Application of rare-earth high entropy boride in electrocatalytic hydrogen evolution reaction

Abstract

The preparation of simple, and low-cost and efficient catalysts is essential and challenging for achieving large-scale water electrolysis for hydrogen production. Three new electrocatalysts with high-entropy borides were synthesized by the short-process molten salt-assisted boron thermal reduction method. This paper has discussed the influence of synthesis conditions and rare-earth species on the catalyst performance. At 1 M KOH solution, WMoVNbCeB has the best electrochemical hydrogen evolution activity when the salt-to-material ratio and sintering temperature are 15:1 and 1000 °C, respectively The overpotential of the current density of 10 mA∙cm−2 is as low as 117 mV, the Tafel slope is 111 mV∙dec−1, and it has a large active area. The calculation results show that the combination of the electron orbit of the outer layer of each element promotes the hydrogen evolution reaction. The synergy between the f-orbit of the rare-earth metal and the d-orbit of other transition metals accelerates the charge transfer, and promotes the dissociation of the adsorbent, and then reduces the reaction energy barrier of the hydrogen precipitation process. It is confirmed that the rare-earth high entropy boride has a positive electrochemical activity. This provides a new way and new materials for industrial hydrogen production and has broad guidance and development prospects.