Synthesis And Application Performance Of Hydrogen Evolution Electrode Materials In Chlor-alkali Industrial Electrolysis Cell

The chlor-alkali industry is the most basic chemical industrial process,and it has similarities with the current frontiers of electrolysis of seawater to produce hydrogen.Electrolytic water evolution reaction is carried out in a weak acid or weakly alkaline electrolyte.The electrolysis process in the chlor-alkali industry is carried out in a high concentration lye.Therefore,it is necessary to find a material which can perform well in high-concentration electrolyte.In recent years,nickel phosphide has become a research hotspot as a semiconductor electrode material.This thesis studies the preparation of nickel phosphide,especially high index surface phosphide nickel electrode materials.Based on the self-supporting electrode,a high-index surface phosphide was prepared by a simple phosphating,and the structure-activity relationship of the electrolyzed water process was systematically investigated.（1）Self-supporting nickel phosphide electrode materials were synthesized by vapor deposition method,and the effects of synthesis conditions on the synthesized products were investigated in detail.The experimental results show that the high-index surface Ni₅P₄electrode material can be prepared by using red phosphorus as phosphorus source at 500°C,which has high specific surface area and unique morphology.Compared with the Ni₂P electrode material prepared by using sodium hypophosphite as the phosphorus source,the high index surface Ni₅P₄exhibits superior electrolysis hydrogen evolution performance due to its high index surface,and its initial overpotential in 1mol?dm^-3alkali solution is only 30m V.The use of red phosphorus as a phosphorus source can produce a high-index surface Ni₅P₄electrode material with stable performance,which has high application value.（2）The high-index surface sulfur phosphide electrode material was synthesized by combining vapor deposition method and hydrothermal method,and the influence of sulfur dosage was investigated.The experimental results show that the high-index surface Ni₅P₄|S electrode material has improved hydrogen evolution performance after being doped into the sulfur atom,and has high activity in both acid and lye,and has high stability.Theoretical calculations show that the high-index crystal plane has high surface energy;after doping the sulfur atom,the adsorption Gibbs free energy(?G_H*)of the hydrogen ion on the surface of Ni₅P₄|S is higher,so that the adsorption and desorption ability of hydrogen atoms on the electrode surface is balanced.（3）A cationically modified nickel phosphide electrode material was prepared by using a vapor deposition method to incorporate a second metal element into the metal source.The hydrogen evolution performance of the electrolyzed water in a high concentration lye was investigated in detail.The experimental results show that the introduction of a small amount of iron can significantly improve the hydrogen evolution performance of electrolytic water.