The Synthesis Of Self-supported Transition Metal Compound Nanostructures And Their Electrocatalytic Activity In Hydrogen Evolution Reaction

Because of growing concerns about energy shortages and environmental pollution,considerable efforts have been devoted to exploiting renewable clean new energy resources.Among the many clean energy sources,hydrogen is considered one of the most promising new energy sources in the future.Meanwhile,electrocatalytic water splitting to produce hydrogen is considered the cleanest,most sustainable and large-scale hydrogen generation technology.More efficient and cheaper electrocatalysts are required for the electrolysis of water in order to reduce energy consumption.Currently,Pt-group noble metal materials have been proven to be the most active electrocatalysts for the hydrogen evolution reaction?HER?,while high cost and scarcity limit their wide-spread application in industrial.Therefore,it is a key challenge to explore highly efficient,low-cost and high storage capacity non-noble electrocatalysts.In this paper,a facile and feasible method for the synthesis of highly active electrocatalysts,including amorphous ternary Ni-Co-P film?Ni-Co-P/NF?,ultra-long mixed-phase Ni-P nanowire arrays?Ni-P NWs/Ti?and porous MoC_x nanoparticles film?MoC_x/CFP?.Meanwhile,the electrocatalytic hydrogen evolution performance has been studied for these electrocatalysts.The corresponding works in this paper are listed as follows:?1?Amorphous ternary alloy Ni-Co-P film was loaded on nickel foam.The nickel salt,cobalt salt and phosphate are used as raw materials to obtain the electrocatalyst by one-step synthesis at low temperature.The catalyst shows a small overpotential of 125 mV for the current density of 20 mA cm^-2 in the alkaline media,and it could stably produce hydrogen for at least 25 h.Meanwhile,the influences of the metal source concentration,the sodium hypophosphite concentration and the pH value of the solution on the electrocatalytic hydrogen evolution performance were also investigated.?2?Utra-long mixed-phase Ni-P nanowire arrays were grown on Ti plate.Firstly,ultra-long Ni nanowire arrays were grown on the Ti plate substrate by electroless deposition method under magnetic field,and then a mixed phase Ni₅P₄-Ni₂P-NiP₂ nanowire arrays was obtained by low-temperature phosphorization.The catalyst shows a small overpotential of only 96 mV for the current density of 20 mA cm^-2 in the acidic media,and it could stably produce hydrogen for at least 25 h.Moreover,the prepared catalyst can be also used for electrocatalytic hydrogen evolution reaction in alkaline media.The overpotential at the current density of 20 mA cm^-2 is 153 mV in alkaline media.In addition,the effects of different phosphorization temperature on the hydrogen evolution performance were also studied.?3?Porous MoC_x nanoparticles film was grown in-situ on carbon fiber paper.The Mo+PVP precursor film was firstly prepared by dip-coating method,and then the final catalyst was obtained through high-temperature carbonization process.The prepared catalyst exhibits highly electrocatalytic activity in both acidic and alkaline media,a overpotentials of 75 and 58 mV at current densities of 20 mA cm^-2 in both acidic and alkaline media,respectively.It could stably produce hydrogen for at least 25 h.Moreover,the effects of different carbonization temperatures,the amounts of different carbon precursor,and different loading mass on the hydrogen evolution performance were also investigated.