A d-PtNi / MAPbI3 photocatalyst and its preparation method and application

Abstract

The present invention belongs to the field of new energy and photocatalytic technology, and specifically relates to a d-PtNi / MAPbI3 photocatalyst and its preparation method and application. A platinum source, a nickel source, NaBH4, PVP and ethylenediamine are uniformly mixed and then subjected to a solvent thermal reaction to obtain a PtNi alloy. The PtNi alloy is added to hydroiodic acid for a dealloying reaction to obtain d-PtNi; d-PtNi and MAPbI3 are added to a saturated MAPbI3 solution, stirred and subjected to a photodeposition reaction to obtain a d-PtNi / MAPbI3 photocatalyst. The d-PtNi / MAPbI3 photocatalyst has excellent photogenerated carrier separation ability, effectively improving the photocatalytic hydrogen production performance and cycle stability. At the same time, the low loading of d-PtNi reduces the preparation cost.

Description

Technical Field

[0001] The present invention belongs to the field of new energy and photocatalytic technology, and specifically relates to a d-PtNi / MAPbI3 photocatalyst and a preparation method and application thereof. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art.

[0003] Hydrogen is a clean secondary energy source with advantages such as high energy density, zero pollution, and zero carbon emissions. It is considered one of the most promising energy carriers. Photocatalytic hydrogen production, which uses solar energy as a power source, offers a welcome alternative to traditional hydrogen production. However, the slow reaction rate and poor stability of semiconductor photocatalysts have limited the development of photocatalytic hydrogen production technology. There is still a need to develop efficient and stable photocatalysts to meet the requirements of future practical applications.

[0004] Organic-inorganic hybrid perovskites have suitable and adjustable band gaps, high light absorption coefficients, wide range of light collection and excellent charge carrier mobility, which are beneficial to the conversion of solar energy into chemical energy. However, perovskites are unstable in water and require a solution containing the corresponding halogen element as a reaction solution to maintain stability during the photocatalytic process. In addition, their hydrogen production efficiency is still limited by their intrinsic activity. Constructing heterojunctions and loading co-catalysts can effectively improve the hydrogen production capacity of organic-inorganic hybrid perovskite photocatalysts, among which Pt is the most effective co-catalyst in hydrogen production. However, the shortage of Pt resources and its high price make it difficult to apply it to industrial production. Other co-catalysts are difficult to simultaneously meet the requirements of stability in strong acid and high hydrogen production activity. Summary of the Invention

[0005] To address the deficiencies of the prior art, the present invention provides a d-PtNi / MAPbI3 photocatalyst, its preparation method, and application. PtNi alloy nanoparticles were synthesized using a solvothermal co-reduction method. These PtNi alloy nanoparticles were dealloyed in HI acid and then deposited onto MAPbI3 perovskite to form the d-PtNi / MAPbI3 photocatalyst. The d-PtNi / MAPbI3 photocatalyst exhibits excellent separation of photogenerated charge carriers, effectively improving photocatalytic hydrogen production performance and cyclic stability. The low d-PtNi loading reduces preparation costs.

[0006] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0007] In a first aspect, a method for preparing a d-PtNi / MAPbI3 photocatalyst comprises the following steps:

[0008] S1, mixing platinum source, nickel source, NaBH4, PVP and ethylenediamine uniformly and performing a solvothermal reaction to obtain a PtNi alloy, and adding the PtNi alloy to hydroiodic acid for a dealloying reaction to obtain d-PtNi;

[0009] S2. Add d-PtNi and MAPbI3 into a saturated MAPbI3 solution, stir, and then perform a photodeposition reaction to obtain a d-PtNi / MAPbI3 photocatalyst.

[0010] Preferably, in step S1, the platinum source includes platinum acetylacetonate, the nickel source includes nickel acetylacetonate, and the ratio of the platinum source, the nickel source, NaBH4 and PVP is (3 mmol): (3 mmol): (95-105 mmol): (95-105 g).

[0011] Preferably, in step S1, the solvent thermal reaction is carried out at 150-170° C. for 18-24 hours, and the dealloying reaction time is 1-3 hours.

[0012] Preferably, in step S2, the mass of d-PtNi is 1% to 5% of the mass of MAPbI3.

[0013] Preferably, in step S2, the photodeposition reaction time is 20 to 40 minutes.

[0014] Preferably, the method also includes the preparation of MAPbI3 and MAPbI3 saturated solution:

[0015] Lead iodide is dissolved in a mixed solution of hydroiodic acid and hypophosphorous acid. After the lead iodide is completely dissolved, methylamine iodide is added. After stirring for reaction, solid-liquid separation is performed to obtain MAPbI3 and a saturated solution of MAPbI3.

