Theoretical Design Of Hydrogen Evolution Catalyst Based On The Cu₃P Systems And Correlative Study On The Catalytic Mechanisms

With the extensive exploitation and misuse of fossil fuels,we have to confront the problems of environmental pollution and fossil fuels depletion.Therefore,it is vital to develop the clean and renewable alternative to fossil fuels.As a primary carrier,hydrogen energy has been highly anticipated to be a competitive solution to effectively address these problems,in view of its many virtues including the high gravimetric energy density,abundant source and non-pollution of reaction products.The major research object of producing hydrogen energy is the catalytic performance of electrocatalysts for hydrogen evolution reaction?HER?.In this work,we will systematically investigate the structures and hydrogen evolution reaction?HER?catalytic activities for pristine and Ni-doped Cu₃P systems by using first-principles DFT computations.Our calculated results reveal that the?11?0?surface can be the one with the most exposure for Cu₃P structure.The calculated free energy values of H*(?G_H*)are in the range of 0.012 to 0.320 e V,reflecting the HER activity on the?11?0?surface,which is consistent with the experimentally reported result.Our computed results also reveal that the top sites over P atoms as well as the bridge and hollow sites composed of Cu atoms can make the main contribution to the HER activity on the?11?0?surface,and the hollow sites(?G_H*?0 e V)can serve as the most active sites,due to the considerably flexible structure feature.Based on the calculated results of pristine Cu₃P,we have proposed an effective strategy through doping Ni to significantly improve the HER catalytic activity on the?11?0?surface by effectively optimizing the adsorption state of H*,based on the case that Ni and Cu have the opposite ability to bind with H.All these doped systems can uniformly possess the high HER activity,and particularly some doped structures with the appropriate Ni-atom number can even exhibit the considerably high HER activity over a wide range of H coverage,indicating the more excellent c atalytic performance.It is worth mentioning that the surface-metal-atoms for these Ni-doped systems can still exhibit the flexible behavior,which can be also beneficial for realizing the high HER activity.These fascinating theoretical insights at the atomic level can be advantageous for achieving the high-efficient nonprecious HER electrocatalysts based on the copper phosphide and even other transition metal phosphides in the near future.