The Study On Novel Noble Metal-based Nanocatalysts And Their Performance For Hydrogen Evolution Reaction

In order to reduce the dependence on fossil fuels such as coal,petroleum and natural gas,and the increasingly serious environmental pollution,there is an urgent need to replace fossil fules with clean,efficient and renewable energy.As a renewable clean energy source,hydrogen energy has the advantages of abundant reserves,high combustion efficiency,and no pollution and has received a huge amount of attention.Hydrogen production by electrolyzing water molecule will be the research focus because of its unsophisticated system and high purity of hydrogen produced.The Pt-based catalyst is currently the state-of-the-art electrocatalyst for hydrogen evolution reaction(HER),but its scarcity and high cost limit its large-scale industrial applications.Therefore,there is an urgent need to develop electrocatalysts with low Pt content and high HER catalytic performance.Methods like preparing Pt-based alloy catalysts with high-index facets(HIFs),smaller nanoparticle size,and loading them on graphene or graphene derivative supports have been proven to be effective to improve the catalytic performance of Pt-based catalysts.In this paper,PtNi concave nanocubes(CNCs)supported on porous graphene(PG)were synthesized by a one-step hydrothermal method,and the morphology(size and concave degree)of PtNi CNCs was controlled by changing the amount of PG added.It was found that the PtNi concave cubes on the PG were exposed with HIFs.The more the PG was added,the smaller the size of concave cubes and the concave degree.Finally,the HER performance of as-prepared samples was tested in acidic media.The results showed that PtNi/10PG CNCs has the best HER activity(?31 m V of overpotential at a current density of 10 m A cm^-2)and the smallest Tafel slope(18 m V dec^-1).Stability test also showed that it has excellent stability.The experimental results show that porous graphene has an important and positive role in promoting the electrocatalytic HER activity of the composite material.The excellent HER performance may be due to the following reasons:the distict CNC morphology with HIFs,the smaller CNC size,the synergistic effect between the PtNi alloy and the PG support,and superior support properties of PG.