A Pt / FAPbBr3 photocatalytic material with exposed (100)(111) crystal planes, its preparation method and application
By adding EDTA-4Na and loaded Pt to FAPbBr3 solution, Pt/FAPbBr3 photocatalytic material with exposed (100) (111) crystal planes was prepared, which solved the problem of low catalytic activity of bromide perovskite, realized the efficient coupling of HBr decomposition to produce hydrogen and acetaldehyde oxidation to produce acetic acid, and improved the stability of the catalyst and the photoelectric conversion efficiency.
Patent Information
- Application Number
- CN202610433758.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-04-03
- Publication Date
- 2026-06-05
AI Technical Summary
Existing research shows that bromide perovskites have low catalytic activity for HBr decomposition, and there is insufficient research on the crystal facet control of perovskites. As a result, the hydrogen evolution activity of HBr decomposition is much lower than that of HI decomposition, making it difficult to achieve efficient coupling of hydrogen production and organic oxidation.
By adding tetrasodium ethylenediaminetetraacetate (EDTA-4Na) to a saturated HBr solution of FAPbBr3, FAPbBr3 with exposed (100) and (111) crystal planes was precipitated by co-precipitation and loaded with Pt cocatalyst to improve carrier transport and separation efficiency, thus preparing Pt/FAPbBr3 photocatalytic material with exposed (100) and (111) crystal planes.
The efficient photocatalytic decomposition of HBr to produce hydrogen and the oxidation of acetaldehyde to produce acetic acid were coupled, significantly improving the hydrogen production rate and acetic acid yield. The catalyst exhibited good stability, enhanced light energy conversion efficiency, and the preparation method was simple and low-cost.
Smart Images
Figure CN122141761A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the fields of new energy and photocatalysis technology, specifically relating to a Pt / FAPbBr3 photocatalytic material with exposed (100) (111) crystal planes, its preparation method and application. Background Technology
[0002] In recent years, halide perovskite photocatalysts have been used to decompose hydrogen halides (HX, X=Br). - I - This technology opens up a new pathway for hydrogen production, replacing photocatalytic water splitting. Halide perovskites possess excellent photoelectric properties, including narrow band gaps, high light absorption coefficients, and long carrier diffusion lengths; simultaneously, Br... - / Br2 and I - The oxidation potential of I2 (1.09 V, 0.53 V) is lower than that of water (1.23 V), resulting in more favorable reaction kinetics.
[0003] Current research mainly focuses on the decomposition of iodide perovskites (such as MAPbI3) into hydrogen (HI), and has achieved good results. However, research on the use of bromide perovskites for HBr decomposition is relatively limited. Photocatalytic HBr decomposition can not only realize the conversion of solar energy into hydrogen energy, but also utilize photogenerated holes for the oxidation of acetaldehyde to acetic acid (E2O3). θ (CH3COOH / CH3CHO = 0.6 V), simultaneously obtaining high-value-added chemicals is of great significance for the efficient utilization of solar energy.
[0004] Existing research mainly focuses on enhancing catalytic activity through strategies such as heterostructure construction, compositional regulation, and surface loading. For example, Pt / Ta2O5 and PSS are used to modify MAPbBr3 to promote charge transport. However, the hydrogen evolution activity of HBr decomposition is still much lower than that of HI decomposition, and research on the intrinsic morphology and crystal facet regulation of perovskites is relatively lacking.
[0005] Therefore, developing a strategy to improve the photocatalytic HBr decomposition performance of bromide perovskite through crystal facet engineering and to achieve efficient coupling of hydrogen production and organic oxidation has important research value and application prospects. Summary of the Invention
[0006] To address the aforementioned problems, the present invention aims to provide a Pt / FAPbBr3 photocatalytic material with exposed (100) and (111) crystal planes, its preparation method, and its application. The present invention involves adding tetrasodium ethylenediaminetetraacetate (EDTA-4Na) to a saturated HBr solution of FAPbBr3, thereby co-precipitating FAPbBr3 with exposed (100) and (111) crystal planes. Furthermore, by loading a Pt co-catalyst, the carrier transport and separation efficiency are further improved. This enables a highly efficient photocatalytic decomposition of HBr to produce hydrogen coupled with the oxidation of acetaldehyde to acetic acid. The method is simple to prepare, low in cost, suitable for large-scale production, and exhibits high catalytic activity.
