Synergistic enhancement of bifunctional electrocatalysis for ORR and OER: Unveiling the role of Cr-doped CoS2 and N-doped carbon

Bifunctional catalysts capable of efficiently and eco-consciously facilitating both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) hold an instrumental role in advancing the commercialization of metal-air batteries. In this study, experiments and Density Functional Theory (DFT) calculations confirm that the doping of Cr into CoS2 can effectively adjust the electronic configuration, thereby improving the catalytic efficiency of ORR and OER. On this basis, Co0.95Cr0.05S2/NC electrocatalyst was synthesized utilizing a low-temperature molten salt method without the conservation of inert atmosphere. The BET analysis indicates a significant increase in the specific surface area of the material due to the composite of Co0.95Cr0.05S2 and nitrogen-doped carbon, augmenting the quantity of active sites available for the reaction. In addition, the Co0.95Cr0.05S2/NC catalyst exhibits an ORR half-wave potential of 0.858 V and an OER overpotential of only 210 mV at a current density of 10 mA cm-2, which is superior to the currently reported related catalysts. Furthermore, DFT calculations confirm that the synergistic effect between Co0.95Cr0.05S2 and NC significantly amplifies the bifunctional catalytic capacity of the electrocatalyst. This study provides new a experimental method and theoretical insight for the design and preparation of excellent bifunctional electrocatalysts.