Controlled Synthesis Of Pt-based Nanocrystals In Water Solution System And The Investigation Of Their Electrocatalytic Performance

The excessive use of fossil fuel has led to severe environmental problems such as global warming,the rise of sea level,and the drastic reduction of biodiversity,which has a huge impact on the survival of human beings and other creatures.Therefore,developing new energy such as solar energy,wind energy and geothermal energy is the best methods to reduce the reliance on fossil fuel and mitigate the problems of environmental pollution.Electrochemical energy conversion technology,which converts between electrical energy and chemical energy,has been focused by researchers because of the advantage of cleanliness during the conversion process among the new technology in energy.Electrocatalysts can enhance the efficiency of energy conversion via improving the rate,selectivity,and efficiency of the electrocatalytic reaction.It is of significant importance to developing electrocatalyst with excellent performance in oreder to promote the commercial application of electrochemical energy conversion devices.Platinum-based materials are commonly used in electrocatalysts.However,the commercialization of energy conversion is impeded by the cost and scarcity of Pt.Developing the Pt-based catalysts with higher electrocatalytic performance and lower usage of Pt element via controlling the morphology,size and composition is focused among researchers.In this paper,two platinum-based materials are prepared by solvothermal method.In this paper,the platinum-based catalysts were synthesised on the principle of liquid phase reduction method.Exploring the catalyst catalyst performance improvement factors was aimed to achieve the best catalyst performance through controlling the system of catalyst synthesis.The specific research contents of this paper are as follows:(1)In the aqueous phase system,a one-step method was developed to synthesize platinum nanocrystals with branched structure.Electron microscope research confirmed that the size of the nanocrystals obtained by this technology was 28nm via adjusting the reaction temperature,reaction time and the amount of reducing agent,To further explore the factors that determine the morphology of platinum nanocrystals,electrocatalysis studies have confirmed that the platinum nanocrystals obtained by this technology exhibits superior catalytic performance than commercial platinum-carbon catalysts in the methanol oxidation reaction and oxygen reduction reaction.(2)On the basis of the previous research,the idea of improving the performance of the catalyst was further broadened.In the system for synthesizing platinum nanocrystals,copper nanocubes with narrow size distribution interval and high morphological consistency was introduced.The copper-platinum alloy with branched structure was obtained by regulating the rate of galvanic replacement of freshly reduced platinum atoms and copper.Electrocatalytic studies confirmed that the copper-platinum alloy with branched structure synthesized at 80? showed the best catalytic performance in both hydrogen evolution reaction and methanol oxidation reaction.