Preparation Of Vanadium-cobalt (nickel) Binary Metal Nitrogen (phosphorus, Sulfur) Compound And Electrolysis Water Performance

The massive burning of traditional fossil fuels such as coal,oil and natural gas has brought serious environmental pollution and resources shortage problems,which has forced scientists to develop environmental pollution,sustainable energy resources and energy storage devices.In fact,electrocatalytic water splitting is a green,low cost and high-income solving strategy to produce hydrogen.In order to reduce energy consumption and improve reaction efficiency,efficient and stable electrocatalysts are necessary to improve the reaction rate.Vanadium?V?belongs to the pre-transition metal,which has low cost,variable valence states and high reserves,and becomes a candidate material for electrocatalysts.Through literature investigation and experimental researches,it is found that the catalytic ability of bimetallic electrocatalysts obviously superior to that of single metal compounds.Co,Ni,Fe and other iron elements,due to their unique electronic arrangement and abundant reserves,have been widely concerned by researchers.We can design V-based bimetallic electrocatalysts with high catalytic activity by constructing heterostructures,compounding with carbon materials and introducing heteroatoms.Based on the above analysis,the experimental research in this paper contains the following three points:NH₄VO₃and Ni?NO₃?₂were selected as the raw materials to synthesize V-Ni oxide precursors grown on carbon cloth,and the hydrothermal reaction happened in the weak alkaline environment provided by CO?NH₂?₂and NH₄F.Then it was calcined at high temperature in a NH₃atmosphere to obtain a nanospherical VN@Ni₃N-Ni/CC heterojunction.The results show that the V-Ni bimetallic nitride heterojunction synthesized by this method can be used as an efficient catalyst material for hydrogen evolution reaction in a wide p H range.The onset potentials of VN@Ni₃N-Ni/CC were 8,23 and 32 m V and showed excellent stability in 1.0 M KOH,1.0 M PBS and 0.5 M H₂SO₄electrolytes,respectively.Co?NO₃?₂·6H₂O and NH₄VO₃were used as cobalt source and vanadium source,respectively.Nickel foam?NF?was selected as self-supporting material.The neatly arranged nanowire arrays were obtained by a simple hydrothermal reaction.Vanadium-cobalt bimetallic phosphide grown on NF was successfully prepared by low temperature annealing treatment of sodium hypophosphite.The controllable synthesis of bimetallic phosphide was realized by exploring different hydrothermal time and Co/V mole ratio to obtain OER electrocatalyst with excellent catalytic activity.Co VP/NF-4has the best catalytic activity for oxygen evolution reaction.The overpotential is only282 m V when the current density is 10 m A cm^-2,the Tafel slope is 55 m V dec^-1,and Co VP/NF-4 has good stability in 1.0 M KOH solution.Based on the previous researches,it was found that anionic doped bimetallic compounds have great application space in the field of electrocatalytic decomposition of water.Therefore,vanadium-cobalt bimetallic sulfide grown on carbon cloth was prepared and applied to overall water splitting in alkaline electrolytic.A simple hydrothermal reaction was used to obtain the Co-V-O/CC precursor,and the sulphur powder?S?was chosen as a sulfur source and treated peacefully at a temperature of 350^oC to obtain Co VS/CC-4 nanowire arrays.Co VS/CC-4 shows excellent catalytic activity used as cathode and anode in the two electrode systems for electrocatalytic decomposition of water to produce H₂and O₂.Only 1.53 V is required to achieve a current density of 10 m A cm^-2,showing excellent stability in alkaline solution.