Synthesis And Electro-catalytic Performance Of Transition Metal Phosphide Nanomaterials For Hydrogen Evolution Reaction In Electrolysis Of Water

Due to its excellent properties,transition metal phosphide nanomaterials for hydrogen evolution reaction have been widely studied by electrochemical researchers.In this paper,a series of studies have been carried out on Ni-based,Fe-based phosphide nanocomposites and their electro-catalytic properties.The details of dissertation are summarized as follows:1.We focus on the effect of the phase and morphology of nickel phosphide on hydrogen evolution activity.The phases of the as-synthesized nickel phosphide nanoparticles could easily be controlled by changing the P:Ni precursor ratio.Changing reaction time and an intermediate step can further improve small-size nanoparticles close to pure Ni5P4 phase.Small-size Ni5P4 NPs supported on carbon exhibit superior HER activity compared to Ni12P5/C and Ni2P/C,which show a low overpotential of 103mV at 10 mA cm-2 with a low loading of 0.2 mg cm-2.This can be attributed to special structure and small size of Ni5P4 NPs.This study shows that the crystalline phase and NPs size are both key factors affecting the electro-catalytic properties.2.Iron phosphide-based materials have received extensive attention as promising non-noble-metal catalysts due to the low cost,high catalytic activity,and excellent stability.The influence of different metal dopings on electrocatalytic performance of such M-Fe-P/C(M=Co,Cu,Mn)hybrid catalysts were systematically investigated.Co substitution of Fe in FeP has a heavy influence on the HER performances,and CoFe2Px/C shows superb activity and only needs overpotential of 60 mV to drive 10 mA cm-2 with a low loading of 0.4 mg cm-2.The experimental results show that the formation of hollow structure is the key factor to improve the HER activity of iron phosphide,which is related to the particle size of precursor nanoparticles.