Application of Z-type CdS-coated g-C3N4 in activation of benzyl and aliphatic sp3C-H and photocatalytic carboxylation of CO2

Abstract

The invention discloses an application of Z type CdS (at) g-C3N4 in activation of benzyl and aliphatic sp3 C-H and photocatalytic carboxylation of CO2 (carbon dioxide). The preparation method of the CdS (at) g-C3N4 catalyst comprises the step of preparing the CdS (at) g-C3N4 heterojunction by a simple and convenient calcination method. The Z-type CdS (at) g-C3N4 heterojunction is used for activation of benzyl and aliphatic sp3 C-H and photocatalytic carboxylation of CO2. The Z-type pathway in CdS (at) g-C3N4 significantly improves the separation efficiency of charge carriers, and enhances the accumulation of photo-induced electrons on a g-C3N4 shell. This in turn promotes the adsorption and activation process of CO2. The research not only provides a novel heterogeneous photocatalysis strategy, but also successfully converts cheap and easily available chemicals into high-value carboxylic acid with increased carbon chains under mild conditions.

Description

Technical Field

[0001] The present invention relates to Z-type CdS@g-C 3 N 4 and its application in benzyl and aliphatic sp 3 C-H activation and CO 2 photocatalytic carboxylation. Background Art

[0002] The rising global carbon dioxide level caused by the excessive consumption of fossil fuels has become the main cause of the global greenhouse effect. Everything has two sides, and CO 2 can also be regarded as an available, abundant and renewable C1 resource. Therefore, the conversion of CO 2 into valuable chemicals has attracted great interest. In addition to the widely studied reduction of CO 2 to various chemical products such as formic acid, carbon monoxide, formamide, methanol and methylamine, the catalytic carboxylation using CO 2 as a carbon source to produce value-added fine chemicals may be a more promising option for sustainable development. After nearly a decade of continuous efforts, it is now possible to achieve the production of fine chemicals through CO 2 carboxylation by photocatalytic activation of C-halogen bonds, unsaturated olefin sp 2 C-H bonds, aromatic ring sp 3 C-H bonds and inert sp 2 C-H bonds. So far, photocatalytic C-H activation and CO 2 carboxylation are mainly limited to homogeneous catalytic systems. Achieving C-H activation and CO 2 utilization in heterogeneous photocatalytic systems to produce valuable carboxylic acids remains a highly challenging and attractive goal.

[0003] Heterogeneous photocatalysis has many advantages, including easy separation, low cost and low pollution. It is an effective and promising way to achieve new organic transformations. So far, some heterogeneous photocatalytic reactions have been studied to achieve the efficient synthesis of valuable chemicals. Considering the dependence on a large amount of expensive and dangerous oxidants in traditional oxidative C-H activation, this affects the sustainability of C-H activation. Photocatalysis provides a promising method to achieve C-H activation under mild conditions.

[0004] An ideal photocatalyst should have an appropriate band gap, good reducibility and good photostability. Among them, the typical semiconductor photocatalytic material g-C 3 N 4It has been widely studied in heterogeneous systems due to its appropriate energy band structure, high chemical / thermal stability, and ease of preparation. Meanwhile, metal sulfide photocatalysts are widely used in photocatalysis, usually showing good compatibility with the reaction environment, high stability, and strong reduction ability. Z-scheme heterojunctions can effectively separate charge carriers while maintaining the optimal conduction band (CB) and valence band (VB), thus maintaining a high redox potential. Summary of the Invention

[0005] The present invention discloses Z-scheme CdS@g-C 3 N 4 in the application of benzyl and aliphatic sp 3 C-H activation and CO 2 photocatalytic carboxylation, which is characterized in that: through photocatalysis without a sacrificial agent, benzyl and aliphatic sp 3 C-H activation and CO 2 carboxylation can produce aryl acids and alkyl carboxylic acids with increased carbon chains; Preparation of CdS photocatalyst: Add 10 mmol Cd(NO 3 ) 2 ·4H 2 O, 30 mmol NH 2 CSNH 2 , 50 mL of ethylenediamine into a Teflon-lined stainless steel autoclave, react the mixture at 160 °C for 48 hours, separate the yellow solid after cooling, wash it 5 times with H 2 O / EtOH, and dry it under vacuum to prepare CdS nanorods; Preparation of Z-scheme CdS@g-C 3 N 4 : Add 200 mg of CdS nanorods to 30 mL of ethanol, stir for 1 hour, add 45 mg of melamine and stir for another 1 hour, centrifuge to obtain an intermediate, and dry it under vacuum at 60 °C. The intermediate is calcined at 500 °C for 2 h under nitrogen to obtain Z-scheme CdS@g-C 3 N 4 ; Preparation of acids with increased carbon chains by benzyl and aliphatic sp 3 C-H activation and CO 2 carboxylation: In an atmosphere of 1 atm CO 2 , add 10 mg of the catalytic material, 0.2 mmol of the substrate, 0.4 mmol of K 3 PO 4Put 2 mL of the solvent into a two-necked flask and irradiate the reaction with a 10 W blue LED at room temperature for 24 hours; the substrates include toluene, benzyl chloride, benzyl bromide, o-xylene, p-xylene, m-xylene, mesitylene, p-methylanisole, 4-nitrotoluene, 2-methylbenzotrifluoride, 3-methylbenzotrifluoride, 4-methylbenzotrifluoride, cyclohexane, cyclopentane, and tetrahydrofuran.

