A Ru single-atom and Ru nanoparticle co-supported crystalline red phosphorus photocatalyst for visible light water splitting to produce hydrogen.

Abstract

A Ru single-atom and Ru nanoparticle synergistic supported crystalline red phosphorus photocatalyst for visible light water splitting to produce hydrogen is presented, relating to the field of photocatalytic materials. Firstly, Ru single atoms are precisely anchored to intrinsic phosphorus vacancies (V0.05) in CRP via an impregnation-calcination method. P Defect sites were identified, and then a hydrothermal method was used to grow uniformly dispersed Ru nanoparticles in situ at the pre-anchored Ru single-atom sites. 1‑NP / CRP. Pre-anchoring of Ru single atoms has the following advantages: 1. Effectively repairs V P 1. It eliminates defects, suppresses the charge depth trapping effect, and improves the efficiency of photocatalytic reaction; 2. It provides growth sites for Ru nanoparticles, ensuring the uniform dispersion and stable adhesion of Ru nanoparticles on the CRP surface; 3. As a bridge for charge transfer, it greatly promotes the separation and transfer of charge between CRP and Ru nanoparticles during photocatalysis, enhancing catalytic performance. Results show that Ru… 1‑NP / CRP photocatalytic hydrogen production performance reaches up to 3175 μmol g ‑1 h ‑1 .

Description

Technical Field

[0001] This invention relates to the field of photocatalytic materials, specifically to a highly efficient photocatalyst for hydrogen production via water splitting using ruthenium (Ru) single-atom and Ru nanoparticle synergistic support of crystalline red phosphorus (CRP) elemental photocatalyst (Ru). 1-NP Preparation and application of CRP. Background Technology

[0002] Hydrogen (H2) is the most basic molecule, releasing a large amount of energy during oxidation, making it an ideal green energy source to replace traditional fossil fuels. Photocatalytic water splitting (PHE) is an ideal pathway for hydrogen production, aligning with the national "dual-carbon" policy development strategy. The key to this technology lies in the design and development of highly efficient photocatalysts.

[0003] CRP has attracted much attention in the field of photocatalysis due to its tunable bandgap structure, full visible spectrum response, non-toxic stability, low cost, and wide availability. However, the large number of intrinsic P vacancies (V vacancies) in the CRP chemical structure... P The defects lead to a deep charge trapping effect, which severely limits its activity and stability in the photocatalytic water splitting process for hydrogen production. Furthermore, the scarcity of active sites on the CRP surface further restricts its photocatalytic performance.

[0004] To overcome these challenges, this invention proposes an innovative Ru single-atom pre-anchoring strategy, aiming to: 1. fill the V atom on the CRP surface P Defects, eliminate V P 1. The adverse effects of defects; 2. As growth sites, it induces the in-situ construction of highly dispersed and stable Ru nanoparticles. This strategy enables effective control over CRP defects, electronic and energy level structures, thereby significantly improving the photocatalytic water splitting hydrogen production performance of CRP and providing new ideas for the structural design of high-performance photocatalytic materials. Summary of the Invention

[0005] This invention proposes a novel strategy for pre-anchoring V in CRP using Ru metal single atoms. P Defects were identified, and highly dispersed Ru nanoparticles were grown in situ at these pre-anchored sites, thus successfully preparing Ru... 1-NP / CRP photocatalyst. This preparation strategy is not only cost-effective but also simple. By precisely controlling the actual metal loading, the photocatalytic performance was effectively optimized. This novel catalyst exhibits outstanding activity in photocatalytic water splitting for hydrogen production, setting a new record for the highest activity of visible light photocatalytic water splitting for hydrogen production from elemental semiconductors. This breakthrough provides a new direction for research and application in the field of photocatalysis.

[0006] A Ru single-atom and Ru nanoparticle synergistic supported crystalline red phosphorus photocatalyst for visible light water splitting to produce hydrogen. 1-NP The method for preparing / CRP is characterized by comprising the following steps:

[0007] S1. Commercial red phosphorus was purified by hydrothermal method to remove surface oxides and obtain amorphous red phosphorus ARP;

[0008] S2. ARP and an appropriate amount of iodine are vacuum-sealed in a quartz tube and calcined at high temperature in a muffle furnace.