[0007] Specifically, the present invention provides the following technical solution: In a first aspect, the present invention provides a Pt / FAPbBr3 photocatalytic material with exposed (100) (111) crystal planes, the photocatalytic material comprising a FAPbBr3 substrate and Pt nanoparticles supported on the surface of the FAPbBr3 substrate; The FAPbBr3 substrate is a cubic FAPbBr3 crystal with exposed (100) and (111) crystal planes.
[0008] Preferably, in the FAPbBr3 substrate, the exposed area of the (100) crystal plane accounts for 50%~60%, and the exposed area of the (111) crystal plane accounts for 9%~25%; the ratio of the exposed area of the (100) crystal plane to the exposed area of the (111) crystal plane is 2~6.5:1.
[0009] Preferably, the size of the FAPbBr3 substrate is (1~5) µm × (1~5) µm × (5~10) μm; and the particle size of the Pt nanoparticles is 1~100 nm.
[0010] Preferably, the mass ratio of the FAPbBr3 substrate to the Pt nanoparticles is (10~100):1.
[0011] A second aspect of the present invention provides a method for preparing the above-described Pt / FAPbBr3 photocatalytic material with exposed (100) (111) crystal planes, comprising the following steps: A mixture of formamidine acetate and HBr solution was placed in an ice-water bath. The crude product after solvent removal was washed and dried to obtain FABr. Then EDTA-4Na, FABr and PbBr2 were added to HBr solution to obtain FAPbBr3 and its saturated solution. After heating FAPbBr3 and its saturated solution to reach dynamic equilibrium, they were cooled and the precipitate obtained by centrifugation was dried to obtain FAPbBr3 with exposed (100) and (111) crystal planes. Then, FAPbBr3 with exposed (100) (111) crystal planes was added to a saturated HBr solution of FAPbBr3 and stirred to disperse. After adding H2PtCl6•6H2O, a photoreduction reaction was carried out. The precipitate collected by centrifugation was dried to obtain Pt / FAPbBr3 photocatalytic material with exposed (100) (111) crystal planes.
[0012] Preferably, the HBr solution is a 48 wt% HBr aqueous solution, and the ratio of formamidine acetate to HBr solution is 1 mg:(1.3~1.5) mL.
[0013] Preferably, the concentration of EDTA-4Na in the solution is 0.1~0.3 M, and FAPbBr3 and its saturated solution are heated to 60~100℃ and kept at this temperature for 1~2 h until dynamic equilibrium is reached.
[0014] Preferably, in the photoreduction reaction, the light source used is a 300 W full-spectrum xenon lamp, and the reaction time is 0.15~1 h.
[0015] A third aspect of the present invention provides the application of the Pt / FAPbBr3 photocatalytic material with exposed (100) (111) crystal planes as described in the first aspect in the photocatalytic decomposition of HBr to produce hydrogen coupled with the oxidation of acetaldehyde to produce acetic acid.
[0016] A fourth aspect of the present invention provides a method for photocatalytic decomposition of HBr to produce hydrogen coupled with the oxidation of acetaldehyde to produce acetic acid, comprising the following steps: The Pt / FAPbBr3 photocatalytic material with exposed (100) (111) crystal planes as described in the first aspect is dispersed in a saturated HBr solution containing acetaldehyde. The air is removed by vacuuming, and the HBr is photocatalytically decomposed to produce hydrogen, coupled with the oxidation of acetaldehyde to produce acetic acid by irradiation with a light source.
[0017] Preferably, the volume fraction of acetaldehyde in the saturated HBr solution is 0%~2%, excluding 0%, and the ratio of the amount of Pt / FAPbBr3 photocatalytic material with exposed (100) (111) crystal planes to the amount of saturated HBr solution containing acetaldehyde is (1~10) mg: 1 mL.
[0018] One or more embodiments of the present invention have at least the following beneficial effects: (1) This invention achieves for the first time the controllable co-exposure of (100) and (111) crystal planes in FAPbBr3 perovskite, breaking the limitation of mainly exposing (110) crystal planes in conventional synthesis. Furthermore, by adjusting the crystal plane ratio, crystal plane-dependent carrier separation and reactive site optimization are achieved.
