A CoP / NiCoP electrocatalyst prepared based on phosphine gas-phase phosphorization and a preparation method and application thereof

Abstract

The application discloses a CoP / NiCoP electrocatalyst prepared based on phosphine gas-phase phosphorization, and a preparation method and application thereof, and relates to the technical field of electrocatalytic material preparation. The preparation method comprises the following steps: adding a nickel source and a cobalt source into isopropyl alcohol, and after adding glycerol, performing a solvothermal reaction, a hydrothermal treatment and a nitrogen atmosphere heat treatment to obtain a Co / NiCo precursor; screening the precursor and placing the same in a tube furnace to perform gas-phase phosphorization treatment under a phosphine atmosphere to obtain the CoP / NiCoP electrocatalyst. The application uses a low-concentration phosphine gas which can be measured as a phosphorus source, which is beneficial to reducing the influence of uneven phosphorus release or local over-phosphorization of a solid phosphorus source, the obtained CoP / NiCoP electrocatalyst has a high phosphine adsorption conversion capacity and good alkaline water decomposition hydrogen / oxygen evolution activity, and can be used in the fields of phosphine resource conversion and electrocatalytic water decomposition.

Description

Technical Field

[0001] This invention relates to the field of electrocatalytic material preparation technology, and more specifically, to a CoP / NiCoP electrocatalyst prepared based on hydrogen phosphide gas-phase phosphating, its preparation method, and its application. Background Technology

[0002] Hydrogen energy, with its advantages of high energy density, clean combustion products, and wide availability, is considered an important energy carrier for achieving low-carbon energy conversion and storage. Electrocatalytic water splitting for hydrogen production converts renewable electrical energy into chemical energy, making it an environmentally friendly and promising method. The electrocatalytic water splitting process typically involves a cathode hydrogen evolution reaction and an anode oxygen evolution reaction; the reaction kinetics of both affect the overall water splitting efficiency. Therefore, efficient, stable, and low-cost bifunctional electrocatalysts are needed to lower the reaction energy barrier.

[0003] Currently, platinum and platinum-based precious metal materials are still considered to be high-performance catalysts for hydrogen evolution reaction. However, the scarcity and high price of precious metal resources limit their widespread application in large-scale water electrolysis for hydrogen production. Therefore, developing non-precious metal electrocatalysts with lower costs, abundant reserves, and stable performance is an important research direction in the field of electrocatalytic water splitting for hydrogen production.

[0004] Transition metal phosphides have attracted widespread attention in the field of hydrogen evolution reaction catalysts due to their good conductivity, abundant active sites, and relatively low preparation cost. Among them, cobalt-based phosphides and nickel-cobalt-based phosphides have shown good electrocatalytic activity and stability, and have the potential to replace noble metal catalysts. In particular, by controlling the metal composition, precursor structure, and phosphating conditions, the electronic structure of the materials can be further improved, more active sites can be exposed, and the electrocatalytic hydrogen evolution performance can be enhanced.

[0005] In existing technologies, CoP, NiCoP, and CoP / NiCoP composite phosphides typically involve first preparing metal hydroxide, oxide, metal-organic framework, or metal salt precursors, followed by phosphating using methods such as sodium hypophosphite thermal decomposition, red / white phosphorus solid-phase phosphating, or phosphorus-containing organic liquid-phase phosphating. While these routes can yield cobalt-based and nickel-cobalt-based phosphides, the contact and phosphorus release process between the solid or liquid phosphorus source and the precursor are difficult to measure in real time. This can easily lead to problems such as excessively high local phosphorus source concentration, surface phosphating followed by insufficient internal conversion, random interface formation, excessively high phosphating temperatures, and sintering or collapse of micro / nano structures. Consequently, these issues affect the catalyst's compositional uniformity, interface stability, and electrocatalytic performance.