[0006] Z-type CdS@g-C 3 N 4 In the benzyl and aliphatic sp 3 C-H activation and CO 2 Application in photocatalytic carboxylation, characterized in that: the yield of carboxylic acids with increased carbon chains can reach 72% - 95%.

[0007] Z-type CdS@g-C 3 N 4 In the benzyl and aliphatic sp 3 C-H activation and CO 2 Application in photocatalytic carboxylation, characterized in that: in a 1 atm CO 2 atmosphere, put 10 mg of Z-type CdS@g-C 3 N 4 , 0.2 mmol of toluene, 0.4 mmol of K 3 PO 4 and 2 ml of the solvent MeCN into a two-necked flask and irradiate the reaction with a 30 W blue LED at room temperature for 24 hours. The conversion rate of toluene is 99%, and the selectivity for p-methylbenzoic acid is 100%.

[0008] Z-type CdS@g-C 3 N 4 In the benzyl and aliphatic sp 3 C-H activation and CO 2 Application in photocatalytic carboxylation, characterized in that: in a 1 atm CO 2 atmosphere, put 10 mg of Z-type CdS@g-C 3 N 4 , 0.2 mmol of toluene, 0.4 mmol of K 3 PO 4 and 2 ml of the solvent DMF into a two-necked flask and irradiate the reaction with natural light at room temperature for 8 hours. The conversion rate of toluene is 56%, and the selectivity for phenylacetic acid is 95%.

[0009] Z-type CdS@g-C 3 N 4 In the benzyl and aliphatic sp 3 C-H activation and CO 2Applications in photocatalytic carboxylation, characterized in that: the Z-type CdS@g-C used for the catalytic conversion of toluene 3 N 4 Recycled after use, washed, centrifuged, and dried for the next cycle. During the second, third, and fourth cycle experiments, the toluene conversion rate and selectivity can both be maintained at a level above 95%. By the fifth cycle, the conversion rate is maintained above 90% and the selectivity is maintained above 95%. Description of the Drawings

[0010] Figure 1 is the catalyst CdS, g-C prepared in Example 1 3 N 4 and CdS@g-C 3 N 4 X-ray diffraction (XRD) patterns, scanning electron microscopy (SEM) images, and high-resolution transmission electron microscopy (HRTEM) images. (a) CdS nanorods, g-C 3 N 4 and CdS@g-C 3 N 4 XRD patterns; (b) SEM image of CdS@g-C 3 N 4 ; (c) Transmission electron microscopy (TEM) image of CdS@g-C 3 N 4 ; (d) HRTEM image of CdS@g-C 3 N 4 .

[0011] Figure 2 is the X-ray photoelectron spectroscopy (XPS) of the catalysts CdS, g-C 3 N 4 and CdS@g-C 3 N 4 . (a) C 1s; (b) N 1s; (c) Cd 3d; (d) S 2p.

[0012] Figure 3 is the catalysts CdS, g-C prepared in Example 1 3 N 4 and CdS@g-C 3 N 4 Ultraviolet-visible diffuse reflectance spectra, band gaps, and Mott-Schottky curves. (a) CdS, g-C 3 N 4 and CdS@g-C 3 N 4 ultraviolet-visible diffuse reflectance spectra; (b) CdS, g-C3 N 4 and CdS@g-C 3 N 4 band gap; (c) Mott-Schottky curve of CdS; (d) Mott-Schottky curve of g-C 3 N 4 .

[0013] Figure 4 is Example 1 for preparing the catalysts CdS, g-C 3 N 4 and CdS@g-C 3 N 4 photocurrent experiments, electrochemical impedance (EIS) spectra, and photoluminescence (PL) spectra of the prepared samples. (a) Photocurrent experiments; (b) EIS spectra; (c) PL spectra of the prepared samples. Detailed Description of the Invention

[0014] The present invention will be described in detail below with reference to specific examples.

