Preparation And Electrocatalytic Performance Of Noble Metal-Loaded Transition Metal Compound Nanosheets

In recent years,the development of clean energy in an efficient manner has become a hot topic for researchers.Electrocatalytic reactions have gained increasing attention in this field due to their wide application and cleanliness.And the choice of catalyst is the key point to improving the catalytic effect of electrocatalytic reaction.In this process,the catalytic performance and cost are two main factors need to be considered.In this thesis,we combine the excellent catalytic properties of precious metals with the low cost of transition metal oxides to design a series of noble metal-loaded transition metal compound nanosheets.The transition metal compounds have nanosheet structures that rich in active sites,thereby ensuring the catalytic activity of the transition metal substrate.After the transition metal substrate is combined with the noble metal,an electrochemical reaction catalyst having both high performance and low cost is obtained.Subsequently,the morphology and components of the synthesized catalyst were characterized and applied in different electrocatalytic reactions in order to provide new ideas for the design of various electrocatalytic reaction catalysts.The main research works are summarized as follows:1.A selective reduction oxidation strategy was used to prepare silver-doped cobalt-based hydroxide nanosheets with a uniform structure.The material exhibited excellent catalytic ability for electrocatalytic oxygen evolution（OER）.The initial cobalt hydroxide nanosheets can fully expose a large number of active sites,and the overpotential at a current density of 10 mA/cm² is 350 mV（vs.RHE）.Due to the increased conductivity of the material after the silver nanoparticles were added,its overpotential was further reduced to 270 m V（vs.RHE）.At the same time,the method can effectively control the content of silver added in the material and achieve the regulation of the catalytic performance of the material.Not only that,the method also has the advantages of simple operation,mild reaction conditions,and large output.At the same time,the addition of silver also played a significant role in improving the OER catalytic performance of other cobalt containing double hydroxides,showing good universality.2.Au-SnO₂-CNTs composites were synthesized in one step by using a water bath heating method.In this method,the SnO₂ nanosheets were successfully synthesized on the surface of carbon nanotubes（CNTs）,and the loading of gold particles could be achieved by adding chloroauric acid in the reaction process.This material is used in the research of electrocatalytic carbon dioxide reduction（CRR）.In a small reduction potential range,the ratio of CO to H₂ in the product can be controlled in a large range,and it has a high Faraday efficiency,which provides a new idea for the synthesis of syngas by CRR reaction.3.First,titanium dioxide arrays with different morphologies were formed on the surface of commercial titanium wafers by hydrothermal method.Subsequently,titanium wafers with a two-dimensional array of morphologies were selected for subsequent modification,and gold nanoparticles were uniformly grown on the surface of titanium wafers by means of electrodeposition.This material is applied to the research of electrocatalytic nitrogen reduction（NRR）.The titanium dioxide array containing gold on the surface exhibits great electrocatalytic ammonia production capacity,and its ammonia production rate can reach a maximum of 6.668?g/h/cm²_cat,at the same time,the gold content on the surface of the titanium sheet can be controlled and it has a significant impact on the ammonia production performance of the material.Besides,in this research,the titanium sheets are used as substrates,and the product can be directly used as a working electrode,which makes it easier to implement commercial applications.