[0009] S3. The obtained product is washed with deionized water and ethanol to remove residual byproducts, and then dried and ground to obtain CRP sample;

[0010] S4. Prepare a ruthenium trichloride (RuCl3) solution of a certain concentration, disperse the above CRP sample in deionized water, and then add RuCl3 solution to it and soak at room temperature.

[0011] S5. The impregnated sample is evaporated using a rotary evaporator and then collected, and calcined in an Ar atmosphere to obtain Ru single-atom supported CRP, i.e., Ru1 / CRP;

[0012] S6. Disperse Ru1 / CRP in water, then add an appropriate amount of RuCl3 solution and stir until homogeneous;

[0013] S7. Transfer the above solution to an autoclave for hydrothermal treatment, then cool to room temperature, wash the product with deionized water / ethanol, centrifuge, and dry to obtain Ru. 1-NP / CRP sample.

[0014] The hydrothermal purification conditions in S1 were: 200℃ for 12 hours.

[0015] The high-temperature calcination temperature in S2 is set as follows: heating from room temperature to 550℃ at a heating rate of 2℃ / min and holding at this temperature for 4 hours; then cooling to 280℃ at a cooling rate of 1℃ / min and holding at this temperature for 4 hours; finally cooling to room temperature at a cooling rate of 0.2℃ / min; preferably, the mass ratio of ARP to iodine is (15-25):1, preferably 20:1.

[0016] The mass ratio of Ru:P in S4 is 1.0-2.0wt%, preferably 1.5wt%, and the impregnation time is 6h.

[0017] In S5, the rotary evaporation temperature is 40-70℃, the Ar atmosphere calcination temperature is set to 180-250℃ (preferably 200℃), and the calcination time is 0.5-1.5h (preferably 1h).

[0018] The mass ratio of Ru to P in S6 is 0.5-2 wt%, preferably 1.5 wt%.

[0019] The hydrothermal treatment in S7 is as follows: reaction temperature 180–220℃, preferably 200℃; treatment time 8–16h, preferably 12h.

[0020] Ru prepared by this invention 1-NP / CRP photocatalyst is used for photocatalytic water splitting to produce hydrogen. The specific steps are as follows: The photocatalyst is dispersed in a mixture of deionized water and methanol, and the water splitting to produce hydrogen is catalyzed under the irradiation of a xenon lamp (Microsolar300) or visible light.

[0021] The beneficial effects of this invention are:

[0022] 1. This invention proposes an innovative preparation method, which involves CRP at V... P Pre-anchoring Ru single atoms at the defect site enables multiple functions. First, the introduction of Ru single atoms effectively repairs V... P The pre-anchoring process significantly reduces the depth trapping effect, thereby improving the efficiency of the photocatalytic reaction. Secondly, this pre-anchoring process provides ideal growth sites for the in-situ growth of Ru nanoparticles, ensuring their uniform dispersion and stable attachment. More importantly, the Ru single atom acts as a bridge for charge transfer, greatly promoting charge separation and transfer during the photocatalytic process, further enhancing photocatalytic performance. Combining these advantages, the preparation method of this invention significantly improves the photocatalytic water splitting hydrogen production performance and stability of CRP.

[0023] 2. This invention successfully pre-anchors Ru single atoms to V using an impregnation-calcination method. P To address the defects, a hydrothermal method was then used to introduce uniformly dispersed Ru nanoparticles in situ at Ru single-atom sites. This preparation process is simpler and more convenient compared to other photocatalyst preparation methods.

[0024] 3. The Ru prepared by this invention 1-NP / CRP photocatalytic materials exhibited excellent hydrogen production activity, with an activity as high as 3175 μmol g. -1 h -1 This value is 454 times that of the original CRP, and it also breaks the current record for the highest photocatalytic hydrogen production activity of elemental semiconductors under visible light. Attached Figure Description

[0025] Figure 1 Ru prepared for this invention 1-NP(a) SEM, (b) TEM, (c) Aberration-corrected HAADF-STEM, (d) STEM and corresponding (e, f) EDS elemental distribution maps of the CRP (1.27wt% Ru) sample, showing the successful introduction of Ru single atoms and Ru nanoparticles on the CRP surface;

[0026] Figure 2 CRP, Ru1 / CRP and Ru prepared for this invention 1-NP The EPR spectra of the CRP samples demonstrate that the introduction of Ru species (Ru single atoms and Ru nanoparticles) effectively eliminated the Va on the CRP surface. P defect;

[0027] Figure 3 CRP, Ru1 / CRP and Ru prepared for this invention 1-NP The XRD pattern of the CRP sample shows that the introduction of Ru metal did not change the bulk crystal structure of CRP.