[0015] Example 1 Preparation of CdS photocatalyst: Add 10 mmol of Cd(NO 3 ) 2 ·4H 2 O, 30 mmol of NH 2 CSNH 2 , and 50 mL of ethylenediamine into a Teflon-lined stainless steel autoclave. React the mixture at 160 °C for 48 hours. After cooling, separate the yellow solid, wash it 5 times with H 2 O / EtOH, and dry it under vacuum to obtain CdS nanorods.

[0016] g-C 3 N 4 photocatalyst preparation: Calcinate 10 g of melamine at 500 °C under nitrogen for 2 h (heating rate: 5 °C / min) to obtain g-C 3 N 4 ; Z-scheme CdS@g-C 3 N 4 photocatalyst preparation: Add CdS nanorods (200 mg, 0.9 mmol) to 30 mL of ethanol, stir for 1 hour, add melamine (45 mg, 0.2 mmol), and stir for another 1 hour. Centrifuge to obtain the intermediate, and dry it under vacuum at 60 °C. Then, calcine the intermediate at 500 °C under nitrogen for 2 h (heating rate: 5 °C / min) to obtain Z-scheme CdS@g-C3 N 4 。

[0017] X-ray diffraction patterns were used to detect the crystal phases of CdS, g-C 3 N 4 and CdS@g-C 3 N 4 The diffraction peaks of CdS nanorods are shown in Fig. 1a. All the diffraction peaks of CdS correspond to the wurtzite structure. The characteristic peaks are at 24.8°, 26.5°, 28.2°, 36.6° and 43.7°, which are the (100), (002), (101), (102) and (110) crystal planes of CdS (JCPDS No. 41-1049), respectively. g-C 3 N 4 shows a diffraction peak at approximately 27.1°, which is attributed to the (002) crystal plane. After in-situ formation of the Z-scheme CdS@g-C 3 N 4 by calcination, the characteristic peaks of the heterojunction material are close to those of the original CdS, indicating that the crystal phase of CdS is well maintained. No peaks of g-C 3 N 4 are detected in Z-scheme CdS@g-C 3 N 4 , which is attributed to the low content and low crystallinity of g-C 3 N 4 in Z-scheme CdS@g-C 3 N 4 .

[0018] Scanning electron microscopy (SEM) images and transmission electron microscopy (TEM) images were used to characterize the microstructure and lattice structure of Z-scheme CdS@g-C 3 N 4 Fig. 1b shows the SEM image of Z-scheme CdS@g-C 3 N 4 after calcination. Z-scheme CdS@g-C 3 N 4 shows a nanorod morphology with dimensions of approximately 300 nm in length and 50 nm in diameter. After the formation of the Z-scheme CdS@g-C 3 N 4 heterojunction, the surface of the nanorods becomes significantly rougher, and g-C 3 N 4 covering the surface of CdS can be clearly observed. In addition, the formation of the heterojunction was also confirmed by the TEM image in Figure 1 Fig. 1c. TEM image analysis also shows that the rod-shaped cadmium sulfide is tightly wrapped by g-C 3 N 4 .Figure 1 The high-resolution transmission electron microscopy (HRTEM) image in d shows that the lattice spacing of 0.32 nm corresponds to the (101) crystal plane of CdS.

[0019] XPS is used to analyze the chemical elements and their chemical states on the surface of CdS, g-C 3 N 4 and Z-scheme CdS@g-C 3 N 4 The high-resolution XPS of C 1s in a shows that the peaks at 284.6, 286.2, and 288.2 eV correspond to C-C, C-N, and N-C=N bonds, respectively. As Figure 2 shown in Figure 2 b, the N 1s spectrum shows two peaks at binding energies of 398.8 and 400.5 eV, which are attributed to C-N=C and N-(C) 3 . The peak position of N-(C) 3 in the N 1s XPS spectrum shifts to a higher binding energy, which can be interpreted as the formation of a Z-scheme CdS@g-C 3 N 4 heterojunction during the calcination process. In Figure 2 c, the XPS spectrum of Cd 3d is fitted into peaks at 410.9 eV and 404.2 eV, which are attributed to Cd 3d 3 / 2 and Cd 3d 5 / 2 , respectively. Figure 2 d shows the XPS spectra of S 2p in CdS and Z-scheme CdS@g-C 3 N 4 . The peaks at 160.6 eV and 161.8 eV are S 2p 3 / 2 and S 2p 1 / 2 , respectively. The Cd 3d and S 2p signals of Z-scheme CdS@g-C 3 N 4 both shift to lower binding energies, which should be attributed to the change in the chemical environment of the CdS crystal structure caused by the formation of the heterojunction.

