Phosphate Group Dependent Metallic Co(OH)2 toward Hydrogen Evolution in Alkali for the Industrial Current

Developing efficient and low-cost electrocatalysts is critical for hydrogen evolution by water splitting. Nonsubjective reconstruction is one of the main issues that induces difficulty to develop and understand the well-defined structure during the electrocatalysis. By studying the anion-exchange between phosphate and hydroxide, cobalt hydroxide nanosheets incorporated with phosphate inherited from cobalt phosphate are obtained, which provides a new case of metallic transition metal hydroxide. Benefiting from more exposed active sites, effective electron transport, and optimized electronic structure, the residual phosphate in two-dimensional Co(OH)(2) gives rise to significant improvement in alkaline hydrogen evolution. Particularly, it can survive at 1600 mA cm(-2) and maintain stability over 100 h under industrial conditions (6 M KOH at 60 degrees C). Density functional theory calculations and the confirmatory experiments of reverse anion-exchange from Co(OH)(2) are investigated to confirm the successful engineering of metallic character and electronic structure. This work provides a facile modification of practical electrodes with phosphate groups for industrial water electrolysis as well as gaining insights into the reconstruction of cobalt-based electrocatalysts in alkali to become an effective catalyst.

Automated summary

Developing efficient and low-cost electrocatalysts for hydrogen evolution through water splitting is crucial. In this study, it was discovered that anion-exchange between phosphate and hydroxide can lead to cobalt hydroxide nanosheets incorporated with phosphate, which greatly improves the alkaline hydrogen evolution efficiency and stability. This research has important implications for industrial water electrolysis and the design of improved electrocatalysts.