[0019] (2) In the coprecipitation synthesis of FAPbBr3, the present invention introduces EDTA-4Na as a crystal facet regulator to induce preferential exposure of (100) and (111) crystal faces in HBr saturated solution. This method achieves precise control of the crystal facet exposure ratio by controlling the concentration of EDTA-4Na (0.1~0.3 M), which solves the problem of uncontrollable crystal faces in traditional synthesis. At the same time, Pt nanoparticles are loaded onto the FAPbBr3 surface with specific crystal faces exposed by photoreduction method, forming a crystal facet-co-catalyst synergistic interface.
[0020] (3) In this invention, Pt / FAPbBr3 material with exposed (100) and (111) crystal planes is applied to a coupled reaction system of HBr decomposition to produce hydrogen and acetaldehyde oxidation to produce acetic acid, achieving a hydrogen production rate as high as 1033.13 μmol·h. -1 Acetic acid yield reached 1017.2 μmol·h⁻¹ -1 The performance was improved by more than 21 times compared to the sample without controlled crystal planes, and the catalyst showed no significant performance degradation in 5 cycles (15 hours in total), demonstrating good stability.
[0021] (4) The preparation method involved in this invention is simple, the reaction conditions are mild, the cost is low, and it can be prepared on a large scale. The resulting catalyst structure significantly improves the separation efficiency of photogenerated carriers, which is manifested by a significant reduction in fluorescence lifetime (from 55 ns to 1.486 ns) and an increase in photocurrent density. At the same time, the apparent quantum efficiency reaches 30.62% and 31.78% at wavelengths of 450 nm and 520 nm, respectively, showing excellent light energy conversion efficiency. Attached Figure Description
[0022] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.
[0023] Figure 1 The images shown are characterization diagrams of the photocatalytic materials prepared in the embodiments and comparative examples of the present invention. (a) is the XRD pattern of 0.2M EDTA / 1.5%Pt / FPB prepared in Example 1, 1.5%Pt / FPB-(110) prepared in Comparative Example 1, and FPB-(110) prepared in Comparative Example 2; (b) is the SEM image of FPB-(110) prepared in Comparative Example 2; (c) is the SEM image of 0.2M EDTA / 1.5%Pt / FPB prepared in Example 1; (d) is the TEM image of 0.2M EDTA / 1.5%Pt / FPB prepared in Example 1; and (e) is the EDS mapping diagram of 0.2M EDTA / 1.5%Pt / FPB prepared in Example 1. Figure 2The XRD patterns of 0.2M EDTA / 1.5%Pt / FPB, 0.1M EDTA / 1.5%Pt / FPB and 0.2M EDTA / 1.5%Pt / FPB in Examples 1-3 of this invention are shown. Figure 3 SEM images of FPB-(110), 0.05M EDTA / 1.5%Pt / FPB and 0.35M EDTA / 1.5%Pt / FPB in Comparative Examples 2-4 of this invention; Figure 4 The XPS spectra of 0.2M EDTA / 1.5%Pt / FPB prepared in Example 1 of the present invention and 1.5%Pt / FPB-(110) prepared in Comparative Example 1 are shown, wherein (a) is the Pb 4f spectrum of 1.5%Pt / FPB-(110) and 0.2M EDTA / 1.5%Pt / FPB, and (b) is the Br 3d spectrum of 1.5%Pt / FPB-(110) and 0.2M EDTA / 1.5%Pt / FPB. Figure 5 The following are performance test diagrams of the photocatalytic material prepared in Example 1 of the present invention, wherein (a) is a reaction stability diagram and (b) is an AQE test calculation diagram; Figure 6 The images show the optical performance test results of the photocatalytic materials prepared in Example 1 and Comparative Example 1 of this invention. (a) is the single-particle fluorescence image of 1.5%Pt / FPB-(110), (b) is the single-particle fluorescence image of 0.2M EDTA / 1.5%Pt / FPB, (c) is the fluorescence intensity image of 1.5%Pt / FPB-(110) and 0.2M EDTA / 1.5%Pt / FPB, (d) is the lifetime image of 1.5%Pt / FPB-(110) and 0.2M EDTA / 1.5%Pt / FPB, and (e) is the transient photoresponse image of 1.5%Pt / FPB-(110) and 0.2M EDTA / 1.5%Pt / FPB. Detailed Implementation
[0024] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.
