Facile one-step solid-state synthesis of CuO nanoparticles finely decorated over carbon sheets for improved OER activity

Renewable energy storage and conversion in electrochemical fuel cells require highly efficient and cost-effective noble metal free electrocatalysts for oxygen evolution reaction (OER). Downscaling of a material to nanoscale morphology can lead to enhancement in its surface activities affecting its physical and chemical properties which can well serve the purpose. In lieu to this, it could be one of the first reports to tune the morphology of CuO particles to 10-25 nm finely trapped inside non-graphitic carbon sheets using a novel single step solid state reaction. XRD, SEM, TEM, XPS, and Raman analyses confirm the structural and morphological attributes. The synergistic effect from carbon and copper oxide resulted in the attainment of best-in-class electrode material for oxygen evolution reaction (OER). The as-prepared CuO/C shows an excellent OER activity with a low overpotential of 454 mV (vs. Ag/AgCl) at a current density of 10 mA cm-2 with a low Tafel slope of 74.9 mV dec-1. The amount of carbon is optimized to get optimal performance from the CuO nanopowder.