Copper oxide nanosheets prepared by molten salt method for efficient electrocatalytic oxygen evolution reaction with low catalyst loading

Abstract

In this present study, we report tuning the catalytic activity in heterogeneous copper oxide (CuO) material as an efficient catalyst in 1.0 M KOH for the oxygen evolution reaction (OER) with low catalyst loading. The CuO materials were facilely synthesized by a simple molten salt method at a high temperature and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) surface area analysis. The catalytic water oxidation activity is affected by many factors, such as the catalyst morphologies, electronic double-layer capacitance, and the conductivity. Under optimal conditions, the CuO material prepared at 900 °C showed the nanosheets structure with more exposed catalytic active sites and demonstrated high catalytic performance for OER with a low overpotential of only 420 mV to achieve 10 mA/cm2 and 520 mV to achieve 40 mA/cm2, respectively. Furthermore, when CuO nanosheets are mixed with multi-walled carbon nanotubes (MWCNTs), the catalyst loading can be greatly decreased from 0.7 mg/cm2 to 0.14 mg/cm2 and the overpotential for 40 mA/cm2 is also lowered to 470 mV.