Metal Doping in 2D Co3O4 for Enhanced ORR/OER Electrocatalytic Performance

Abstract

Spinel cobalt oxide or Co3O4, has been proven to be a promising material as bifunctional electrocatalyst for ORR/OER. In this study, we show further improvement of the electrocatalytic activity via metal doping. Metal-doped Co3O4 was synthesized using a simple hydrothermal method at 120° C for 24 h, followed by calcination at 400° C for 1 h. A surfactant was used to control the morphology of the sample such that either 1D or 2D structure was obtained. The 2D structure shows better electrical conductivity with Rct of 70 Ohm vs. 86 Ohm for the 1D structure. Electrochemical test show that the 2D structure gives a ∆E of 870 mV vs. 949 mV for the 1D structure, due to primarily the excellent ORR activity of the 2D structure, i.e., E-3 = 711 mV for the 2D structure vs. E-3 = 667 mV for the 1D structure. The use of the 2D structure in zinc air battery is also demonstrated.