Realizing favorable synergism towards efficient oxygen evolution reaction with CuO nanoparticles anchored defect engineered graphene

Herein, we demonstrate a P-doped defective reduced graphene oxide (PDrGO), uniformly decorated with CuO nanocrystals (CuO/PDrGO-A) as a high performance noble metal free electrocatalyst for OER in alkaline condition. The composite was synthesized via task specific defect engineering of reduced graphene oxide and doping it with phosphorous (PDrGO), and decorating it with CuO nanocrystals via a reflux method followed by annealing. The formation of the composites (CuO/PDrGO-A) was confirmed via different structural (XRD, XPS, Raman) and morphological characterization (FESEM) techniques. The OER performance was studied in 1 M KOH, which exhibited a considerably low overpotential of CuO/PDrGO-A exhibited a notably low overpotential of 351 mV (100% iR corrected, and 377 mV overpotential for without iR correction) at 10 mA cm⁻², a low Tafel slope of 38 mV dec⁻¹, and enhanced charge transfer kinetics. The catalyst also showed excellent durability with a minimal current decay of 11.5% over a long term chronoamperometric operation over 48 h. The performance was significantly higher than many other previously reported Cu based composites electrocatalyst, revealing a favorable synergism between the PDrGO and CuO towards pushing the performance limits of the existing Cu based OER electrocatalysts.