[0025] The present invention will be further described in detail below with reference to specific embodiments. It should be noted that the specific embodiments are explanations of the present invention and not limitations thereof.
[0026] Example 1: This embodiment provides a Pt / FAPbBr3 photocatalytic material with exposed (100) (111) crystal planes and its preparation method. The preparation method specifically includes the following steps: (1) 10 g of formamidine acetate (CH4N2·C2H4O2) and 14 mL of HBr (48 wt% aqueous solution) were mixed in an ice-water bath and stirred for 2 h. The solvent was removed by rotary evaporation at 60 °C. The crude product was recrystallized with ethanol and diethyl ether solution, washed three times with diethyl ether, and the resulting white powder of formamidine bromide (FABr) was finally dried in a vacuum oven at 65 °C for 6 h.
[0027] (2) Excess FABr and PbBr2 were added to HBr solution at a stoichiometric ratio of 1:1 (in order to ensure that FABr and PbBr2 react in a stoichiometric ratio of 1:1 to generate FAPbBr3, excess FABr and PbBr2 were actually added). A certain mass of EDTA-4Na was added so that the concentration of EDTA-4Na in the HBr solution after adding FABr and PbBr2 was 0.2 M, thus preparing FAPbBr3 with exposed (100)(111) crystal planes and its saturated solution. The solution containing the FAPbBr3 precursor with exposed (100)(111) crystal planes was heated to 95℃ and held for 1 h to reach dynamic equilibrium, and then cooled to room temperature. After natural cooling, the FPB-(100)(111) precipitate and saturated solution (supernatant) were separated by centrifugation, and the precipitate was dried in a vacuum oven at 60℃ for 6 h.
[0028] (3) 100 mg FPB-(100)(111) was added to 10 mL of saturated HBr solution of FAPbBr3 (FAPbBr3 was first dissolved in HBr solution until saturated, and then the precipitate was removed by filtration to obtain saturated HBr solution of FAPbBr3) and ultrasonically stirred to disperse evenly. 1.5 mg H2PtCl6·6H2O was added to the above solution and stirred for 30 min, and then irradiated under a 300 W xenon lamp (full spectrum) for 0.5 h for photoreduction. The Pt / FAPbBr3 photocatalyst precipitate with exposed (100)(111) crystal faces was collected by centrifugation and dried in a vacuum oven at 60 °C for 6 h to obtain 0.2 M EDTA / 1.5% Pt / FPB.
[0029] Example 2: The difference between this embodiment and Example 1 is that the concentration of EDTA-4Na in the solution is 0.1 M, while the content of other components and the preparation method are the same as in Example 1 (0.1 M EDTA / 1.5% Pt / FPB).
[0030] Example 3: The difference between this embodiment and Example 1 is that the concentration of EDTA-4Na in the solution is 0.3 M, while the content of other components and the preparation method are the same as in Example 1 (0.3M EDTA / 1.5%Pt / FPB).
[0031] Example 4: The difference between this embodiment and Example 1 is that the amount of H2PtCl6·6H2O added is 1 mg, while the content of other components and the preparation method are the same as in Example 1 (0.2M EDTA / 1%Pt / FPB).
[0032] Example 5: The difference between this embodiment and Example 1 is that the amount of H2PtCl6·6H2O added is 2 mg, while the content of other components and the preparation method are the same as in Example 1 (0.2M EDTA / 2%Pt / FPB).
[0033] Comparative Example 1: The difference between this comparative example and Example 1 is that EDTA-4Na was not added in step (2). The specific preparation steps are as follows: (1) 10 g of (CH4N2·C2H4O2) and 14 mL of HBr (48 wt% aqueous solution) were mixed in an ice-water bath and stirred for 2 h. The solvent was removed by rotary evaporation at 60 °C. The crude product was recrystallized with ethanol and diethyl ether solution, washed three times with diethyl ether, and the resulting white FABr powder was dried in a vacuum oven at 65 °C for 6 h.