[0028] Figure 4 This invention demonstrates the CRP, Ru1 / CRP, and Ru prepared according to the present invention. 1-NP A comparison of the photocatalytic water splitting activity of CRP samples under visible light. The figure clearly shows that the introduction of Ru metal significantly enhances the photocatalytic water splitting activity of CRP. Specifically, the Ru content is 1.27 wt%. 1-NP The / CRP sample exhibited the highest photocatalytic hydrogen production activity, reaching 3175 μmol g. -1 h -1 The ratios were 454 times and 15 times that of CRP and Ru1 / CRP, respectively. This result fully demonstrates the enormous potential and application value of the photocatalytic material prepared in this invention in improving photocatalytic performance;

[0029] Figure 5 Ru prepared for this invention 1-NP Photocatalytic hydrogen production stability test diagram of / CRP (1.27wt%Ru) sample. After a 24-hour photocatalytic hydrogen production activity test (test environment was vacuum to eliminate air interference; 4 hours per cycle, 6 cycles in total; the initial process of each cycle was simply to evacuate the system without changing the reaction solution; after 4 cycles, the catalyst was centrifuged and dried, stored for 2 weeks, and then the cycle process was repeated 2 times), the hydrogen production activity of the sample did not show significant decay, proving that the material has good stability. Detailed Implementation

[0030] The technical solution of the present invention will be further described in detail below through specific embodiments. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present disclosure.

[0031] Example 1:

[0032] First, 500 mg of commercial red phosphorus was dispersed in 30 mL of deionized water and stirred until fully dispersed. Then, this mixture was transferred to a polytetrafluoroethylene-lined high-pressure reactor and hydrothermally purified at 200 °C for 12 hours. After purification, the sample was washed repeatedly with deionized water and ethanol and dried to remove impurities and excess water, yielding ARP. Next, 200 mg of ARP and 10 mg of iodine were placed in a vacuum-sealed quartz tube. The quartz tube was then placed in a heating device and heated from room temperature to 550 °C at a rate of 2 °C / min, held at this temperature for 4 hours, and then slowly cooled to 280 °C at a rate of 1 °C / min, held for 4 hours, and then slowly cooled to room temperature at a rate of 0.2 °C / min. The sample was then thoroughly washed with deionized water and ethanol to remove any possible residual byproducts. Finally, the product was dried and ground to obtain CRP.

[0033] 100 mg CRP was dispersed in 50 mL of deionized water and stirred until uniformly dispersed. Then, 0.62 mL of RuCl3 solution (0.024 mol / L) was slowly added and stirred for 6 hours. Next, the mixture was thoroughly dried using a rotary evaporator (60 °C). Finally, the dried sample was placed in a tube furnace and calcined at 200 °C under an argon atmosphere for 1 hour to obtain Ru1 / CRP.

[0034] 100 mg of the prepared Ru1 / CRP material was dissolved in 50 mL of water; subsequently, different volumes (0.21 mL, 0.41 mL, 0.62 mL, and 0.83 mL) of RuCl3 solution were added to the solution (0.62 mL corresponds to the product Ru). 1-NP The Ru:P ratio in the CRP was 1.27 wt%, and the mixture was ultrasonically stirred. Then, the resulting mixture was transferred to a high-pressure reactor and reacted at 200°C for 8-16 hours. Finally, the sample was washed, centrifuged, and dried multiple times to obtain Ru. 1-NP / CRP material.

