Enhancing the Kinetics of Glucose Electro-Oxidation by Modulating the Binding Energy of Hydroxyl on Cobalt-Based Catalysts

Abstract

Replacing the sluggish anodic water oxidation reaction with the glucose oxidation reaction (GOR) offers an energy-saving strategy to obtain value-added products during the hydrogen production process. However, rational design of the GOR electrocatalyst with an explicit structure–property relationship remains a challenge. In this study, by using cobalt chalcogenides as model catalysts, we performed an in-depth study of the GOR catalytic mechanism of CoS and CoSe nanosheets. Experimental and theoretical results revealed that the reaction pathway on cobalt chalcogenides strongly depends on their binding energy to hydroxyl (OHBE). For CoS with a weak OHBE, the reaction proceeds through an “electrophilic oxygen” route. While for CoSe, due to the strong OHBE, a surface reconstruction occurs before the GOR and therefore follows the “electrochemical-chemical” route. Inspired by these findings, a customized strategy was proposed to regulate the OHBE of the catalysts, which involved introducing F atoms into CoS to enhance its OHBE, and weakening the OHBE of CoSe by doping with Zn atoms. The optimized F-doped CoS and Zn-doped CoSe catalysts both exhibited significantly improved performance for GOR. This study thus provides a verifiable paradigm for improving the GOR performance via a customized strategy and sheds light on the design of novel catalysts in the future.