[0006] Compared to the aforementioned solid or liquid phosphorus sources, phosphine gas can continuously enter the precursor channels and surface in a gaseous manner, and its concentration, flow rate, temperature, and time can be metered and controlled. Combining the Co / NiCo precursor with a low-concentration phosphine gas-phase phosphating process can form CoP / NiCoP phosphide materials at lower temperatures, while simultaneously converting phosphine into solid-phase metal phosphides, thus achieving a balance between phosphorus source utilization, micro / nano structure preservation, and improved electrocatalytic performance.

[0007] Therefore, there is an urgent need to provide a method for preparing CoP / NiCoP electrocatalysts with controllable gas-phase phosphine phosphine as the core, in order to solve the problems of complex phosphine phosphine process, difficulty in controlling phosphorus release process, insufficient preservation of micro-nano structure, and the need to improve the comprehensive performance of hydrogen evolution / oxygen evolution in the preparation of existing metal phosphide catalysts. Summary of the Invention

[0008] To address the problems of complex preparation processes, difficult control of phosphating conditions, low utilization of some phosphorus sources, and the need for further improvement in catalytic performance of existing metal phosphide electrocatalysts, this invention provides a CoP / NiCoP electrocatalyst and its preparation method.

[0009] This invention involves first preparing a Co / NiCo composite precursor containing Co and NiCo phases, and then using low-concentration phosphine gas as a meterable gaseous phosphorus source for in-situ phosphating, thereby converting the Co / NiCo precursor into a CoP / NiCoP electrocatalyst at a relatively low temperature. This method effectively controls the phosphating temperature, phosphine concentration, gas flow rate, and phosphating time, and enhances the phosphine adsorption and conversion capacity and alkaline water splitting electrocatalytic activity of the resulting material through its porous micro / nano structure.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] A method for preparing CoP / NiCoP electrocatalysts based on gas-phase phosphine phosphide treatment includes the following steps: S1: Add nickel source and cobalt source to isopropanol and stir to form a mixed solution. Then add glycerol to the mixed solution and continue stirring until the solution is transparent and uniform to obtain a transparent solution. S2: The transparent solution obtained in step S1 is transferred to an autoclave for a solvothermal reaction. After the reaction is completed, the product is washed and dried to obtain a primary powder product. S3: Add the primary powder product obtained in step S2 to deionized water for hydrothermal treatment. After the hydrothermal treatment is completed, wash and dry the product. S4: The product obtained in step S3 is placed in a tube furnace and heat-treated under a nitrogen atmosphere to obtain the Co / NiCo precursor. S5: The Co / NiCo precursor obtained in step S4 is sieved to obtain precursor powder; S6: Place the precursor powder obtained in step S5 in a tube furnace and perform gas-phase phosphating treatment under a phosphine atmosphere. After phosphating, cool to room temperature to obtain the CoP / NiCoP electrocatalyst.

[0012] Furthermore, in step S1, the nickel source is Ni(NO3)2·6H2O, and the cobalt source is Co(NO3)2·6H2O; The molar ratio of Ni(NO3)2·6H2O to Co(NO3)2·6H2O is 1:(1-4), preferably 1:2; the volume ratio of isopropanol to glycerol is (3-8):1, preferably 5:1.

[0013] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: by adjusting the ratio of nickel source to cobalt source and the ratio of isopropanol to glycerol, it is beneficial to control the relative content of Ni and Co components in the precursor and the solvothermal reaction process, thereby obtaining a Co / NiCo precursor with a more uniform composition that is suitable for subsequent hydrothermal treatment and gas phase phosphating.

[0014] Furthermore, in step S1, the mass-to-volume ratio of the nickel source and isopropanol is 1.8 mg / mL.

[0015] Furthermore, in step S2, the temperature of the solvothermal reaction is 140 ℃~180 ℃, the reaction time is 4 h~8 h, the preferred temperature is 160 ℃, and the preferred time is 6 h; The washing is performed by centrifugal washing with alcohol, and the drying is performed by vacuum drying at a temperature of 60.0 ℃ for 12.0 h.