[0016] More preferably, the volume ratio of hydroiodic acid to hypophosphorous acid is (3.5-4.5):1, and the molar ratio of lead iodide to methylamine iodide is 1:(0.99-1.01).

[0017] More preferably, the stirring reaction time is 1 to 3 hours.

[0018] In a second aspect, a d-PtNi / MAPbI3 photocatalyst is obtained by the preparation method described in the first aspect.

[0019] In the third aspect, the application of the d-PtNi / MAPbI3 photocatalyst described in the first aspect in photocatalytic cracking of HI to produce hydrogen.

[0020] The beneficial effects achieved by one or more technical solutions of the present invention are as follows:

[0021] As a co-catalyst, d-PtNi effectively improves the separation ability of photogenerated carriers, so that the d-PtNi / MAPbI3 photocatalyst has excellent photocatalytic hydrogen production performance and cyclic stability. Compared with unde-alloyed PtNi and Pt co-catalyst, d-PtNi can further improve the catalytic performance of the photocatalyst, while achieving cost reduction and performance improvement. The hydrogen production rate of the d-PtNi / MAPbI3 photocatalyst can reach 5644μmol / h; its corresponding solar energy to hydrogen energy conversion efficiency (i.e., photoinduced hydroiodic acid decomposition efficiency) reaches 6.15%. In addition, the hydrogen production performance of the d-PtNi / MAPbI3 photocatalyst did not decrease significantly after a 24-hour cycle test (one cycle every 3 hours, a total of 8 cycles), and the material structure and morphology did not change significantly.

[0022] The synthesis conditions of d-PtNi / MAPbI3 photocatalyst are mild, the preparation method is simple, and the cost is low, and it has broad commercial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0024] Figure 1 XRD patterns of (a) d-PtNi, PtNi in Example 1 and Pt in Comparative Example 1, and (b) MAPbI3, 3 wt% d-PtNi / MAPbI3 in Example 1 and 3 wt% PtNi / MAPbI3 in Comparative Example 2;

[0025] Figure 2 TEM image of d-PtNi in Example 1;

[0026] Figure 3 TEM image of 3 wt% d-PtNi / MAPbI3 in Example 1, (b) is a partial enlarged view of (a);

[0027] Figure 4 Comparison of the photocatalytic cracking HI hydrogen production performance of (a) 3 wt% d-PtNi / MAPbI3 in Example 1, 1 wt% d-PtNi / MAPbI3 in Example 2, and 5 wt% d-PtNi / MAPbI3 in Example 3, and (b) MAPbI3 and 3 wt% d-PtNi / MAPbI3 in Example 1, 3 wt% Pt / MAPbI3 in Comparative Example 1, and 3 wt% PtNi / MAPbI3 in Comparative Example 2;

[0028] Figure 5 The photocatalytic cracking HI hydrogen production cycle stability of 3wt% d-PtNi / MAPbI3 in Example 1;

[0029] Figure 6 (a) Photocurrent density and (b) impedance spectrum of MAPbI3 and 3wt% d-PtNi / MAPbI3 in Example 1 and 3wt% PtNi / MAPbI3 in Comparative Example 2. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments and comparative examples.

[0031] Example 1

[0032] Place 40 mL of hydroiodic acid (48% aqueous solution) and 10 mL of hypophosphorous acid (50% aqueous solution) in a 100 mL beaker, add 14 g of lead iodide and continue stirring. After it is completely dissolved, slowly add 4.825 g of methylamine iodide. After stirring for 2 hours, centrifuge to separate the black powder and solution. The obtained MAPbI3 saturated solution is retained, and the black powder is MAPbI3, which is vacuum dried at 60°C for later use.

[0033] 0.12 mmol of platinum acetylacetonate, 0.12 mmol of nickel acetylacetonate, 4 mmol of NaBH4, and 4 g of PVP were added to a reactor containing 20 mL of ethylenediamine and stirred until dissolved. The mixture was solvothermally reacted at 160°C for 20 h and centrifuged to dry to obtain PtNi alloy powder. The PtNi alloy powder was placed in 2 mL of HI acid and dealloyed for 2 h before centrifugation to obtain d-PtNi.