[0034] (2) Excess FABr and PbBr2 were added to HBr solution at a stoichiometric ratio of 1:1 (in fact, excess FABr and PbBr2 were added to ensure that FABr and PbBr2 reacted at a stoichiometric ratio of 1:1 to generate FAPbBr3), thus preparing FAPbBr3 and its saturated solution. The solution of the FAPbBr3 precursor was heated to 95℃ and held for 1 h to reach dynamic equilibrium, and then cooled to room temperature. After natural cooling, the FAPbBr3 precipitate and saturated solution were separated by centrifugation, and the precipitate was dried in a vacuum oven at 60℃ for 6 h.
[0035] (3) 100 mg FAPbBr3 was added to 10 mL of saturated HBr solution of FAPbBr3 and ultrasonically and stirred to disperse evenly. 1.5 mg H2PtCl6·6H2O was added to the above solution and stirred for 30 min, followed by photoreduction under a 300 W xenon lamp (full spectrum) for 0.5 h. The Pt / FAPbBr3 photocatalyst precipitate was collected by centrifugation and dried in a vacuum oven at 60 °C for 6 h to obtain 1.5% Pt / FPB-(110).
[0036] Comparative Example 2: The difference between this comparative example and Example 1 is that EDTA-4Na was not added in step (2); and H2PtCl6·6H2O was not added in step (3). The specific preparation steps are as follows: (1) 10 g of (CH4N2·C2H4O2) and 14 mL of HBr (48 wt% aqueous solution) were mixed in an ice-water bath and stirred for 2 h. The solvent was removed by rotary evaporation at 60 °C. The crude product was recrystallized with ethanol and diethyl ether solution, washed three times with diethyl ether, and the resulting white FABr powder was dried in a vacuum oven at 65 °C for 6 h.
[0037] (2) Excess FABr and PbBr2 were added to HBr solution at a stoichiometric ratio of 1:1 (in order to ensure that FABr and PbBr2 react in a stoichiometric ratio of 1:1 to generate FAPbBr3, excess FABr and PbBr2 were actually added) to prepare FAPbBr3 and its saturated solution. The solution of the FAPbBr3 precursor was heated to 95℃ and held for 1 h to reach dynamic equilibrium, and then cooled to room temperature. After natural cooling, the FAPbBr3 precipitate and saturated solution were separated by centrifugation, and the precipitate was dried in a vacuum oven at 60℃ for 6 h to obtain FPB-(110).
[0038] Comparative Example 3: The difference between this comparative example and Example 1 is that the concentration of EDTA-4Na in the solution is 0.05 M, while the content of other components and the preparation method are the same as in Example 1 (0.05M EDTA / 1.5%Pt / FPB).
[0039] Comparative Example 4: The difference between this comparative example and Example 1 is that the concentration of EDTA-4Na in the solution is 0.35 M, while the content of other components and the preparation method are the same as in Example 1 (0.35M EDTA / 1.5%Pt / FPB).
[0040] Comparative Example 5: The difference between this comparative example and Example 1 is that in step (2), H2PtCl6·6H2O is mixed in using a "one-pot method". The specific preparation steps are as follows: (1) 10 g of formamidine acetate (CH4N2·C2H4O2) and 14 mL of HBr (48 wt% aqueous solution) were mixed in an ice-water bath and stirred for 2 h. The solvent was removed by rotary evaporation at 60 °C. The crude product was recrystallized with ethanol and diethyl ether solution, washed three times with diethyl ether, and the resulting white powder of formamidine bromide (FABr) was finally dried in a vacuum oven at 65 °C for 6 h.
[0041] (2) Excess FABr and PbBr2 were added to HBr solution at a stoichiometric ratio of 1:1 (resulting in 100 mg of FAPbBr3 precipitate), and a certain mass of EDTA-4Na was added to make the concentration of EDTA-4Na in HBr solution 0.2 M after the addition of FABr and PbBr2. Then, 1.5 mg of H2PtCl6·6H2O was added to the above solution and stirred for 30 min. Subsequently, the solution was irradiated with a 300 W xenon lamp (full spectrum) for 0.5 h for photoreduction. The Pt / FAPbBr3 photocatalyst precipitate exposed on the (100) (111) crystal plane was collected by centrifugation and dried in a vacuum oven at 60 °C for 6 h to obtain 0.2 M EDTA-1.5% Pt / FPB.