[0020] The optical properties of CdS, g-C 3 N 4 and Z-scheme CdS@g-C 3 N 4 are analyzed by ultraviolet-visible diffuse reflectance spectroscopy. As Figure 3 shown in 3 a, the absorption edges of CdS, g-C 4 and Z-scheme CdS@g-C 3 N 4 indicate that these prepared catalysts can complete photocatalytic reactions through light response. Between CdS and g-C 3N 4 After forming the heterojunction, Z-scheme CdS@g-C 3 N 4 exhibits better light absorption ability. In Figure 3 b, the band gaps (Eg) of CdS, g-C 3 N 4 and Z-scheme CdS@g-C 3 N 4 are approximately 2.40, 2.70, and 2.42 electron volts, respectively. The conduction bands (CB) and semiconductor types of the materials are confirmed by Mott-Schottky plots. As Figure 3 shown in c and 3d, the plots of CdS and g-C 3 N 4 have positive slopes, indicating that the prepared CdS and g-C 3 N 4 are both n-type semiconductors. The conduction bands of CdS and g-C 3 N 4 are -0.51 and -1.17 volts, respectively (relative to the standard hydrogen electrode NHE, pH = 7). The valence bands of CdS and g-C 3 N 4 are 1.89 and 1.52 volts, respectively.

[0021] In the photocurrent experiment Figure 4 a, photocatalytic response characteristics are observed for all photocatalysts, and the current density is Z-scheme CdS@g-C 3 N 4 > CdS > g-C 3 N 4 . Electrochemical impedance spectroscopy (EIS) is used to analyze the conductivity of CdS, g-C 3 N 4 and Z-scheme CdS@g-C 3 N 4 ( Figure 4 b). Similar to the photocurrent experiment, the conductivity is also Z-scheme CdS@g-C 3 N 4 > CdS > g-C 3 N 4 . The best conductivity of Z-scheme CdS@g-C 3 N 4 may be related to the construction of the built-in electric field, which will facilitate the separation of photo-generated charge carriers in Z-scheme CdS@g-C 3 N 4 . Photoluminescence spectroscopy (PL) is used to study the charge separation and migration efficiency of different photocatalysts. As Figure 4 shown in c, the charge separation and migration efficiency of CdS and g-C 3 N 4It has the maximum PL emission peaks at 433 nm and 456 nm respectively. After the formation of the heterojunction between CdS and g-C 3 N 4 Z-type CdS@g-C 3 N 4 shows a new PL peak at 538 nm, indicating that the two materials are closely combined, and the photo-generated electrons of CdS inhibit the photo-generated holes of g-C 3 N 4 The above electrochemical experiments show that the heterojunction type of CdS@g-C 3 N 4 should operate by the Z-type heterojunction mechanism.

[0022] Example 2 (Reaction reference Table 1, entry 1) In an atmosphere of 1 atm CO 2 CdS (10 mg), toluene (0.2 mmol), K 3 PO 4 (0.4 mmol) and the solvent DMF (2 ml) were placed in a two-necked flask and irradiated with a 10 W blue LED (λ = 460 nm) at room temperature for 24 hours. The conversion of toluene and the selectivity for phenylacetic acid were analyzed by HPLC. The conversion of toluene was 66%, and the selectivity for phenylacetic acid was 97%.

[0023] Example 3 (Reaction reference Table 1, entry 2) In an atmosphere of 1 atm CO 2 g-C 3 N 4 (10 mg), toluene (0.2 mmol), K 3 PO 4 (0.4 mmol) and the solvent DMF (2 ml) were placed in a two-necked flask and irradiated with a 10 W blue LED (λ = 460 nm) at room temperature for 24 hours. The conversion of toluene and the selectivity for phenylacetic acid were analyzed by HPLC. The conversion of toluene was 15%, and the selectivity for phenylacetic acid was 90%.

[0024] Example 4 (Reaction reference Table 1, entry 3) In an atmosphere of 1 atm N 2 CdS (10 mg), toluene (0.2 mmol), K 3 PO 4(0.4 mmol) and the solvent DMF (2 ml) were placed in a two-necked flask and irradiated with a 10 W blue LED (λ = 460 nm) at room temperature for 24 h. The conversion of toluene and the selectivity for phenylacetic acid were analyzed by HPLC. The conversion of toluene was 0%, and the selectivity for phenylacetic acid was 0%.

[0025] Example 5 (reaction reference Table 1, entry 4) Under an atmosphere of 1 atm of N 2 g-C 3 N 4 (10 mg), toluene (0.2 mmol), K 3 PO 4 (0.4 mmol) and the solvent DMF (2 ml) were placed in a two-necked flask and irradiated with a 10 W blue LED (λ = 460 nm) at room temperature for 24 h. The conversion of toluene and the selectivity for phenylacetic acid were analyzed by HPLC. The conversion of toluene was 0%, and the selectivity for phenylacetic acid was 0%.

