligand is oleylamine (OAm), trioctylphosphine oxide (TOPO), trioctylphosphine (TOP), oleic acid (OA), trioctylamine (TOA), tetradecylphosphonic acid (TDPA), polyvinylpyrrolidone (PVP), or a thiol.

9. The composition of claim 7, wherein the water-soluble ligand is a bifunctional thiol, an amino acid, an alcohol, or a carboxylate.Attorney Docket No. 039621.0147210. The composition of claim 7, wherein the inorganic ligand is hydroxide (OH), sulfide (S2'), tetrafluorob orate (BFT), thiosulfate (S2O32'), phosphate (PO ), fluoride (F‘), chloride (CF), bromide (Br), iodide (F), astatide (At"), thiocyanate (SCN‘), AcO-, ClOF, HCCh', CIO-, NO3', Se2', MoO , or WO?.

11. The composition of any one of claims 1-10, wherein the cocatalyst is a metal cocatalyst.

12. The composition of claim 11, wherein the metal cocatalyst is Ni, Pt, Ir, Cu, Ag, Au, Co, Fe, Ru, Rh, or Pd.

13. The composition of claim 12, wherein the metal cocatalyst is Ni, Co, Fe, Au, or Pt.

14. The composition of any one of claim 1-10, wherein the cocatalyst is a non-metallic cocatalyst.

15. The composition of claim 14, wherein the non-metallic cocatalyst is M0S2, M2P, NiP, C02P, CoP, FeP, MoP, MoP2, RuP, Ru2P, NiCoP, or FeCoP.

16. The composition of claim 15, wherein the non-metallic cocatalyst is M0S2, M2P, NiP, C02P, or CoP.

17. The composition of any one of claims 11-16, wherein the metal or non-metallic cocatalyst has a concentration of about 0.1 wt% to about 10 wt%.

18. The composition of claim 17, wherein the metal or non-metallic cocatalyst has a concentration of about 0.2 wt% to about 6 wt%.

19. A process for alcohol dehydrogenation or alcohol dehydrogenative coupling, comprising treating an alcohol with the composition of any one of claims 1-18 and exposing to light.

20. The process of claim 19, wherein the alcohol is methanol, ethanol, isopropanol, benzyl alcohol, 1 -arylethyl alcohol, lactic acid, 3-methyl-2-buten-l-ol, diarylmethanol, or prenol.Attorney Docket No. 039621.0147221. A process for amine dehydrogenative coupling, comprising treating an amine with the composition of any one of claims 1-18 and exposing to light.

22. The process of claim 21, wherein the amine is an aromatic or aliphatic amine.

23. The process of claim 22, wherein:a) the aromatic amine is 1-aryl methylamine, 1-aryl ethylamine, tetrahydro- 1 -naphthylamine, or furfuryl amine, orb) the aliphatic amine is methyl amine, isopropylamine, triethylamine, an amino acid, an amino acid derivative, or cyclohexylamine.

24. A process for thiol dehydrogenative coupling, comprising treating a thiol with the composition of any one of claims 1-18 and exposing to light.

25. The process of claim 24, wherein the thiol is ethanethiol, 2-propanethiol, 2-mercaptoethanol, mercaptoacetic acid, a thiol animo acid or its derivative, benzyl mercaptan, or 1-aryl ethanethiol.

Images