[0042] Experimental Example 1: This experimental example performs structural analysis on the photocatalytic materials prepared in the examples and comparative examples. like Figure 1 As shown in (a), the XRD pattern indicates that the FPB-(110) obtained in Comparative Example 2 is cubic and has good crystallinity. No peak shift occurred after Pt loading. The XRD pattern of 0.2M EDTA / 1.5%Pt / FPB obtained under EDTA-4Na showed a clear (111) crystal plane peak. Meanwhile, as shown in (a), Figure 2 As shown, the ratio of the (100) crystal plane to the (111) crystal plane in the photocatalytic materials prepared in Examples 1-3 is 2.625:1, 6.3:1, and 2.28:1, respectively; Figure 1 As shown in the SEM image of (b) in Comparative Example 2, the FPB-(110) particles obtained are quasi-dodecahedral in shape, mainly composed of (110) crystal planes, with a particle size of 6 µm; Figure 3 As shown in the SEM image of (b) in the comparison examples, the photocatalyst materials prepared in Examples 1, 3-4, when EDTA-4Na was not added or the concentration of EDTA-4Na was too low or too high, could not expose the (100) and (111) crystal planes. Figure 1 The SEM image in (c) shows that the product obtained under the action of EDTA-4Na is cubic in shape, with dimensions of 4 µm × 4 μm × 10 µm (length × width × height); Figure 1 As shown in (d), two distinct lattice fringes of 0.2386 nm and 0.2998 nm, belonging to Pt and FAPbBr3 respectively, were clearly observed in 0.2M EDTA / 1.5%Pt / FPB, confirming the formation of the Pt / FAPbBr3 composite material after the photoreduction loading process; Figure 1 As shown in (e) in the EDS mapping diagram, the surface of the FAPbBr3 particles of the photocatalytic material is partially covered with Pt.
[0043] like Figure 3As shown, the SEM images of FPB-(110), 0.05M EDTA / 1.5%Pt / FPB and 0.35M EDTA / 1.5%Pt / FPB in Comparative Examples 2 to 4 of this invention are shown. It can be seen that the (100) and (111) crystal planes were not exposed.
[0044] Furthermore, the electronic states and atomic environment of Pt atoms on the FAPbBr3 support were further investigated using X-ray photoelectron spectroscopy (XPS): like Figure 4 As shown in (a) and (b), the high-resolution XPS spectra of the elements in the 1.5%Pt / FPB-(110) and 0.2M EDTA / 1.5%Pt / FPB composites reveal a significant positive shift in the spectra of Pb 4f and Br 3d after the morphology change, by 0.29 eV and 0.35 eV respectively compared to the original 1.5%Pt / FPB-(110) sample. These results indicate that electrons in the 0.2M EDTA / 1.5%Pt / FPB with (100) and (111) crystal planes are more biased towards anchored Pt species, which will greatly promote the H* reduction reaction at Pt sites during subsequent photocatalysis.
[0045] Experimental Example 1: This experimental example tests the photocatalytic decomposition of HBr to produce hydrogen coupled with the oxidation of acetaldehyde to acetic acid using the photocatalytic materials prepared in the examples and comparative examples: The photocatalytic reaction was carried out in a 125 mL quartz binaural reactor connected to a 15°C cooling circulating water system. 100 mg of the photocatalyst materials prepared in the examples and comparative examples were immersed in 10 mL of a mixed HBr / acetaldehyde solution. The system was evacuated for 30 minutes to ensure complete removal of air, and then irradiated from the top surface with a 300 W xenon lamp (PLS-SXE300D, Beijing Pofilai Technology Co., Ltd.) equipped with an AM1.5G filter (simulating sunlight irradiation (AM1.5G, 100 mW cm⁻¹). 2 The separated gases were analyzed by gas chromatography (GC-7290, TCD, with Ar as the carrier gas), and the oxidation products of acetaldehyde were detected by ion chromatography. Specific test results are shown in Table 1. Table 1
[0046] Analysis of the data in Table 1 shows that, compared to Example 1, the concentration of EDTA-4Na in the solution of Examples 2 and 3 changed, which altered the ratio of exposed (100) / (111) crystal faces. An excessive proportion of (100) crystal faces enhanced the stability of the catalyst but reduced the number of active sites, while an insufficient proportion of (100) crystal faces reduced the stability of the catalyst and also affected the photocatalytic activity. This demonstrates that there is an optimal exposure ratio for (100) / (111) crystal faces. In Examples 4 and 5, the Pt loading changed. Too low a Pt loading resulted in too few catalytic sites, while too high a Pt loading caused Pt particles to agglomerate, affecting the catalytic activity.