[0016] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: within the range of solvothermal temperature and reaction time, it is beneficial for nickel and cobalt sources to fully participate in the precursor formation process; after the reaction, unreacted substances and soluble residues can be removed by centrifugal washing, and subsequent drying can obtain a primary powder product that is easy to undergo subsequent hydrothermal treatment.

[0017] Furthermore, in step S3, the hydrothermal treatment temperature is 130 ℃~170 ℃, the hydrothermal treatment time is 3 h~8 h, the preferred temperature is 150 ℃, and the preferred time is 5 h; The washing is performed by centrifugal washing with alcohol, and the drying is performed by vacuum drying at a temperature of 60.0 ℃ for 12.0 h.

[0018] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: further hydrothermal treatment is beneficial to the control of the micro-nano structure of the primary powder product; centrifugal washing and drying after hydrothermal treatment can reduce the influence of soluble impurities and residual solvents on the subsequent heat treatment process.

[0019] Furthermore, in step S4, the heat treatment temperature is 250 ℃~350 ℃, preferably 300 ℃, and the heat treatment time is 2h.

[0020] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: Furthermore, in step S5, the particle size of the precursor powder is 40-60 mesh.

[0021] The beneficial effects of adopting the above-mentioned further technical solution are: heat treatment under a nitrogen atmosphere can reduce the oxidation of the precursor during the heating process and improve the structural stability of the precursor, thereby providing a stable precursor material for subsequent phosphine gas-phase phosphating.

[0022] Furthermore, the concentration of the phosphine gas is 1000 ppm to 1050 ppm, and the flow rate of the phosphine gas is 100 mL / min; The temperature of the gas phase phosphating treatment is 280 ℃~320 ℃, preferably 320 ℃, and the phosphating time is 120 min~200 min.

[0023] The beneficial effects of adopting the above-mentioned further technical solution are as follows: using a low-concentration phosphine mixture of 1000 ppm to 1050 ppm as a measurable gaseous phosphorus source, and controlling the total flow rate of the mixture, phosphating temperature, and phosphating time, it is beneficial to regulate the mass transfer and phosphating reaction degree of phosphine on the surface and in the pores of the precursor, thereby improving the controllability of the gas-phase phosphating process. Experimental results show that, within the investigated range of 280 ℃ to 320 ℃, the sample prepared at 320 ℃ has a higher phosphine adsorption and conversion capacity.

[0024] Furthermore, in step S6, the amount of the precursor powder used is 30 mg to 80 mg, preferably 50 mg.

[0025] Furthermore, in step S6, before introducing phosphine gas, the tubular furnace is purged with nitrogen; the phosphine gas is a low-concentration phosphine mixture diluted with nitrogen; after phosphating is completed, the introduction of phosphine gas is stopped, and the furnace is switched to a nitrogen protective atmosphere to cool to room temperature; the phosphating tail gas is discharged after absorption or purification treatment.

[0026] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: nitrogen replacement before phosphating can reduce the influence of components such as oxygen in the system on the gas phase phosphating process; the use of nitrogen-diluted low-concentration phosphine mixed gas is beneficial for regulating the phosphorus source supply; cooling under a nitrogen protective atmosphere after phosphating can reduce the possibility of oxidation of the obtained phosphide at high temperature, and the absorption or purification of phosphating tail gas is beneficial for improving the safety of process operation.

[0027] The present invention also provides a CoP / NiCoP electrocatalyst prepared by the method described above, wherein the CoP / NiCoP electrocatalyst has a porous micro / nano structure and a surface exhibiting a wrinkled, lamellar, or flower-like morphology.

[0028] The present invention also provides the application of the CoP / NiCoP electrocatalyst in an alkaline electrocatalytic water evolution hydrogen electrode, oxygen evolution electrode, or overall water splitting device, wherein the CoP / NiCoP electrocatalyst is used for electrocatalytic hydrogen evolution reaction, oxygen evolution reaction, and / or overall water splitting reaction under alkaline conditions.