[0034] 250 mg of MAPbI3 was dispersed in a saturated MAPbI3 solution, 7.5 mg of d-PtNi was added, and the mixture was irradiated under simulated sunlight with a 300 W xenon lamp as the light source for 30 minutes. The solid product was collected by centrifugation and vacuum dried at 60°C. The obtained d-PtNi / MAPbI3 photocatalyst was recorded as 3 wt% d-PtNi / MAPbI3.

[0035] Example 2

[0036] Place 40 mL of hydroiodic acid (48% aqueous solution) and 10 mL of hypophosphorous acid (50% aqueous solution) in a 100 mL beaker, add 14 g of lead iodide and continue stirring. After it is completely dissolved, slowly add 4.825 g of methylamine iodide. After stirring for 2 hours, centrifuge to separate the black powder and solution. The obtained MAPbI3 saturated solution is retained, and the black powder is MAPbI3, which is vacuum dried at 60°C for later use.

[0037] 0.12 mmol of platinum acetylacetonate, 0.12 mmol of nickel acetylacetonate, 4 mmol of NaBH4, and 4 g of PVP were added to a reactor containing 20 mL of ethylenediamine and stirred until dissolved. The mixture was solvothermally reacted at 160°C for 20 h and centrifuged to dry to obtain PtNi alloy powder. The PtNi alloy powder was placed in 2 mL of HI acid and dealloyed for 2 h before centrifugation to obtain d-PtNi.

[0038] 250 mg of MAPbI3 was dispersed in a saturated MAPbI3 solution, 2.5 mg of d-PtNi was added, and the mixture was irradiated under simulated sunlight with a 300 W xenon lamp as the light source for 30 minutes. The solid product was collected by centrifugation and vacuum dried at 60°C. The obtained d-PtNi / MAPbI3 photocatalyst was recorded as 1 wt% d-PtNi / MAPbI3.

[0039] Example 3

[0040] Place 40 mL of hydroiodic acid (48% aqueous solution) and 10 mL of hypophosphorous acid (50% aqueous solution) in a 100 mL beaker, add 14 g of lead iodide and continue stirring. After it is completely dissolved, slowly add 4.825 g of methylamine iodide. After stirring for 2 hours, centrifuge to separate the black powder and solution. The obtained MAPbI3 saturated solution is retained, and the black powder is MAPbI3, which is vacuum dried at 60°C for later use.

[0041] 0.12 mmol of platinum acetylacetonate, 0.12 mmol of nickel acetylacetonate, 4 mmol of NaBH4, and 4 g of PVP were added to a reactor containing 20 mL of ethylenediamine and stirred until dissolved. The mixture was solvothermally reacted at 160°C for 20 h and centrifuged to dry to obtain PtNi alloy powder. The PtNi alloy powder was placed in 2 mL of HI acid and dealloyed for 2 h before centrifugation to obtain d-PtNi.

[0042] 250 mg of MAPbI3 was dispersed in a saturated MAPbI3 solution, 12.5 mg of d-PtNi was added, and the mixture was irradiated under simulated sunlight with a 300 W xenon lamp as the light source for 30 minutes. The solid product was collected by centrifugation and vacuum dried at 60°C. The obtained d-PtNi / MAPbI3 photocatalyst was recorded as 5 wt% d-PtNi / MAPbI3.

[0043] Comparative Example 1

[0044] Place 40 mL of hydroiodic acid (48% aqueous solution) and 10 mL of hypophosphorous acid (50% aqueous solution) in a 100 mL beaker, add 14 g of lead iodide and continue stirring. After it is completely dissolved, slowly add 4.825 g of methylamine iodide. After stirring for 2 hours, centrifuge to separate the black powder and solution. The obtained MAPbI3 saturated solution is retained, and the black powder is MAPbI3, which is vacuum dried at 60°C for later use.

[0045] 0.12 mmol of platinum acetylacetonate, 4 mmol of NaBH4, and 4 g of PVP were added to a reactor containing 20 mL of ethylenediamine and stirred until dissolved. The mixture was subjected to solvent thermal reaction at 160°C for 20 h and centrifuged to obtain Pt powder.

[0046] 250 mg of MAPbI3 was dispersed in a saturated MAPbI3 solution, 7.5 mg of Pt powder was added, and the mixture was irradiated under simulated sunlight with a 300 W xenon lamp as the light source for 30 minutes. The solid product was collected by centrifugation and vacuum dried at 60°C. The obtained photocatalyst was recorded as 3 wt% Pt / MAPbI3.

