Design Of Cobalt-based Heterogeneous Nanomaterials And Their Electrocatalytic Performance For Water Splitting

Hydrogen（H₂）,due to its high calorific value and pollution-free combustion products,is expected to become the main energy used by human society in the future.However,the high overpotential of both the oxygen evolution reaction（OER）at the anode and the hydrogen evolution reaction（HER）at the cathode of water electrolysis result in low energy conversion efficiency.Cobalt（Co）element possesses abundant reserves,low price,tunable d-band center and electronic structure.However,most of the Co-based catalysts display unsatisfied catalytic performance.The weak adsorption of metal Co to OER reaction intermediates and the strong adsorption to HER reaction intermediates lead to the limitation of its catalytic performance.Based on the research status and the existing problems,the main purpose of this thesis is to improve the activity of Co-based catalyst and atomic efficiency.A series of high-performance Co-based OER and HER catalysts are designed and prepared.The details are as follows:（1）In Chapter 3,the Co P@Fe OOH heterogeneous interface was constructed by interface engineering regulation to optimize the adsorption of intermediates at the interface.Moreover,nickel foam with well-developed pore structure was prepared as the base to improve the utilization of active sites and enhance mass transfer.（2）The development of new bifunctional catalysts with high activity and low cost is the key to achieve efficient hydrogen production from electrolytic water.In Chapter 4,Mo,P double-doped Co particle-coupled Ni（OH）₂nanosheet composite catalysts were prepared using the design ideas of double-atom doping and constructing heterogeneous interfaces.Experimental results showed that the composite structured catalyst exhibited efficient bifunctional catalytic performance in alkaline electrolytes.（3）In Chapter 5,the composite catalysts with Mo,P double-doped metal Co coupled with metal Ni particles were prepared based on the design idea of lattice matching to construct a stable heterojunction interface.The stable interfacial structure between metallic Ni and heteroatom-doped metallic Co not only accelerates the charge transfer,but also ensures the exposure of high-density active sites.In summary,different types of Co metal-based catalysts were developed by using interface engineering,doping,heterojunction construction and skeleton pore structure regulation strategy.These regulatory strategies significantly improve the activity and partial stability of Co-based catalysts,and provide guidance for the design of non-precious metal catalysts.