[0029] Compared with the prior art, the present invention has the following beneficial effects: First, the preparation process of this invention is simple and the conditions are controllable. This invention uses a Co / NiCo precursor and phosphine gas for a gas-phase phosphating reaction. By controlling the phosphating temperature, phosphine concentration, gas flow rate, and phosphating time, the conversion of the Co / NiCo precursor into a CoP / NiCoP electrocatalyst can be achieved. Compared with traditional phosphating methods that use sodium hypophosphite, red phosphorus, white phosphorus, or phosphorus-containing organic matter as phosphorus sources, this invention directly introduces a low concentration of 1000 ppm to 1050 ppm phosphine gas. The concentration of the gas-phase phosphorus source and the transport process are easier to adjust, which helps reduce the impact of uneven phosphorus release or localized overphosphating from the solid phosphorus source, and also improves the stability and repeatability of the preparation process.

[0030] Second, this invention determined an optimal phosphating temperature range through parameter screening. In this invention, the phosphating temperature of the Co / NiCo precursor is 280 °C to 320 °C, preferably 320 °C. Under the same phosphine concentration, flow rate, and phosphating time conditions, the adsorption conversion capacity of phosphine for CoP / NiCoP samples prepared at 280 °C, 300 °C, and 320 °C is approximately 173 mg·g⁻¹, respectively. -1 307 mg·g -1 and 373 mg·g -1 This indicates that 320 ℃ can achieve more complete phosphating conversion and higher phosphine utilization at relatively low temperatures.

[0031] Third, the CoP / NiCoP composite system obtained in this invention exhibits a higher phosphine adsorption and conversion capacity compared to single-phase phosphides. By adjusting the metal source composition in the precursor, this invention can prepare CoP, NiCoP, or CoP / NiCoP-related phosphide catalytic materials. Under the same phosphating condition of 320 °C, the phosphine adsorption and conversion capacities of NiCoP, CoP, and CoP / NiCoP samples are approximately 170 mg·g⁻¹. -1 255 mg·g -1 and 373 mg·g -1 The CoP / NiCoP ratio is approximately 119.4% and 46.3% higher than that of NiCoP and CoP, respectively.

[0032] Fourth, the catalyst obtained in this invention has good prospects for application in alkaline water splitting electrocatalysis. In a 1 mol / L KOH electrolyte, using CoP and NiCoP as control samples, the CoP / NiCoP ratio reaches 10 mA·cm⁻¹ in the hydrogen evolution reaction. -2 The overpotential at current density is approximately 110 mV, lower than approximately 157 mV for CoP and approximately 198 mV for NiCoP; the test potential required to reach a working current of 10 mA in the oxygen evolution reaction is approximately 0.923 V, lower than approximately 0.954 V for CoP and approximately 0.999 V for NiCoP, indicating that the CoP / NiCoP material structure is beneficial for improving the kinetics of alkaline water splitting reaction.

[0033] Fifth, this invention combines the benefits of phosphine adsorption-conversion with catalyst preparation. It utilizes phosphine as a gaseous phosphorus source, enabling it to participate in the precursor phosphating reaction and transform into metal phosphide materials. This process not only enables the preparation of CoP / NiCoP electrocatalysts but also provides a feasible approach for the resource utilization of phosphine. Furthermore, the catalyst exhibits good operational stability, with a voltage change of approximately 0.06 V after continuous operation for 24 hours using a chronovoltammetric method to test its overall water splitting stability. Attached Figure Description

[0034] Figure 1 This is a scanning electron microscope image of the CoP / NiCoP electrocatalyst prepared in Example 1 of the present invention. Figure 1 The left image is a low-magnification SEM image of the CoP / NiCoP electrocatalyst; Figure 1 The right image is a high-magnification SEM image of the CoP / NiCoP electrocatalyst.

