High-valance molybdenum doped Co3O4 nanowires: Origin of the superior activity for 5-hydroxymethyl-furfural oxidation

Co3O4 has been widely explored in electrocatalytic 5-hydroxymethyl-furfural (HMF) oxidation. However, the poor intrinsic ability has seriously limited its electrochemical ability. Heteroatom-doping is an efficient method to enhance the electrocatalytic ability of catalyst by regulating electronic structure. Herein, we have modulated the electronic structure of Co3O4 by high valance Mo6+-doping. With the introduction of Mo6+, the content of Co2+ was increased and metal-oxygen bond was strength. Electrochemical results suggested that the electrocatalytic ability of Co3O4 towards HMF oxidation has been dramatically improved and reaction kinetics has been fasten. Theoretical calculations demonstrated that the surrounding cobalt sites after Mo6+-doping with assembled electron has a strong adsorption ability towards HMF molecule leading to more favourable oxidation of HMF. Post characterizations demonstrated pristine Co3O4 structure was kept after electrolysis cycles and CoOOH active species were formed. This work provides a valuable reference for developing efficient heteroatom-doped electrocatalysts for HMF oxidation.