Preparation And Properties Study Of Non-noble Metal-based Electrolytic Water Energy Materials

In recent years,the large consumption of fossil fuels and the resulting serious environmental pollution problems have attracted increasing attention.Therefore,the research and development of clean and renewable energy to replace fossil fuels has a significant role in promoting the solution of energy exhaustion.Hydrogen is considered as the most promising new energy source because of its clean,renewable and high energy density.At present,electrochemical water decomposition technology has been a hot research topic in the field of hydrogen energy technology because of its simple operation,low energy consumption,high purity of products and environmental friendliness.However,since water decomposition to hydrogen is a thermodynamic process requiring energy absorption,it is necessary to reduce the energy consumption of the two semi-reactions?hydrogen evolution reaction and oxygen evolution reaction?in water decomposition by studying the electrocatalysts with excellent performance.Noble metal-based materials are the most excellent electrocatalysts at present,but because of their high price and scarcity of reserves,the application of precious metals as electrocatalysts in industry is limited.Therefore,the development of high-activity electrocatalysts with abundant reserves and low cost is very important for the research of hydrogen energy to replace fossil fuels.The research work in this paper provides a new idea for the design and preparation of high-efficiency electrolytic water electrode materials for hydrogen production.Specific research contents are as follows:?1?Study on preparation and properties of interface engineering of crystalline/amorphous Co₂P/CoMoP_x nanostructure as efficient electrocatalysts for hydrogen evolution reaction.The development of catalytic electrodes for hydrogen production from electrolytic water has become an effective strategy to solve the energy crisis and environmental problems.Transition metal phosphides with abundant reserves are increasingly used to prepare hydrogen evolution catalytic electrodes due to their unique chemical properties.Herein,an interface engineering of crystalline/amorphous Co₂P/CoMoP_x film was facilely prepared on nickel foam?NF? at room temperature by one-step electrodeposition.When the current density is 10 mA·cm^-2,the hydrogen evolution overpotential is -22 mV and the Tafel slope is 87.2 mV·dec^-1,which is close to the value of Pt/C.It proves that the Co₂P/CoMoP_x-NF electrode has high catalytic performance for hydrogenevolution.The stability testshowedthat the Co₂P/CoMoP_x-NF electrode has good catalytic stability.In addition,the effect of the interface between crystalline and amorphous phases in the electrode materials on the catalytic performance of hydrogen evolution was discussed by changing the electrodeposition parameters-current density.This study provides an effective strategy for the development of non-noble metal catalysts with such unique structure for hydrogen evolution.?2?Study on the preparation and properties of iron-doped cobalt phosphide bifunctional electrocatalysts with high efficiency and stability.Cobalt phosphide has attracted extensive research interest due to its good catalytic activity for hydrogen evolution.Compared with single hydrogen evolution or oxygen evolution electrocatalysts,bifunctional electrocatalysts have attracted much attention because they can simultaneously reduce the overpotential of hydrogen evolution and oxygen evolution in the same electrolyte environment,thus reducing the energy consumption of the whole electrolytic water.Researchers have found that the electronic structure of the active center can be changed by metal doping,and the combination of HER active material and OER active material on the same electrode material is conducive to the developmentofbifunctionalelectrocatalyticmaterials.Byoptimizingthe electrodeposition parameters,the Fe-Co-P film was prepared by one-step electrodeposition on the surface of nickel foam,which has good HER activity of cobalt phosphide and increased OER activity due to the introduction of iron.The electrochemical tests show that the ternary Fe-Co-P electrode as cathode and anode in the electrolytic cell exhibits excellent performances of HER,OER and overall electrolytic water.When the current density is 10 mA·cm^-2,the HER overpotential is -27mV,the OER overpotential is 280 mV and the electrolytic voltage is 1.56 V.This performance is close to that of Pt/C-IrO₂ combination.It is proved that iron doping can increase the OER performance of the electrocatalysts.The ternary Fe-Co-P electrode with good overall electrolytic water performance was successfully prepared.In addition,we discussed the effect of regulating the content of doped iron on the OER performance of electrocatalysts.This study provides a new idea for the development of non-noble metal bifunctional electrocatalysts with both HER and OER activities.?3?Study on the preparation and properties of self-supporting Ni/NiSP_x bifunctional electrocatalytic electrode with high efficiency and stability in simulated industrial environment.At present,the industrial hydrogen production by electrolyzing water needs to provide 200-400 mA·cm^-2 current density for catalytic reaction under high battery voltage of 1.8-2.4 V.The hydrogen yield is less than 5% under such huge energy consumption.Therefore,we urgently need to develop bifunctional electrocatalysts for hydrogen production from electrolytic water under high current density in industrial environment.In this paper,on the basis of accurately adjusting the electrochemical deposition parameters to control the catalytic performance of bifunctional electrocatalysts under high current density,a Ni/NiSP_x bifunctional electrocatalyst electrode was prepared on the surface of foamed nickel by simple and rapid electrodeposition.The electrochemical tests show that the Ni/NiSP_x bifunctional electrocatalytic electrode exhibits more efficient overall electrolytic water catalytic performance in simulated industrial environment than the current catalytic electrode.The electrolytic potential of the Ni/NiSP_x bifunctional electrocatalytic electrode is 2.38V when the current density of the electrolytic water is 1000 mA·cm^-2.At present,the electrolytic potential of the industrial electrocatalysts is only 400 mA·cm^-2 when the electrolytic voltage is 2.4 V.At the high current density of 1000 mA·cm^-2,it can stabilize electrolytic catalysis for more than 30 hours,which provides an attractive prospect for the practical application of hydrogen production from industrial electrolytic water.