Studies On Construction Of Ni-Based High-Efficiency Electrocatalysts And Their Solar-Driven Water Splitting Performance

Currently,human society is facing serious energy crises and environmental pollution problems,so it is important to seek a green and clean energy source to replace traditional fossil fuels.Hydrogen energy has attracted a lot of attention from researchers because of its advantages such as high combustion value and storage.Traditional hydrogen production methods cause environmental pollution.In contrast,the use of solar-driven photocatalytic water splitting for hydrogen production is a green,non-polluting,and sustainable means with more potential application prospects.The development of solar-driven overall water splitting reaction has made important progress in recent decades,however,it is still limited by the low efficiency of solar-to-hydrogen conversion,poor stability,and high cost of precious metal catalysts,which is an important bottleneck limiting its large-scale practical application and development.Therefore,the realization of efficient,stable,and low-cost solar-driven hydrolysis reactions is of great scientific research and practical application value.Compared with expensive precious metals,nickel-based materials have the advantages of abundant reserves,low-cost,easily tunable electronic structure,high electrical conductivity,and good corrosion resistance,which have broad application prospects in the field of electrocatalytic water splitting.By exploring nickel-based materials,it is expected to develop electrocatalysts for water splitting with excellent performance and low cost.Based on this,we have developed superior performance hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)electrocatalyst based on the conformational relationship between electronic structure and catalytic performance using nickel-based materials,further coupled with III-V photovoltaic semiconductor materials,and designed solar-driven photochemical conversion devices to achieve efficient,stable and low-cost solar-driven hydrolysis reaction performance.The main research of this thesis is as follows:In chapter 1,we first describe the overview of the solar-driven hydrolysis reaction,then introduce the mechanism of electrocatalytic overall water splitting reaction and the research progress of nickel-based water splitting electrocatalyst,and finally introduce the significance of the topic and the research content of this thesis because of the current research problems.In Chapter 2,to address the current problem of poor stability of solar-driven hydrolysis,we prepared MoNi4/MoO2 bifunctional electrocatalysts with nanowire arrays by hightemperature reduction method from the conformational relationship of nickel-based water splitting electrocatalysts.MoNi4/MoO2 has a high electrochemical active area,efficient electrocatalytic hydrogen evolution and oxygen evolution half reaction active and stability,thus the MoNi4/MoO2 bifunctional catalyst exhibited excellent electrocatalytic hydrolysis performance and long-term stability.By spatially coupling with triple-junction III-V photovoltaic semiconductors,a solar-driven water splitting reaction system was built to achieve an efficient and stable solar-driven hydrolysis reaction performance.Finally,the integrated artificial leaf system without wire coupling was further constructed to achieve an efficient and stable solar-driven water splitting reaction.In Chapter 3,to address the current problem of low efficiency of solar-driven water splitting,we improve the stability and the number of active sites of NiFe base double hydroxides(NiFe-LDHs)by improving the kinetically slow oxygen evolution reaction process in water splitting reactions.The activity and stability of the electrocatalytic OER were improved by annealing the hydrothermally synthesized NiFe-LDHs.By combining with the HER electrocatalyst MoNi4/MoO2 in Chapter 2,highly efficient MoNi4/MoO2‖NiFe-LDHs electrochemical water splitting full cells were prepared.Further coupled with a triple-junction photovoltaic semiconductor,a solar-driven water splitting reaction system was built to achieve efficient and stable hydrolysis reaction performance for a long time.In Chapter 4,we present an overall summary of the thesis.The research content,main innovation points,and problems of this thesis are introduced,and corresponding solutions are also proposed,and the next work has prospected.