[0026] Example 6 (reaction reference Table 1, entry 5) Under an atmosphere of 1 atm of CO 2 CdS (10 mg), toluene (0.2 mmol), K 3 PO 4 (0.4 mmol) and the solvent DMF (2 ml) were placed in a two-necked flask and reacted without light irradiation at room temperature for 24 h. The conversion of toluene and the selectivity for phenylacetic acid were analyzed by HPLC. The conversion of toluene was 0%, and the selectivity for phenylacetic acid was 0%.

[0027] Example 7 (reaction reference Table 1, entry 6) Under an atmosphere of 1 atm of CO 2 In the absence of a catalyst, toluene (0.2 mmol), K 3 PO 4 (0.4 mmol) and the solvent DMF (2 ml) were placed in a two-necked flask and irradiated with a 10 W blue LED (λ = 460 nm) at room temperature for 24 h. The conversion of toluene and the selectivity for phenylacetic acid were analyzed by HPLC. The conversion of toluene was 0%, and the selectivity for phenylacetic acid was 0%.

[0028] Example 8 (reaction reference Table 1, entry 7) Under an atmosphere of 1 atm of CO 2In an atmosphere, CdS (10 mg), toluene (0.2 mmol), and the solvent DMF (2 ml) were placed in a two-necked flask and irradiated with a 10 W blue LED (λ = 460 nm) at room temperature for 24 hours. The conversion of toluene and the selectivity for phenylacetic acid were analyzed by HPLC. The conversion of toluene under the condition without base was 0%, and the selectivity for phenylacetic acid was 0%.

[0029] Example 9 (reaction reference Table 1, entry 8) In an atmosphere of 1 atm CO 2 CdS (10 mg), toluene (0.2 mmol), K 3 PO 4 (0.4 mmol) and the solvent DMA (2 ml) were placed in a two-necked flask and irradiated with a 10 W blue LED (λ = 460 nm) at room temperature for 24 hours. The conversion of toluene and the selectivity for phenylacetic acid were analyzed by HPLC. The conversion of toluene was 77%, and the selectivity for phenylacetic acid was 47%.

[0030] Example 10 (reaction reference Table 1, entry 9) In an atmosphere of 1 atm CO 2 CdS (10 mg), toluene (0.2 mmol), K 3 PO 4 (0.4 mmol) and the solvent H 2 O (2 ml) were placed in a two-necked flask and irradiated with a 10 W blue LED (λ = 460 nm) at room temperature for 24 hours. The conversion of toluene and the selectivity for phenylacetic acid were analyzed by HPLC. The conversion of toluene was 0%, and the selectivity for phenylacetic acid was 0%.

[0031] Example 11 (reaction reference Table 1, entry 10) In an atmosphere of 1 atm CO 2 CdS (10 mg), toluene (0.2 mmol), K 3 PO 4 (0.4 mmol) and the solvent DMSO (2 ml) were placed in a two-necked flask and irradiated with a 10 W blue LED (λ = 460 nm) at room temperature for 24 hours. The conversion of toluene and the selectivity for phenylacetic acid were analyzed by HPLC. The conversion of toluene was 22%, and the selectivity for phenylacetic acid was 58%.

[0032] Example 12 (reaction reference Table 1, entry 11) In an atmosphere of 1 atm CO 2In an atmosphere, CdS (10 mg), toluene (0.2 mmol), K 3 PO 4 (0.4 mmol) and the solvent MeCN (2 ml) were placed in a two-necked flask and irradiated with a 10 W blue LED (λ = 460 nm) at room temperature for 24 hours. The conversion of toluene and the selectivity for p-toluic acid were analyzed by HPLC. The conversion of toluene was 31%, and the selectivity for p-toluic acid was 95%.

[0033] Example 13 (reaction reference Table 1, entry 12) In an atmosphere of 1 atm CO 2 In an atmosphere, CdS (10 mg), toluene (0.2 mmol), K 3 PO 4 (0.4 mmol) and the solvent MeCN (2 ml) were placed in a two-necked flask and irradiated with a 30 W blue LED (λ = 460 nm) at room temperature for 24 hours. The conversion of toluene and the selectivity for p-toluic acid were analyzed by HPLC. The conversion of toluene was 64%, and the selectivity for p-toluic acid was 96%.

[0034] Example 14 (reaction reference Table 1, entry 13) In an atmosphere of 1 atm CO 2 In an atmosphere, Z-type CdS@g-C 3 N 4 (10 mg), toluene (0.2 mmol), K 3 PO 4 (0.4 mmol) and the solvent DMF (2 ml) were placed in a two-necked flask and irradiated with a 10 W blue LED (λ = 460 nm) at room temperature for 24 hours. The conversion of toluene and the selectivity for phenylacetic acid were analyzed by HPLC. The conversion of toluene was 99%, and the selectivity for phenylacetic acid was 100%. The Z-type CdS@g-C 3 N 4 was recovered after use, washed, centrifuged, dried and used for the next cycle. During the second, third and fourth cycle experiments, the toluene conversion and selectivity could be maintained at a level above 95%; at the fifth cycle, the conversion was maintained above 90% and the selectivity was maintained above 95%.

