Carbon layer confined Co–Ni bimetallic oxide heterojunctions for high-efficiency electrosynthesis of 2,5-furandicarboxylic acid

Abstract

Electrooxidation of 5-hydroxymethylfurfural (HMF) has been recognized as an efficient method for obtaining high value-added chemicals, so it is desirable to develop highly active and stable catalysts for the electrocatalytic HMF oxidation reaction (HMFOR). In this study, carbon layer confined Co₃O₄–NiO heterojunctions (Co₃O₄–NiO@C) are proposed as the catalysts for high-efficiency electrosynthesis of 2,5-furandicarboxylic acid (FDCA) through the HMFOR. The catalytic current density of Co₃O₄–NiO@C for the HMFOR at 1.4 V is 2.24-fold that of Co₃O₄@C and 2.21-fold that of NiO@C due to the formation of Co–Ni bimetallic oxide heterojunctions. The Co₃O₄–NiO@C catalyst shows high HMF conversion (99.1%), high FDCA yield (99.1%), high Faraday efficiency (98.9%), and high stability. Experimental studies and theoretical calculations demonstrate that the formation of Co₃O₄–NiO heterointerface regulates the electronic structure of the catalyst, promotes OH⁻ and HMF adsorption on the catalyst surface, increases the electronic interactions between the catalyst and HMF, and reduces the energy barrier for FDCA electrosynthesis, resulting in an excellent FDCA electrosynthesis performance. This work elucidates the mechanism of catalytic activity enhancement at heterointerfaces and provides constructive guidance for designing highly active and stable multicomponent electrocatalysts by interface engineering.