[0035] Figure 2 The graph shows the adsorption and removal performance of phosphine by CoP / NiCoP, CoP, and NiCoP in the experiment of this invention. Figure 2The left figure shows the change in the adsorption and removal efficiency of phosphine by CoP / NiCoP over time under different phosphating temperatures. Figure 2 The right figure shows the change in the adsorption and removal efficiency of phosphine by different material systems at 320 °C over time.

[0036] Figure 3 The graph shows the electrocatalytic hydrogen evolution performance of CoP / NiCoP, CoP, and NiCoP in the experimental results of this invention. Figure 3 The left figure shows the hydrogen evolution reaction polarization curves of CoP / NiCoP, CoP and NiCoP in 1 mol / L KOH electrolyte. The horizontal axis is the potential relative to the reversible hydrogen electrode, and the vertical axis is the current density. Figure 3 The right figure shows CoP / NiCoP, CoP, and NiCoP at a current density of 10 mA·cm⁻¹. -2 Comparison of hydrogen evolution overpotentials at different times. Detailed Implementation

[0037] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Example 1: A method for preparing CoP / NiCoP electrocatalysts based on gas-phase phosphine phosphine treatment includes the following steps: (1) Preparation of Co / NiCo precursor S1: Weigh 108.0 mg Ni(NO3)2·6H2O and 216.0 mg Co(NO3)2·6H2O, add them to 60.0 mL isopropanol, stir to form a pink solution, then add 12.0 mL glycerol to the pink solution and continue stirring until the solution gradually changes from pink to a transparent and homogeneous mixed solution. S2: Transfer the transparent and homogeneous mixed solution obtained in step S1 to a 100.0 mL autoclave and maintain it at 160.0 ℃ for 6.0 h. After the reaction is complete, collect the product and wash it with alcohol by centrifugation at 7000 rpm for 10 min. Then, vacuum dry it for 12.0 h at 60 ℃ to obtain the primary powder product.

[0039] S3: The primary powder product obtained in step S2 was added to 60.0 mL of deionized water for hydrothermal treatment at 150.0 ℃ for 5.0 h. After hydrothermal treatment, the product was washed with alcohol by centrifugation at 7000 rpm for 10 min, and then vacuum dried at 60.0 ℃ for 12.0 h.

[0040] S4: The dried product was placed in a tube furnace and heated to 300.0 °C under a nitrogen atmosphere for 2 hours to obtain the Co / NiCo precursor.

[0041] (2) Preparation of CoP / NiCoP electrocatalyst S5: The Co / NiCo precursor obtained in Example 1 is sieved to obtain precursor powder with a particle size of 40-60 mesh.

[0042] S6: Weigh 50 mg of the sieved Co / NiCo precursor powder, place it in a tube furnace, and then heat the tube furnace to a temperature of 320 °C.

[0043] Before introducing phosphine gas, the tubular furnace is first purged with nitrogen. Once the furnace reaches the target temperature, a low-concentration phosphine gas mixture diluted with nitrogen is introduced into the furnace. The concentration of the phosphine gas is 1000 ppm, the flow rate is 100 mL / min, and the phosphating time is 180 min.

[0044] After the phosphating reaction is completed, the phosphine gas is stopped and the tube furnace is switched to a nitrogen protective atmosphere to allow it to cool naturally to room temperature. The phosphating tail gas is discharged after absorption or purification treatment, and the resulting product is collected to obtain the CoP / NiCoP electrocatalyst.

[0045] In this embodiment, phosphine gas is used as a gaseous phosphorus source to react with the Co / NiCo precursor, converting the precursor into a CoP / NiCoP phosphide catalyst. The phosphating reaction process can be regulated by controlling the phosphating temperature, phosphine concentration, flow rate, and phosphating time.