[0035] Example 15 (reaction reference Table 1, entry 14) In an atmosphere of 1 atm CO 2 In an atmosphere, Z-type CdS@g-C 3 N 4 (10 mg), toluene (0.2 mmol), K3 PO 4 (0.4 mmol) and the solvent MeCN (2 ml) were placed in a two-necked flask, and the reaction was irradiated with a 30 W blue LED (λ = 460 nm) at room temperature for 24 h. The conversion of toluene and the selectivity for p-toluic acid were analyzed by HPLC. The conversion of toluene was 99%, and the selectivity for p-toluic acid was 100%.

[0036] Example 16 (reaction reference Table 1, entry 15) In an atmosphere of 1 atm CO 2 the Z-type CdS@g-C 3 N 4 (10 mg), toluene (0.2 mmol), K 3 PO 4 (0.4 mmol) and the solvent DMF (2 ml) were placed in a two-necked flask, and the reaction was irradiated with natural light at room temperature for 8 h. The conversion of toluene and the selectivity for phenylacetic acid were analyzed by HPLC. The conversion of toluene was 56%, and the selectivity for phenylacetic acid was 95%.

[0037]

[0038] Example 17 (reaction reference Table 2, entry 2) In an atmosphere of 1 atm CO 2 the Z-type CdS@g-C 3 N 4 (10 mg), benzyl chloride (0.2 mmol), K 3 PO 4 (0.4 mmol) and the solvent DMF (2 ml) were placed in a two-necked flask, and the reaction was irradiated with a 10 W blue LED (λ = 460 nm) at room temperature for 24 h. The conversion of benzyl chloride and the selectivity for phenylacetic acid were analyzed by HPLC. The conversion of benzyl chloride was 96%, and the selectivity for phenylacetic acid was 95%.

[0039] Example 18 (reaction reference Table 2, entry 3) In an atmosphere of 1 atm CO 2 the Z-type CdS@g-C 3 N 4 (10 mg), benzyl bromide (0.2 mmol), K 3 PO 4 (0.4 mmol) and the solvent DMF (2 ml) were placed in a two-necked flask, and the reaction was irradiated with a 10 W blue LED (λ = 460 nm) at room temperature for 24 h. The conversion of benzyl bromide and the selectivity for phenylacetic acid were analyzed by HPLC. The conversion of benzyl bromide was 98%, and the selectivity for phenylacetic acid was 94%.

[0040] Example 19 (Reaction reference Table 2, entry 4) In an atmosphere of 1 atm CO 2 Z-type CdS@g-C 3 N 4 (10 mg), p-xylene (0.2 mmol), K 3 PO 4 (0.4 mmol) and the solvent DMF (2 ml) were placed in a two-necked flask and irradiated with a 10 W blue LED (λ = 460 nm) at room temperature for 24 h. The conversion of p-xylene and the selectivity for p-methylphenylacetic acid were analyzed by HPLC. The conversion of p-xylene was 90%, and the selectivity for p-methylphenylacetic acid was 85%.

[0041] Example 20 (Reaction reference Table 2, entry 5) In an atmosphere of 1 atm CO 2 Z-type CdS@g-C 3 N 4 (10 mg), m-xylene (0.2 mmol), K 3 PO 4 (0.4 mmol) and the solvent DMF (2 ml) were placed in a two-necked flask and irradiated with a 10 W blue LED (λ = 460 nm) at room temperature for 24 h. The conversion of m-xylene and the selectivity for m-methylphenylacetic acid were analyzed by HPLC. The conversion of m-xylene was 85%, and the selectivity for m-methylphenylacetic acid was 81%.

[0042] Example 21 (Reaction reference Table 2, entry 6) In an atmosphere of 1 atm CO 2 Z-type CdS@g-C 3 N 4 (10 mg), o-xylene (0.2 mmol), K 3 PO 4 (0.4 mmol) and the solvent DMF (2 ml) were placed in a two-necked flask and irradiated with a 10 W blue LED (λ = 460 nm) at room temperature for 24 h. The conversion of o-xylene and the selectivity for o-methylphenylacetic acid were analyzed by HPLC. The conversion of o-xylene was 82%, and the selectivity for o-methylphenylacetic acid was 78%.

