Solution Process For Transition Metal Phosphides And Transition Metal Phosphides-Based Heterostructures And Their Electrocatalytic Performance In Hydrogen Evolution Reaction

The overuse of fossil fuels has brought about the depletion of resources and the deterioration of the environment.As an ideal carrier of renewable and clean energy,hydrogen has been widely studied because of its high calorific value,environmental protection and easy storage.It is one of the most potential substitutes for traditional fossil energy.At present,most industrial hydrogen production methods are still coal gasification,steam methane reforming which still need to consume a lot of fossil fuels.The hydrogen evolved by electrocatalytic water splitting reaction has become an attractive research topic because of it is simple and convenient.The by-product pollution is free and the purity of hydrogen after separation is very high.Platinum and other noble metal catalysts are always the most efficient catalysts in Hydrogen Evolution Reaction（HER）,but their scarce storage limits the wide use.Therefore,it is very important to find cheap,earth-abundant and high-performance catalysts to replace precious metal catalysts.In recent years,transition metal phosphides are considered to have good application potentials due to their unique electronic structure and high electrocatalytic activities.And their performances can be further improved by constructing heterostructures with other elements.Based on the above ideas,a unique chemically transforming method was adopted in this paper.In the oil phase colloidal solvent,transition metal oxide particles were used as the precusors and were phosphatized into transition metal phosphides（TMPs）.Then,the as-obtained TMPs were selected as templates to synthesis heterostructures.The related characterization and performance measurements were carried out.The details are as follows:（1）Silver nanoparticles（AgNPs）were selectively grown on two kinds of cobalt phosphide nanorods（Co₂P NRs）which were chemically transformed Co₂P NRs and Co₂P NRs directly phosphated by Co（III）acetylacetonate[CO（acac）₃]respectively.By simply changing the ratio of different surfactants,we can control the location of AgNPs on different regions of Co₂P NRs,achieving the single,double and multiple AgNPs-decorated Co₂P NRs（Ag（S）-Co₂P、Ag（D）-Co₂P and Ag（M）-Co₂P）.Remarkably,Ag（M）-Co₂P exhibited a higher catalytic activity for the hydrogen evolution catalysis（HER）owing to the more heterointerfaces and the more active sites:a low overpotential of 67m V at 10m A cm^-2,and a small Tafel slop of 38m V dec^-1 in acid electrolyte.Moreover,no evidence of deactivation after long-term operation was observed.（2）Tungsten trioxide nanoparticles（WO₃NPs）were selected as the precursor to synthesis tungsten phosphide nanospheres（WP NSPs）via chemically transformed method.We controlled the timing of the reaction in order to explore the process phosphidation.Ni₂P and Co₂P were chosen to grow on the surface of WP NSPs to achieve WP-Ni₂P and WP-Co₂P heterostructures,which also exhibited excellent HER performances.