A density functional theory study of catalytic oxygen reduction reaction on Co-CoO(111)

Abstract

The demand for clean energy has greatly increased given the current situation of environmental pollution and energy shortages. Fuel cells have attracted much attention because of their high energy density and low pollutant emission. However, the oxygen-reduction reaction (ORR) kinetics of the cathode are slow, and many platinum-based catalysts are needed to drive the reaction. The high platinum price and scarce reserves limit the application of fuel cells. It is therefore urgent to develop cheaper and more efficient non-noble-metal catalysts to drive the ORR. One promising approach is to develop transition-metal-oxide catalysts with high ORR catalytic performance. Here, the structure of CoO was modified, and the surface of partially reduced CoO(111) catalyst [Co-CoO(111)] was simulated via density functional theory (DFT). The catalytic ORR on two kinds of Co (Co-2, Co-3) on the Co-CoO(111) surface were simulated and free-energy diagrams were created. When Co-2 was used as the active site, the Co-CoO(111) catalyst had a low overpotential of 0.34 eV. Besides, when Co-3 site was covered with O and Co-2(*)-Co-3(O*) is used as ORR reaction site, it still had good catalytic performance of ORR. The electronic structure of Co-CoO(111) was used to explain the high level of the ORR.