[0043] Example 22 (Reaction reference Table 2, entry 7) In an atmosphere of 1 atm CO 2 Z-type CdS@g-C 3 N 4(10 mg), mesitylene (0.2 mmol), K 3 PO 4 (0.4 mmol) and the solvent DMF (2 ml) were placed in a two-necked flask and irradiated with a 10 W blue LED (λ = 460 nm) at room temperature for 24 h. The conversion of mesitylene and the selectivity for 3,5-dimethylphenylacetic acid were analyzed by HPLC. The conversion of mesitylene was 78%, and the selectivity for 3,5-dimethylphenylacetic acid was 75%.

[0044] Example 23 (reaction reference Table 2, entry 8) Under an atmosphere of 1 atm CO 2 Z-type CdS@g-C 3 N 4 (10 mg), p-methoxytoluene (0.2 mmol), K 3 PO 4 (0.4 mmol) and the solvent DMF (2 ml) were placed in a two-necked flask and irradiated with a 10 W blue LED (λ = 460 nm) at room temperature for 24 h. The conversion of p-methoxytoluene and the selectivity for p-methoxyphenylacetic acid were analyzed by HPLC. The conversion of p-methylanisole was 77%, and the selectivity for p-methoxyphenylacetic acid was 72%.

[0045] Example 24 (reaction reference Table 2, entry 9) Under an atmosphere of 1 atm CO 2 Z-type CdS@g-C 3 N 4 (10 mg), 4-nitrotoluene (0.2 mmol), K 3 PO 4 (0.4 mmol) and the solvent DMF (2 ml) were placed in a two-necked flask and irradiated with a 10 W blue LED (λ = 460 nm) at room temperature for 24 h. The conversion of 4-nitrotoluene and the selectivity for p-nitrophenylacetic acid were analyzed by HPLC. The conversion of 4-nitrotoluene was 79%, and the selectivity for p-nitrophenylacetic acid was 75%.

[0046] Example 25 (reaction reference Table 2, entry 10) Under an atmosphere of 1 atm CO 2 Z-type CdS@g-C 3 N 4 (10 mg), p-trifluoromethyltoluene (0.2 mmol), K 3 PO 4(0.4 mmol) and the solvent DMF (2 ml) were placed in a two-necked flask, and the reaction was irradiated with a 10 W blue LED (λ = 460 nm) at room temperature for 24 hours. The conversion of trifluoromethyltoluene and the selectivity for phenylacetic acid were analyzed by HPLC. The conversion of trifluoromethyltoluene was 88%, and the selectivity for trifluoromethylphenylacetic acid was 86%.

[0047] Example 26 (refer to Table 2, entry 11) Under an atmosphere of 1 atm CO 2 Z-type CdS@g-C 3 N 4 (10 mg), m-trifluoromethyltoluene (0.2 mmol), K 3 PO 4 (0.4 mmol) and the solvent DMF (2 ml) were placed in a two-necked flask, and the reaction was irradiated with a 10 W blue LED (λ = 460 nm) at room temperature for 24 hours. The conversion of m-trifluoromethyltoluene and the selectivity for phenylacetic acid were analyzed by HPLC. The conversion of m-trifluoromethyltoluene was 83%, and the selectivity for m-trifluoromethylphenylacetic acid was 81%.

[0048] Example 27 (refer to Table 2, entry 12) Under an atmosphere of 1 atm CO 2 Z-type CdS@g-C 3 N 4 (10 mg), o-trifluoromethyltoluene (0.2 mmol), K 3 PO 4 (0.4 mmol) and the solvent DMF (2 ml) were placed in a two-necked flask, and the reaction was irradiated with a 10 W blue LED (λ = 460 nm) at room temperature for 24 hours. The conversion of o-trifluoromethyltoluene and the selectivity for phenylacetic acid were analyzed by HPLC. The conversion of o-trifluoromethyltoluene was 81%, and the selectivity for o-trifluoromethylphenylacetic acid was 77%.

[0049] Example 28 (refer to Table 2, entry 14) Under an atmosphere of 1 atm CO 2 Z-type CdS@g-C 3 N 4 (10 mg), cyclohexane (0.2 mmol), K 3 PO 4 (0.4 mmol) and the solvent DMF (2 ml) were placed in a two-necked flask, and the reaction was irradiated with a 10 W blue LED (λ = 460 nm) at room temperature for 24 hours. The conversion of cyclohexane and the selectivity for cyclohexanecarboxylic acid were analyzed by HPLC. The conversion of cyclohexane was 83%, and the selectivity for cyclohexanecarboxylic acid was 85%.

