Enhanced Adsorption Ability of CoS-Doped CuS for Promoting Electrochemical Oxidation of HMF

In the face of the intensifying energy and environmental challenges, the exploration of clean and sustainable approaches to energy conversion and utilization holds paramount significance. 5-Hydroxymethylfurfural (HMF), as a biomass platform compound with great potential, has drawn extensive attention for its oxidation to prepare 2,5-Furandicarboxylic acid (FDCA). In this study, a CoS-doped CuS composite catalyst (CoS–CuS) was synthesized via a one-step microwave–hydrothermal method for the electrocatalytic oxidation of HMF. The catalyst was comprehensively analyzed by means of multiple characterization techniques and electrochemical testing methods. The results demonstrate that the doping of CoS optimizes the surface electronic structure of the catalyst, enhancing its adsorption capabilities for HMF and OH−. Compared with the CuS catalyst, CoS–CuS in the 5-hydroxymethylfurfural oxidation reaction (HMFOR) shows a lower onset potential decreasing from 1.32 VRHE to 1.29 VRHE. At a potential of 1.4 VRHE, the current density of CoS–CuS attains a value 2.02-fold that of CuS. Significantly, CoS–CuS demonstrates a substantially higher Faraday efficiency in the generation of FDCA, reaching nearly 89.1%. This study provides a promising approach for the construction of other efficient copper-based electrocatalysts.