[0035] Prepare Ru 1-NPThe CRP photocatalyst is applied to the visible light water splitting hydrogen production reaction. The specific operation procedure is as follows: First, 20 mg of photocatalyst is uniformly dispersed in a mixture of 45 mL of deionized water and 5 mL of methanol. Then, this suspension is placed under a 300 W xenon lamp (Microsolar300) equipped with a 420 nm cutoff filter to carry out the photocatalytic reaction. The amount of hydrogen produced is measured by a GC910 gas chromatograph with Ar as the carrier gas, thereby quantitatively evaluating the hydrogen production performance of the photocatalyst.

[0036] The single-atom pre-anchoring strategy provided by this invention plays a key role in regulating the defects, electronic and energy level structure of CRP, significantly improving the performance and stability of photocatalytic water splitting for hydrogen production, and opening up new avenues for research and application in related fields.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a Ru single-atom and Ru nanoparticle synergistic supported crystalline red phosphorus photocatalyst for visible light water splitting to produce hydrogen, characterized in that, The preparation method includes the following steps: S1. Commercial red phosphorus was purified by hydrothermal method to remove surface oxides and obtain amorphous red phosphorus ARP; S2. ARP and an appropriate amount of iodine are vacuum-sealed in a quartz tube and calcined at high temperature in a muffle furnace. S3. The obtained product was washed with deionized water and ethanol to remove residual byproducts, and then dried and ground to obtain crystalline red phosphorus CRP sample. S4. Prepare a ruthenium trichloride (RuCl3) solution of a certain concentration, disperse the above CRP sample in deionized water, then add RuCl3 solution to it, and soak at room temperature; S5. The impregnated sample is evaporated using a rotary evaporator and then collected, and calcined in an Ar atmosphere to obtain Ru single-atom supported CRP, i.e., Ru1 / CRP; S6. Disperse Ru1 / CRP in water, then add an appropriate amount of RuCl3 solution and stir until homogeneous; S7. Transfer the above solution to an autoclave for hydrothermal treatment, then cool to room temperature, wash the product with deionized water / ethanol, centrifuge, and dry to obtain Ru. 1-NP / CRP sample.

2. The method according to claim 1, characterized in that, The hydrothermal purification conditions for S1 were: 200 °C for 12 h.

3. The method according to claim 1, characterized in that, The high-temperature calcination temperature of S2 is set as follows: heat from room temperature to 550 ℃ at a heating rate of 2 ℃ / min and hold at this temperature for 4 h; then cool to 280 ℃ at a cooling rate of 1 ℃ / min and hold for 4 h; finally cool to room temperature at a cooling rate of 0.2 ℃ / min; the mass ratio of ARP to iodine is (15-25):

1.

4. The method according to claim 3, characterized in that, The mass ratio of ARP to iodine is 20:

1.

5. The method according to claim 1, characterized in that, In S4, the Ru:P mass ratio is 1.0-2.0wt%, and the impregnation time is 6 h.

6. The method according to claim 5, characterized in that, The mass ratio of Ru to P in S4 is 1.5 wt%.

7. The method according to claim 1, characterized in that, The rotary evaporation temperature in S5 is 40-70 ℃, the calcination temperature in Ar atmosphere is set to 180-250 ℃, and the calcination time is 0.5-1.5 h.

8. The method according to claim 7, characterized in that, The calcination temperature in the Ar atmosphere was set to 200 ℃, and the calcination time was 1 h.

9. The method according to claim 1, characterized in that, The newly added Ru to P mass ratio in S6 is 0.5 - 2 wt%.

10. The method according to claim 9, characterized in that, The newly added Ru to P in S6 has a mass ratio of 1.5 wt%.

11. The method according to claim 1, characterized in that, The hydrothermal treatment in S7 is as follows: reaction temperature 180 – 220℃; treatment time 8 – 16 h.

12. The method according to claim 11, characterized in that, The hydrothermal treatment in S7 is as follows: reaction temperature 200 ℃; treatment time 12 h.

13. Ru prepared according to any one of claims 1-12 1-NP / CRP photocatalyst.

14. Ru prepared according to any one of claims 1-12 1-NP Application of CRP photocatalyst in photocatalytic water splitting for hydrogen production.

15. The application according to claim 14, characterized in that, The specific steps are as follows: The photocatalyst is dispersed in a mixture of deionized water and methanol, and hydrogen is produced by catalytic water splitting under xenon lamp or visible light irradiation.

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