[0047] Compared to Example 1, Comparative Example 2 is a pure FAPbBr3 sample without Pt loading and without exposed (100) (111) crystal planes, which can be considered as the original activity data. The hydrogen evolution activity of FPB-(110) in HBr / acetaldehyde solution is 48 μmol h⁻¹. 1 The yield of acetic acid was 45 μmol / h. 1 The hydrogen evolution activity of 0.2M EDTA / 1.5%Pt / FPB in HBr / acetaldehyde solution reached 1033.13 μmol h⁻¹. 1 The yield of acetic acid was 1017.2 μmol / h. 1 It increased by more than 21 times.
[0048] Compared to Example 1, in Comparative Examples 1, 3 and 4, the (100) (111) crystal planes could not be exposed if EDTA-4Na was not added or if the concentration of EDTA-4Na was too low or too high. This indicates that exposing the (100) (111) crystal planes can enhance the photocatalytic performance of FAPbBr3 perovskite.
[0049] Compared to Example 1, Comparative Example 5 uses a "one-pot" method to add the raw materials to the solution together, which is not conducive to the interaction between EDTA-4Na and FAPbBr3 and the loading of Pt particles on FAPbBr3, resulting in a decrease in catalytic activity.
[0050] At the same time, such as Figure 5 As shown in (a), 0.2M EDTA / 1.5%Pt / FPB exhibited good long-term stability in hydrogen evolution coupled with acetaldehyde oxidation, with no significant decrease after five repeated cycles (3 h each). Figure 5 As shown in (b), high apparent quantum efficiencies of 30.62% and 31.78% were obtained at wavelengths of 450 nm and 520 nm, respectively.
[0051] In addition, single-particle photoluminescence (PL) microscopy was used to study charge dynamics and explore the role of exposing (100) and (111) crystal planes in improving charge separation: like Figure 6 The inset in (a) shows a bright PL image of 1.5% Pt / FPB-(110), compared to 0.2 MEDTA / 1.5% Pt / FPB ( Figure 6 The inset in (b) shows a significant decrease in brightness, indicating PL quenching. Therefore, the PL intensity of 1.5% Pt / FPB-(110) in the single-particle PL spectrum ( Figure 6 (c) in the figure corresponds to points 1, 2, and 3 in the inserted figure. The concentration of 0.2M EDTA / 1.5%Pt / FPB is stronger. Figure 6 The PL spectra obtained from points 4, 5, and 6 in (c) are much weaker.
[0052] like Figure 6 As shown in (d), the fluorescence lifetime spectrum indicates that 1.5%Pt / FPB-(110) has a longer average fluorescence lifetime of 55 ns. However, after exposing the (100)(111) crystal plane, the fluorescence lifetime of 0.2M EDTA / 1.5%Pt / FPB decreases to 1.486 ns. This indicates that exposing the (100)(111) crystal plane accelerates the separation of photogenerated carriers in the FAPbBr3 perovskite, thereby improving the performance of photocatalytic cracking of HBr hydrogen evolution coupled with acetaldehyde oxidation to acetic acid.
[0053] Photoelectrochemical tests were performed on 1.5% Pt / FPB-(110) and 0.2 M EDTA / 1.5% Pt / FPB, such as... Figure 6 As shown in (e), 0.2M EDTA / 1.5%Pt / FPB exhibits a higher photocurrent density compared to 1.5%Pt / FPB-(110). The FAPbBr3 carriers exposed on the (100) and (111) crystal planes have higher separation efficiency, thereby enhancing the activity of the hydrogen evolution coupled acetic acid synthesis reaction.