[0046] The obtained Co / NiCo precursor has a micro / nano structure that is beneficial for subsequent gas-phase phosphating; the CoP / NiCoP electrocatalyst obtained after gas-phase phosphating in Example 1 is as follows: Figure 1 As shown, it exhibits a distinct porous micro / nano structure with a surface displaying wrinkled, lamellar, or flower-like morphology. This structure is beneficial for increasing the contact area between the material and the electrolyte and reaction atmosphere, and provides more active sites for the electrocatalytic water splitting reaction.

[0047] Example 2: Preparation of CoP / NiCoP under different phosphating temperatures The Co / NiCo precursor was prepared according to the method in Example 1, and the obtained precursor was sieved into powder of 40-60 mesh.

[0048] 50 mg of Co / NiCo precursor powder was weighed and placed in a tube furnace. Under the same conditions as in Example 1, including phosphine concentration, phosphine flow rate, and phosphating time, the phosphating temperatures were set to 280 °C, 300 °C, and 320 °C, respectively, for gas-phase phosphating treatment.

[0049] In this process, the phosphine gas was a low-concentration phosphine mixture diluted with nitrogen, with a concentration of 1000 ppm and a flow rate of 100 mL / min. The phosphine treatment time was 180 min. After the reaction was completed, the phosphine gas supply was stopped, and the atmosphere was switched to nitrogen for cooling to room temperature. The phosphating tail gas was discharged after absorption or purification treatment, yielding CoP / NiCoP catalytic materials prepared under different phosphating temperature conditions.

[0050] like Figure 2 As shown, the CoP / NiCoP system exhibited certain removal capabilities for phosphine at 280 ℃, 300 ℃, and 320 ℃. Specifically, the phosphine adsorption conversion capacities of the samples prepared at 280 ℃, 300 ℃, and 320 ℃ were approximately 173 mg·g⁻¹, respectively. -1 307 mg·g -1 and 373 mg·g -1 The 320 ℃ sample maintained a higher PH3 removal efficiency over a longer testing period, indicating that appropriately increasing the phosphating temperature is beneficial to promoting the reaction and conversion between the precursor and phosphine.

[0051] The temperature screening results above indicate that when the phosphating temperature is below 320 °C, the phosphating conversion of the precursor to CoP / NiCoP is insufficient, resulting in a decrease in both the PH3 adsorption conversion capacity and the long-term removal efficiency. Therefore, this invention defines the feasible phosphating temperature range as 280 °C to 320 °C, and determines 320 °C as the optimal phosphating temperature to balance high PH3 utilization with low heat treatment energy consumption.

[0052] Effect Experiment: 1. Comparative preparation of CoP, NiCoP, and CoP / NiCoP: To further illustrate the influence of different metal compositions on material properties, precursors with different metal compositions were prepared according to the method in Example 1.

[0053] Among them, Co precursor was prepared without adding Ni source; NiCo precursor was prepared when the molar ratio of Ni source and Co source was adjusted to 1:1; Co / NiCo precursor was prepared according to the metal source composition of Example 1.

[0054] The different precursors were sieved to 40–60 mesh, and 50 mg of each was weighed and placed in a tube furnace. Phosphine gas-phase phosphating was then performed at 320 °C with a phosphine gas concentration of 1000 ppm, a phosphine gas flow rate of 100 mL / min, and a phosphating time of 180 min.

[0055] After the reaction is complete, the flow of phosphine gas is stopped, and the atmosphere is switched to nitrogen to cool to room temperature. The phosphating tail gas is discharged after absorption or purification treatment, yielding CoP, NiCoP, and CoP / NiCoP catalytic materials, respectively.

[0056] like Figure 2 As shown, under the same phosphating temperature of 320 °C, the PH3 adsorption conversion capacity of NiCoP, CoP, and CoP / NiCoP samples was approximately 170 mg·g⁻¹. -1 255 mg·g -1 and 373 mg·g -1 The capacity of CoP / NiCoP is approximately 119.4% and 46.3% higher than that of NiCoP and CoP, respectively, and it maintains a higher PH3 removal efficiency within the same test time, indicating that the CoP / NiCoP composite system has better reaction stability and conversion capacity in the phosphine adsorption and conversion process.