[0050] Example 29 (Reaction reference Table 2, entry 15) In an atmosphere of 1 atm CO 2 Z-type CdS@g-C 3 N 4 (10 mg), cyclopentane (0.2 mmol), K 3 PO 4 (0.4 mmol) and the solvent DMF (2 ml) were placed in a two-necked flask and irradiated with a 10 W blue LED (λ = 460 nm) at room temperature for 24 h. The conversion of cyclopentane and the selectivity for cyclopentanecarboxylic acid were analyzed by HPLC. The conversion of cyclopentane was 81% and the selectivity for cyclopentanecarboxylic acid was 77%.

[0051] Example 30 (Reaction reference Table 2, entry 16) In an atmosphere of 1 atm CO 2 Z-type CdS@g-C 3 N 4 (10 mg), tetrahydrofuran (0.2 mmol), K 3 PO 4 (0.4 mmol) and the solvent DMF (2 ml) were placed in a two-necked flask and irradiated with a 10 W blue LED (λ = 460 nm) at room temperature for 24 h. The conversion of tetrahydrofuran and the selectivity for tetrahydrofuran-2-carboxylic acid were analyzed by HPLC. The conversion of tetrahydrofuran was 97% and the selectivity for tetrahydrofuran-2-carboxylic acid was 72%.

[0052]

Claims

1. Z-type CdS@g-C3N4 in benzyl and aliphatic sp 3 Application in CH activation and CO2 photocatalytic carboxylation, characterized by : Photocatalysis without sacrificial agents to synthesize benzyl and aliphatic sp 3 CH activation and CO2 carboxylation can produce aromatic acids and alkyl carboxylic acids with increased carbon chains; Preparation of CdS photocatalyst: 10 mmol Cd(NO3)2·4H2O, 30 mmol NH2CSNH2, and 50 mL ethylenediamine were added to a Teflon-lined stainless steel autoclave, and the mixture was reacted at 160°C for 48 hours. After cooling, a yellow solid was separated, washed with H2O / EtOH 5 times, and dried under vacuum to prepare CdS nanorods; Preparation of Z-type CdS@g-C3N4: 200 mg CdS nanorods were added to 30 mL ethanol, stirred for 1 hour, 45 mg melamine was added and stirred for another hour, and the intermediate was obtained by centrifugation and dried under vacuum at 60°C. The intermediate was calcined at 500°C for 2 h under nitrogen to obtain Z-type CdS@g-C3N4; Benzyl and aliphatic sp 3 Preparation of carbon chain-increased acids by CH activation and CO2 carboxylation: In a CO2 atmosphere at 1 atmosphere, 10 mg of catalytic material, 0.2 mmol of substrate, 0.4 mmol of K3PO4 and 2 mL of solvent were placed in a two-necked flask and irradiated with a 10 W blue LED at room temperature for 24 hours; the substrates included toluene, benzyl chloride, benzyl bromide, o-xylene, p-xylene, m-xylene, mesitylene, p-methylanisole, 4-nitrotoluene, 2-methylbenzotrifluoride, 3-methylbenzotrifluoride, 4-methylbenzotrifluoride, cyclohexane, cyclopentane and tetrahydrofuran.

2. Z-type CdS@g-C3N4 in benzyl and aliphatic sp 3 Application in CH activation and CO2 photocatalytic carboxylation, characterized by : The yield of carboxylic acid with increased carbon chain can reach 72%~95%.

3. Z-type CdS@g-C3N4 in benzyl and aliphatic sp 3 Application in CH activation and CO2 photocatalytic carboxylation, characterized by : In a 1 atm CO2 atmosphere, 10 mg Z-type CdS@g-C3N4, 0.2 mmol toluene, 0.4 mmol K3PO4 and 2 ml MeCN solvent were placed in a double-necked flask and irradiated with a 30 W blue LED at room temperature for 24 hours. The conversion rate of toluene was 99% and the selectivity of p-toluic acid was 100%.

4. Z-type CdS@g-C3N4 in benzyl and aliphatic sp 3 Application in CH activation and CO2 photocatalytic carboxylation, characterized by : In a 1 atm CO2 atmosphere, 10 mg Z-type CdS@g-C3N4, 0.2 mmol toluene, 0.4 mmol K3PO4 and 2 ml solvent DMF were placed in a double-necked flask and reacted under natural light at room temperature for 8 hours. The conversion rate of toluene was 56% and the selectivity of phenylacetic acid was 95%.

5. Z-type CdS@g-C3N4 in benzyl and aliphatic sp 3 Application in CH activation and CO2 photocatalytic carboxylation, characterized by : The Z-type CdS@g-C3N4 used for the catalytic conversion of toluene was recovered after use, washed, centrifuged, and dried for the next cycle. During the second, third, and fourth cycle experiments, the toluene conversion rate and selectivity were maintained at above 95%; by the fifth cycle, the conversion rate was maintained at above 90%, and the selectivity was maintained at above 95%.

Images