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CN-121976222-A - NF/p-CoFeMoO of ultrathin porous nanosheet structure4Preparation method of NSs catalyst and application of NSs catalyst in photovoltaic hydrogen production

CN121976222ACN 121976222 ACN121976222 ACN 121976222ACN-121976222-A

Abstract

The invention provides a preparation method of an ultrathin porous CoFeMoO 4 -based nano-sheet electrocatalyst and application of the catalyst in a photovoltaic-water electrolysis hydrogen production system. According to the invention, fe element is introduced through solvothermal treatment and surface engineering, and meanwhile, the ultrathin nanosheet catalyst with a mesoporous structure is constructed, so that the ultrathin nanosheet catalyst shows excellent oxygen evolution reaction activity and stability. The Co and Fe elements in the catalyst have moderate adsorptivity to oxygen evolution reaction intermediates, and the multi-strategies such as electronic engineering and structural engineering improve the specific surface area, the activity of active sites and the ion/electron transmission rate of the catalyst, and obviously reduce overpotential and energy loss. The catalyst realizes high solar-hydrogen energy conversion efficiency and stability by coupling the photovoltaic and water electrolysis systems and taking a commercial monocrystalline silicon thin film battery as the only energy input. The technology has simple synthesis steps, does not have noble metal participation, realizes high-efficiency and stable green hydrogen energy production, and can synchronously generate clean fuel under the mild condition by solar drive.

Inventors

  • YI XINLI
  • LI DEJIANG
  • XIONG MIAO

Assignees

  • 三峡大学

Dates

Publication Date
20260505
Application Date
20260209

Claims (10)

  1. 1. The preparation method of the NF/p-CoFeMoO 4 -NSs catalyst with the ultrathin porous nano sheet structure is characterized by comprising the following steps: Step 1, preparing NF/CoFeMoO nH 2 O-NSs nano-sheets, namely dissolving Co (NO 3 ) 2 ·6H 2 O, feCl 2 ·4H 2 O and Na2MoO 4 ·2H 2 O) in a certain proportion in deionized water, uniformly stirring, fully immersing the washed foam nickel into the solution, transferring the solution into a polytetrafluoroethylene lining high-pressure reaction kettle, and obtaining an NF/CoFeMoO 4 ·nH 2 O-NSs precursor after hydrothermal reaction; Step 2, preparing an acid solution, namely dissolving a certain amount of acid in DMF, and dispersing the acid solution by adopting ultrasonic to obtain a transparent solution; And 3, preparing NF/p-CoFeMoO 4 -NSs nano sheets, namely fully immersing the NF/CoFeMoO 4 ·nH 2 O-NSs precursor into an acid solution, integrally transferring the acid solution into a polytetrafluoroethylene lining high-pressure reaction kettle, performing solvothermal reaction to obtain a product, and performing natural cooling, washing and drying and high-temperature heat treatment on the product to obtain the NF/p-CoFeMoO 4 -NSs electrocatalytic material.
  2. 2. The method for preparing the NF/p-CoFeMoO 4 -NSs catalyst with the ultrathin porous nanosheet structure according to claim 1, wherein in the step 1, the molar ratio of Co (NO 3 ) 2 ·6H 2 O to FeCl 2 ·4H 2 O) is 0.4-0.6, the hydrothermal reaction temperature is 120-160 ℃, and the reaction time is 3-6 h.
  3. 3. The method for preparing NF/p-CoFeMoO 4 -NSs catalyst having ultra-thin porous nanosheet structure according to claim 1, wherein in the step 2, the acid is selected from any one of terephthalic acid, m-methylbenzoic acid, 3-methoxy-4-pyridinecarboxylic acid, pyridine-2, 5-dicarboxylic acid, 5- (4-carboxyphenyl) picolinic acid.
  4. 4. The method for preparing an NF/p-CoFeMoO 4 -NSs catalyst having an ultrathin porous nanosheet structure according to claim 3, wherein the concentration of the acid is 0.004~0.01 mol mL -1 .
  5. 5. The method for preparing an NF/p-CoFeMoO 4 -NSs catalyst having an ultrathin porous nanosheet structure according to claim 1, wherein in the step 3, the solvothermal condition is heating at 150-180 ℃ of 10-12 h.
  6. 6. The method for preparing the NF/p-CoFeMoO 4 -NSs catalyst with the ultrathin porous nanosheet structure according to claim 1, wherein in the step 3, washing and drying conditions are that DMF is adopted for washing, and then drying is carried out in a vacuum drying oven at 50-70 ℃ to obtain a product.
  7. 7. The method for preparing the NF/p-CoFeMoO 4 -NSs catalyst with the ultrathin porous nanosheet structure according to claim 1, wherein the calcining condition in the step 3 is that the catalyst is heated to 350-500 ℃ from room temperature at a heating rate of 2-5 ℃ min -1 in pure argon atmosphere, and the catalyst is kept at the temperature of 2-4 h.
  8. 8. An NF/p-CoFeMoO 4 -NSs catalyst having an ultrathin porous nanosheet structure, prepared by the method of any one of claims 1-7, wherein the nanosheet of the NF/p-CoFeMoO 4 -NSs catalyst has a thickness of about 1.4 nm, an average pore diameter of 2-6 nm, and a2 theta of p-CoFeMoO 4 -NSs material in xrd data of about 13 、23 、25 、26 、28 The characteristic diffraction peaks of (a) correspond to the (021), (002), (-311), (-131) and (-222) crystal planes of monoclinic CoMoO 4 (JSPDS No. 21-0868), and the interplanar spacing of the core characteristic crystal plane (002) is about 0.33 nm.
  9. 9. Use of an NF/p-CoFeMoO4-NSs catalyst prepared by the method of any one of claims 1-7 in the production of hydrogen by photovoltaic-coupled electrolysis of water.
  10. 10. The use of NF/p-CoFeMoO 4 -NSs catalyst according to claim 9 in the production of hydrogen by photovoltaic-coupled electrolysis of water, characterized in that the specific step of using NF/p-CoFeMoO 4 -NSs catalyst for photovoltaic-driven alkaline hydro-electric desorption oxygen activation to produce hydrogen comprises the steps of: Step 1, adding a certain amount of electrolyte solution into an electrolytic tank, and then taking NF/Pt and NF/p-CoFeMoO 4 -NSs as a cathode and an anode respectively; Step 2, sealing and degassing the electrolytic cell to ensure that the electrolytic cell is in a negative pressure state; And step 3, connecting the monocrystalline silicon thin film battery to an electrolytic cell, radiating the battery by using an AM 1.5 solar simulator, and generating electric energy to drive electrolyzed water to prepare hydrogen and oxygen.

