Design, Synthesis And Electrocatalytic Hydrogen Evolution Performance Of Nitrogen/molybdenum Carbide-based Nanomaterials

Due to the limited reserves and rapid consumption of fossil energy,the demand for energy has become a major challenge for the sustainable development of society.Among all chemical fuels,hydrogen energy has attracted great attention as a substitute for fossil fuels.In addition,electricity chemically splitting water has been considered one of the cleanest methods for hydrogen production.The precious metal platinum(Pt)is identified as the most advanced electrocatalyst for hydrogen evolution reaction(HER),however its low abundance and high price hinder its large-scale production and application.Therefore,it is very significant for mankind to develop high-performance platinum-free electrocatalysts.Molybdenum-based transition metals have attracted great attention from researchers.Typical representatives of molybdenum-based transition metal compounds include:molybdenum nitride(Mo N),molybdenum carbide(Mo₂C)and other materials,which are all promising electrocatalytic materials.Among them,molybdenum nitride(Mo N)has electrons similar to noble metals.Structure,high conductivity and excellent corrosion resistance;as far as molybdenum carbide(Mo₂C)is concerned,this material not only has a d-band electronic structure similar to Pt,but also has attracted special attention for its excellent catalytic stability and low cost.Based on this,this article carried out the following research on molybdenum-based transition metal nitride and carbide materials.In this paper,electrospinning technology,organic-inorganic hybrid method,and electrocatalysts are used for synthesis.The above synthesis strategy can be extended to other catalysts of the same type,and can be better designed for water decomposition with high activity and high durability.The electrocatalyst provides new insights:1.Using electrospinning technology,polymer solution as carrier,adding molybdenum salt,nickel salt and ruthenium salt at the same time,to synthesize nanofiber materials,and then using low-temperature calcination treatment to successfully prepare Ru-Ni@Mo N NFs electrocatalyst.Nanofiber materials have a large electrocatalytic activity area,which is conducive to electron and mass transfer;the addition of Ni salt can effectively adjust the surface charge state of Mo N,realize electron redistribution,and enhance the dissociation ability of Mo N,while also adjusting the binding energy of the HER intermediate;the incorporation of Ru and the synergistic effect between Ni and Mo N make the catalyst have high catalytic activity and catalytic stability in both acidic and alkaline solutions,and can further improve the HER of the material.The performance makes this material reach current density of 10 m A/cm²and 100 m A/cm²in 1 M KOH solution,which requires 33 m V and 152m V overpotentials,respectively,and in 0.5 M H₂SO₄,it reaches 10 m A/cm²and 100m A/cm².The current density of m A/cm²requires overpotentials of 55 m V and 160 m V,respectively.After 100 h of continuous testing under acidic and alkaline conditions,the performance still has no significant decline.2.Using molybdenum salt,cobalt salt and aniline as raw materials,the nanorod precursor was obtained by the organic-inorganic hybrid method,and then calcined in an argon atmosphere by the temperature-programmed method,and the Co O-Mo₂C electrocatalyst was successfully prepared.The electrocatalytic performance of the catalyst is much higher than that of the single-phase Mo₂C catalyst under alkaline conditions.The excellent performance is attributed to the incorporation of metal Co which optimizes the electronic structure of Mo₂C while reducing the charge transfer resistance.The material has an overpotential of 100 m V when the current density reaches 10 m A/cm²,a lower Tafel slope,and a higher catalytic activity.