[0054] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A Pt / FAPbBr3 photocatalytic material with exposed (100) (111) crystal planes, characterized in that, The photocatalytic material comprises a FAPbBr3 substrate and Pt nanoparticles supported on the surface of the FAPbBr3 substrate; The FAPbBr3 substrate is a cubic FAPbBr3 crystal with exposed (100) and (111) crystal planes.
2. The Pt / FAPbBr3 photocatalytic material with exposed (100) (111) crystal planes as described in claim 1, characterized in that, In the FAPbBr3 substrate, the exposed area of the (100) crystal plane accounts for 50%~60%, and the exposed area of the (111) crystal plane accounts for 9%~25%; the ratio of the exposed area of the (100) crystal plane to the exposed area of the (111) crystal plane is 2~6.5:
1.
3. The Pt / FAPbBr3 photocatalytic material with exposed (100) (111) crystal planes as described in claim 1, characterized in that, The FAPbBr3 substrate has a size of (1~5) µm × (1~5) µm × (5~10) μm; the Pt nanoparticles have a particle size of 1~100 nm.
4. The Pt / FAPbBr3 photocatalytic material with exposed (100) (111) crystal planes as described in claim 1, characterized in that, The mass ratio of the FAPbBr3 substrate to the Pt nanoparticles is (10~100):
1.
5. A method for preparing a Pt / FAPbBr3 photocatalytic material with exposed (100) (111) crystal planes as described in any one of claims 1 to 4, characterized in that, Includes the following steps: A mixture of formamidine acetate and HBr solution was placed in an ice-water bath. The crude product after solvent removal was washed and dried to obtain FABr. Then EDTA-4Na, FABr and PbBr2 were added to HBr solution to obtain FAPbBr3 and its saturated solution. After heating FAPbBr3 and its saturated solution to reach dynamic equilibrium, they were cooled and the precipitate obtained by centrifugation was dried to obtain FAPbBr3 with exposed (100) and (111) crystal planes. Then, FAPbBr3 with exposed (100) (111) crystal planes was added to a saturated HBr solution of FAPbBr3 and stirred to disperse. After adding H2PtCl6•6H2O, a photoreduction reaction was carried out. The precipitate collected by centrifugation was dried to obtain Pt / FAPbBr3 photocatalytic material with exposed (100) (111) crystal planes.
6. The preparation method according to claim 5, characterized in that, The HBr solution is a 48 wt% HBr aqueous solution, and the ratio of formamidine acetate to HBr solution is 1 mg:(1.3~1.5) mL.
7. The preparation method according to claim 5, characterized in that, The concentration of EDTA-4Na in the solution is 0.1~0.3 M. FAPbBr3 and its saturated solution are heated to 60~100℃ and kept at this temperature for 1~2 h until dynamic equilibrium is reached. Preferably, in the photoreduction reaction, the light source used is a 300 W full-spectrum xenon lamp, and the reaction time is 0.15~1h.
8. The application of a Pt / FAPbBr3 photocatalytic material with exposed (100) (111) crystal planes as described in any one of claims 1 to 4 in the photocatalytic decomposition of HBr to produce hydrogen coupled with the oxidation of acetaldehyde to produce acetic acid.
9. A method for photocatalytic decomposition of HBr to produce hydrogen coupled with the oxidation of acetaldehyde to produce acetic acid, characterized in that, Includes the following steps: The Pt / FAPbBr3 photocatalytic material with exposed (100) (111) crystal planes as described in any one of claims 1 to 4 is dispersed in a saturated HBr solution containing acetaldehyde, the air is removed by vacuuming, and the HBr is photocatalytically decomposed to produce hydrogen and coupled with the oxidation of acetaldehyde to produce acetic acid by irradiation with a light source.
10. The method as described in claim 9, characterized in that, The volume fraction of acetaldehyde in the saturated HBr solution is 0%~2%, excluding 0%, and the ratio of the amount of Pt / FAPbBr3 photocatalytic material with exposed (100) (111) crystal planes to the amount of saturated HBr solution containing acetaldehyde is (1~10) mg:1 mL.