[0047] Comparative Example 2

[0048] Place 40 mL of hydroiodic acid (48% aqueous solution) and 10 mL of hypophosphorous acid (50% aqueous solution) in a 100 mL beaker, add 14 g of lead iodide and continue stirring. After it is completely dissolved, slowly add 4.825 g of methylamine iodide. After stirring for 2 hours, centrifuge to separate the black powder and solution. The obtained MAPbI3 saturated solution is retained, and the black powder is MAPbI3, which is vacuum dried at 60°C for later use.

[0049] 0.12 mmol of platinum acetylacetonate, 0.12 mmol of nickel acetylacetonate, 4 mmol of NaBH4, and 4 g of PVP were added to a reactor containing 20 mL of ethylenediamine and stirred until dissolved. The mixture was subjected to solvent thermal reaction at 160°C for 20 h and centrifuged to obtain PtNi alloy powder.

[0050] 250 mg of MAPbI3 was dispersed in a saturated MAPbI3 solution, 7.5 mg of PtNi alloy powder was added, and the mixture was irradiated under simulated sunlight with a 300 W xenon lamp as the light source for 30 minutes. The solid product was collected by centrifugation and vacuum dried at 60°C. The obtained photocatalyst was recorded as 3 wt% PtNi / MAPbI3.

[0051] The photocatalysts and co-catalysts obtained in the examples and comparative examples were characterized by XRD, UV-visible diffuse reflectance and transmission electron microscopy. Figure 1 As shown in a, the PtNi alloy has good crystallinity. The d-PtNi formed by dealloying has no change in the characteristic peak position compared with the PtNi alloy, but the degree of crystallinity is reduced. Figure 1As shown in Figure b, MAPbI3 has a well-crystalline tetragonal phase structure. After loading PtNi alloy and d-PtNi, no corresponding crystallization peak was found, and the crystal structure of MAPbI3 was not changed.

[0052] like Figure 2 As shown in Figure 2, d-PtNi exhibits an agglomerated particle structure. Figure 3 As shown, in 3wt% d-PtNi / MAPbI3, d-PtNi is dispersed on the surface of MAPbI3, d-PtNi exposes the (111) crystal plane, and MAPbI3 exposes the (202) crystal plane.

[0053] Example 4

[0054] 250 mg of 1wt% d-PtNi / MAPbI3, 3wt% d-PtNi / MAPbI3, 5wt% d-PtNi / MAPbI3, MAPbI3, 3wt% PtNi / MAPbI3, and 3wt% Pt / MAPbI3 were respectively dispersed in 50 mL of perovskite saturated HI solution, and the reaction solution was transferred to a photocatalytic reactor (volume: about 100 mL). The reactor was connected to a gas collection system and a gas chromatography gas evaluation system at the top, and circulating cooling water (25°C) at the bottom to ensure a constant temperature during the reaction. A 300W xenon lamp was used as the light source to simulate sunlight (AM1.5G).

[0055] like Figure 4 As shown in a, the performance of the photocatalysts at different d-PtNi loadings first increases and then decreases with the loading. 3wt% d-PtNi / MAPbI3 has the highest hydrogen production rate, which can reach 5644μmol / h. The corresponding solar energy to hydrogen energy conversion efficiency (i.e., photoinduced hydroiodic acid decomposition efficiency) reaches 6.15%. Figure 4 As shown in Figure b, the hydrogen production performance of 3wt% d-PtNi / MAPbI3 is better than that of 3wt% PtNi / MAPbI3 and 3wt% Pt / MAPbI3 with the same promoter loading, which improves the performance of the composite photocatalyst while reducing the amount of Pt used. Figure 5 As shown, there was no performance degradation of 3wt% d-PtNi / MAPbI3 during 8 cycles.

[0056] like Figure 6 As shown, compared with 3wt% PtNi / MAPbI3 and MAPbI3, the photocurrent of 3wt% d-PtNi / MAPbI3 is significantly increased and the impedance is significantly reduced, indicating that 3wt% PtNi / MAPbI3 has a better ability to separate photogenerated carriers, giving it better photocatalytic performance.

[0057] Example 5

[0058] Place 40 mL of hydroiodic acid (48% aqueous solution) and 10 mL of hypophosphorous acid (50% aqueous solution) in a 100 mL beaker, add 14 g of lead iodide and continue stirring. After it is completely dissolved, slowly add 4.825 g of methylamine iodide. After stirring for 1 hour, centrifuge to separate the black powder and solution. The obtained MAPbI3 saturated solution is retained, and the black powder is MAPbI3, which is vacuum dried at 60°C for later use.