[0057] The above results indicate that although single CoP or NiCoP can also participate in PH3 adsorption and conversion, the formation of a CoP / NiCoP system can provide more reaction sites and gas transport channels through porous micro-nano structures, thereby improving both PH3 removal efficiency and capacity.

[0058] 2. CoP / NiCoP electrocatalytic water splitting performance test: The CoP / NiCoP electrocatalyst prepared in Example 1 was used to test its electrocatalytic water splitting performance. Meanwhile, the CoP and NiCoP prepared in Effect Experiment 1 were used as comparative samples of single-phase transition metal phosphides and tested under the same electrolyte, scan rate, and electrode area conditions.

[0059] The test electrolyte was a 1 mol / L KOH solution. The hydrogen evolution reaction performance of different catalytic materials was tested using linear sweep voltammetry, yielding hydrogen evolution reaction polarization curves for CoP / NiCoP, CoP, and NiCoP. Simultaneously, the oxygen evolution reaction performance of the above materials was tested, obtaining the corresponding oxygen evolution reaction polarization curves.

[0060] like Figure 3 As shown, CoP / NiCoP, CoP, and NiCoP all exhibit certain hydrogen evolution reaction activity. Among them, at 10 mA·cm⁻¹...-2 At the current density, the hydrogen evolution overpotential of CoP / NiCoP is about 110 mV, which is lower than that of CoP (about 157 mV) and NiCoP (about 198 mV), indicating that CoP / NiCoP has a lower hydrogen evolution reaction energy barrier at the same current density.

[0061] Further oxygen evolution reaction (OER) tests were conducted. At an operating current of 10 mA, the required test potential for CoP / NiCoP was approximately 0.923 V, lower than that for CoP (approximately 0.954 V) and NiCoP (approximately 0.999 V). Calculated using the commonly used reversible hydrogen electrode conversion method in a 1 mol / L KOH system, the corresponding OER overpotentials for CoP / NiCoP, CoP, and NiCoP were approximately 617 mV, 648 mV, and 693 mV, respectively. These results indicate that the CoP / NiCoP material prepared via the Co / NiCo precursor and phosphine gas-phase phosphating process exhibits good electrocatalytic activity in both hydrogen evolution and OER reactions.

[0062] 3. Overall water decomposition stability test of CoP / NiCoP: The CoP / NiCoP electrocatalyst prepared in Example 1 was used for a two-electrode overall water splitting stability test, with a 1 mol / L KOH solution as the test electrolyte. Using a chronopotentialostatic method, continuous testing was conducted at a constant current of 10 mA for 24 hours. The electrolytic cell voltage changed from approximately 1.71 V initially to approximately 1.77 V, a voltage drift of approximately 0.06 V, indicating that the CoP / NiCoP electrocatalyst exhibits good operational stability under alkaline overall water splitting conditions.

[0063] As demonstrated by the above embodiments, this invention can prepare CoP / NiCoP electrocatalysts through the construction of Co / NiCo precursors and gas-phase phosphine phosphine reaction. The method has clear process steps, controllable phosphating conditions, and can achieve phosphating conversion of the precursor within the temperature range of 280 ℃ to 320 ℃. Furthermore, the PH3 adsorption conversion capacity of the sample at 320 ℃ can reach approximately 373 mg·g⁻¹. -1 The values ​​were significantly higher than those of samples taken at 280 °C and 300 °C.

[0064] The obtained CoP / NiCoP material not only showed better PH3 removal performance than CoP and NiCoP single-phase samples during the phosphating process, but also exhibited good hydrogen evolution, oxygen evolution and overall water decomposition stability in alkaline electrolyte, indicating that it has application prospects in the fields of phosphine resource conversion and alkaline electrocatalytic water decomposition.

