Electrochemical Characteristics of Nanosized Cu, Ni, and Zn Cobaltite Spinel Materials

For a long time, transition metal oxide systems have been considered well explored materials in heterogeneous catalysis. Amongst, the spinel-type oxides, materials such as cobaltites (Co3O4) received significant attention, owing to their use in many industrial applications. In the present study, nanosized Cu, Ni, and Zn cobaltite spinel oxides were synthesized by a simple hydrothermal method. Physicochemical characterization of the synthesized materials was performed utilizing XRD, HRTEM, CO2-TPD, and XPS techniques. The textural characteristics (BET-surface area, pore size, etc.) of samples were determined from N2 physisorption measurements at −196 °C. The CO2-electrocatalytic reduction was selected as a model reaction to evaluate the electrochemical performance of the synthesized spinel cobaltites. For Ni, Cu, and Zn spinel materials, hydrogen was produced as the main product at the whole potential, along with other products, such as CO and HCOOH. Despite the advantages, the catalytic electrochemical CO2 reduction performance of spinel cobaltite catalysts is still far from adequate, which is principally ascribed to the low number of active sites combined with poor electrical conductivity.