Description

Preparation method of NF/p-CoFeMoO 4 -NSs catalyst with ultrathin porous nano sheet structure and application of NF/p-CoFeMoO 4 -NSs catalyst in photovoltaic hydrogen production Technical Field The invention belongs to the technical field of electrochemical catalysis and new energy materials, and particularly relates to a preparation method of an NF/p-CoFeMoO 4 -NSs catalyst with an ultrathin porous nano sheet structure and application of the NF/p-CoFeMoO 4 -NSs catalyst in the aspect of hydrogen production energy conversion by photovoltaic coupling electrocatalytic water decomposition. Background Hydrogen energy is widely regarded as an ideal clean energy source for replacing fossil fuel because of the advantages of high energy density, zero carbon emission of combustion products and the like. The electricity generated by renewable energy sources (such as solar energy and wind energy) is used for driving water electrolysis to prepare green hydrogen, and the green hydrogen is one of core paths for realizing deep decarburization of an energy system. Among the water electrolysis technologies, alkaline water electrolysis technology has the greatest potential for large-scale application due to the relatively mature technology and low cost. However, the large-scale commercialization of alkaline water electrolysis still faces two key challenges, namely that firstly, the oxygen evolution reaction of the anode is a complex process involving four electron transfer, the kinetics are slow, the overpotential is high, and the bottleneck for restricting the improvement of the full hydrolysis efficiency is formed. Currently, the most advanced OER catalysts still rely heavily on noble metals such as iridium, ruthenium and their oxides, the high cost and scarcity in the crust of the earth greatly limiting the economics and popularity of the "green hydrogen" technology. Secondly, the energy coupling efficiency between the electrolytic tank and the fluctuation renewable energy source (such as photovoltaic) is low, and the solar energy-hydrogen energy conversion efficiency of the whole system is far lower than a theoretical value due to energy loss caused by mismatching of current-voltage characteristics. Transition metal-based oxides, such as cobalt-based and iron-based materials, are considered ideal candidates for replacing noble metal catalysts (e.g., irO 2, RuO2) in the field of basic Oxygen Evolution (OER) electrocatalysis due to their high earth abundance, low cost, and tunable electronic structure. Among them, cobalt molybdenum oxide (CoMoO 4) exhibits great potential for application due to its inherent electrochemical activity, various oxidation states, and good chemical stability. In addition, by constructing three-dimensional nanostructures, active sites can be effectively exposed and electron transport and gas release facilitated, which provides a viable strategy for developing efficient non-noble metal electrodes. However, the combination properties of the current catalysts based on CoMoO 4 or its simply doped derivatives still have difficulty in meeting the requirements of industrial applications. This is mainly due to two core bottlenecks, one of which is the lack of intrinsic activity. Pure CoMoO 4 is not enough optimized on the adsorption/desorption energy barrier of the OER reaction intermediate, and the intrinsic catalytic activity of the pure CoMoO 4 still has a larger improvement space. Although the traditional hetero atom doping can regulate and control an electronic structure to a certain extent, it is often difficult to ensure the full exposure of active sites while obviously improving the intrinsic activity. Secondly, mass transfer and stability challenges. Many researches have focused on constructing nanostructures to increase specific surface area, but the formed nanoplatelets tend to be too dense or uneven in thickness, resulting in low utilization of internal active sites, and oxygen bubbles generated under high OER current density are difficult to rapidly desorb, blocking active sites and possibly damaging catalyst structure, resulting in performance decay. More importantly, the existing material design strategies often consider electronic structure regulation and microstructure engineering as two relatively independent optimization directions. For example, pure Fe doping can improve intrinsic activity, but can negatively affect conductivity and stability of the material, while pure mesoporous structure can increase specific surface area, but cannot solve the fundamental problem of lower activity of each site, so that the performance of the catalyst is improved to have obvious upper limit, and the synergistic multiplication of activity, stability and mass transfer efficiency is difficult to realize. Aiming at the challenges, the invention provides a synergic strategy of electronic engineering and structural engineering, and an iron-doped mesoporous cobalt-molybdenum oxide ultrathin nanosheet elect