[0065] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing CoP / NiCoP electrocatalysts based on gas-phase phosphine phosphine treatment, characterized in that, Includes the following steps: S1: Add nickel source and cobalt source to isopropanol and stir to form a mixed solution. Then add glycerol to the mixed solution and continue stirring until the solution is transparent and uniform to obtain a transparent solution. S2: The transparent solution obtained in step S1 is transferred to an autoclave for a solvothermal reaction. After the reaction is completed, the product is washed and dried to obtain a primary powder product. S3: Add the primary powder product obtained in step S2 to deionized water for hydrothermal treatment. After the hydrothermal treatment is completed, wash and dry the product. S4: The product obtained in step S3 is placed in a tube furnace and heat-treated under a nitrogen atmosphere to obtain the Co / NiCo precursor. S5: The Co / NiCo precursor obtained in step S4 is sieved to obtain precursor powder; S6: Place the precursor powder obtained in step S5 in a tube furnace and perform gas-phase phosphating treatment under a phosphine atmosphere. After phosphating, cool to room temperature to obtain the CoP / NiCoP electrocatalyst.

2. The method for preparing CoP / NiCoP electrocatalyst according to claim 1, characterized in that, In step S1, the nickel source is Ni(NO3)2·6H2O, and the cobalt source is Co(NO3)2·6H2O; The molar ratio of Ni(NO3)2·6H2O to Co(NO3)2·6H2O is 1:(1-4); the volume ratio of isopropanol to glycerol is (3-8):

1.

3. The method for preparing CoP / NiCoP electrocatalyst according to claim 1, characterized in that, In step S2, the temperature of the solvothermal reaction is 140 ℃~180 ℃, and the reaction time is 4 h~8 h; The washing is performed by centrifugal washing with alcohol, and the drying is performed by vacuum drying at a temperature of 60.0 ℃ for 12.0 h.

4. The method for preparing CoP / NiCoP electrocatalyst according to claim 1, characterized in that, In step S3, the hydrothermal treatment temperature is 130 ℃~170 ℃, and the hydrothermal treatment time is 3 h~8 h; The washing is performed by centrifugal washing with alcohol, and the drying is performed by vacuum drying at a temperature of 60.0 ℃ for 12.0 h.

5. The method for preparing CoP / NiCoP electrocatalyst according to claim 1, characterized in that, In step S4, the heat treatment temperature is 250 ℃~350 ℃, and the heat treatment time is 2h.

6. The method for preparing CoP / NiCoP electrocatalyst according to claim 1, characterized in that, In step S5, the particle size of the precursor powder is 40-60 mesh.

7. The method for preparing CoP / NiCoP electrocatalyst according to claim 1, characterized in that, In step S6, the concentration of the phosphine gas is 1000 ppm to 1050 ppm, and the flow rate of the phosphine gas is 100 mL / min; The temperature of the gas phase phosphating treatment is 280 ℃~320 ℃, and the phosphating time is 120 min~200 min.

8. The method for preparing CoP / NiCoP electrocatalyst according to claim 1, characterized in that, In step S6, before introducing phosphine gas, the tubular furnace is purged with nitrogen; the phosphine gas is a low-concentration phosphine mixture diluted with nitrogen; after phosphating is completed, the introduction of phosphine gas is stopped, and the furnace is switched to a nitrogen protective atmosphere to cool to room temperature; the phosphating tail gas is discharged after absorption or purification treatment.

9. A CoP / NiCoP electrocatalyst prepared by the method according to any one of claims 1-8, characterized in that, The CoP / NiCoP electrocatalyst has a porous micro / nano structure with a surface exhibiting wrinkled, lamellar, or flower-like morphology.

10. The application of the CoP / NiCoP electrocatalyst of claim 9 in an alkaline electrocatalytic water separation hydrogen electrode, oxygen evolution electrode, or overall water splitting device, characterized in that, The CoP / NiCoP electrocatalyst is used for electrocatalytic hydrogen evolution reaction, oxygen evolution reaction and / or overall water splitting reaction under alkaline conditions.

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