[0059] 0.12 mmol of platinum acetylacetonate, 0.12 mmol of nickel acetylacetonate, 4 mmol of NaBH4, and 4 g of PVP were added to a reactor containing 20 mL of ethylenediamine and stirred until dissolved. Solvothermal reaction was carried out at 150°C for 24 hours, and centrifugation was performed to obtain PtNi alloy powder. The PtNi alloy powder was placed in 2 mL of HI acid, dealloyed for 1 hour, and then centrifuged to obtain d-PtNi.

[0060] 250 mg of MAPbI3 was dispersed in a saturated MAPbI3 solution, 7.5 mg of d-PtNi was added, and the mixture was irradiated under simulated sunlight with a 300 W xenon lamp as the light source for 20 minutes. The solid product was collected by centrifugation and vacuum dried at 60°C to obtain a d-PtNi / MAPbI3 photocatalyst.

[0061] Example 6

[0062] Place 40 mL of hydroiodic acid (48% aqueous solution) and 10 mL of hypophosphorous acid (50% aqueous solution) in a 100 mL beaker, add 14 g of lead iodide and continue stirring. After it is completely dissolved, slowly add 4.825 g of methylamine iodide. After stirring for 3 hours, centrifuge to separate the black powder and solution. The obtained MAPbI3 saturated solution is retained, and the black powder is MAPbI3, which is vacuum dried at 60°C for later use.

[0063] 0.12 mmol of platinum acetylacetonate, 0.12 mmol of nickel acetylacetonate, 4 mmol of NaBH4, and 4 g of PVP were added to a reactor containing 20 mL of ethylenediamine and stirred until dissolved. The mixture was solvothermally reacted at 170°C for 18 hours and centrifuged to obtain PtNi alloy powder. The PtNi alloy powder was placed in 2 mL of HI acid and dealloyed for 3 hours before centrifugation to obtain d-PtNi.

[0064] 250 mg of MAPbI3 was dispersed in a saturated MAPbI3 solution, 7.5 mg of d-PtNi was added, and the mixture was irradiated under simulated sunlight with a 300 W xenon lamp as the light source for 40 minutes. The solid product was collected by centrifugation and vacuum dried at 60°C to obtain a d-PtNi / MAPbI3 photocatalyst.

[0065] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for preparing a d-PtNi / MAPbI3 photocatalyst, characterized in that: The following steps are involved: S1, mixing platinum source, nickel source, NaBH4, PVP and ethylenediamine uniformly and performing a solvothermal reaction to obtain a PtNi alloy, and adding the PtNi alloy to hydroiodic acid for a dealloying reaction to obtain d-PtNi; S2. Add d-PtNi and MAPbI3 into a saturated MAPbI3 solution, stir, and then perform a photodeposition reaction to obtain a d-PtNi / MAPbI3 photocatalyst.

2. The preparation method according to claim 1, wherein In step S1, the platinum source includes platinum acetylacetonate, the nickel source includes nickel acetylacetonate, and the ratio of the platinum source, the nickel source, NaBH4 and PVP is (3 mmol): (3 mmol): (95-105 mmol): (95-105 g).

3. The preparation method according to claim 1, wherein In step S1, the solvent thermal reaction is carried out at 150-170° C. for 18-24 hours, and the dealloying reaction time is 1-3 hours.

4. The preparation method according to claim 1, wherein In step S2, the mass of d-PtNi is 1% to 5% of the mass of MAPbI3.

5. The preparation method according to claim 1, wherein In step S2, the photodeposition reaction time is 20 to 40 minutes.

6. The preparation method according to claim 1, wherein Also included are methods for preparing MAPbI3 and MAPbI3 saturated solutions: Lead iodide is dissolved in a mixed solution of hydroiodic acid and hypophosphorous acid. After the lead iodide is completely dissolved, methylamine iodide is added. After stirring for reaction, solid-liquid separation is performed to obtain MAPbI3 and a saturated solution of MAPbI3.

7. The preparation method according to claim 6, wherein The volume ratio of hydroiodic acid to hypophosphorous acid is (3.5-4.5):1, and the molar ratio of lead iodide to methylamine iodide is 1:(0.99-1.01).

8. The preparation method according to claim 6, wherein The stirring reaction time is 1 to 3 hours.

9. A d-PtNi / MAPbI3 photocatalyst, characterized in that The method is obtained by the preparation method according to any one of claims 1 to 8.

10. Use of the d-PtNi / MAPbI3 photocatalyst according to claim 9 in photocatalytic cracking of HI to produce hydrogen.

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