Novel synthesis of CuHCF/B-rGO composites for oxygen evolution reaction activity

In this work, we have focused on the preparation of copper hexacyanoferrate/boron doped rGO composites (abbreviated as CuHCF/B-rGO) by employing simple co-precipitation technique subsequently processed with ultrasonication method. The XRD spectra confirmed the existence of the cubic structure of copper hexacyanoferrate with high crystalline peaks. The prepared nanocomposite morphology was evaluated by scanning electron microscopy (SEM), and confirmed CuHCF nanoparticles formation with flake-like and wrinkled sheets. Pure CuHCF nanostructures revealed good OER action at 430 mV to obtain 10 mA/cm². The obtained CuHCF product OER activity can be further upgraded by incorporating the electrically conductive boron doped reduced graphene oxide matrix into CuHCF nanostructures, for the reason that the overpotential of the CuHCF/B-rGO was reduced to 380 mV to attain 10 mA/cm² with 88 mV/dec Tafel slope value. The doping of heteroatom considerably improves charge-transfer resistance of metal hexacyanoferrate, giving a small resistance value of 2.97 Ω, which was lower than that of CuHCF (5.57 Ω) and CuHCF/rGO (4.31 Ω). Furthermore, the catalytic activity of the CuHCF/B-rGO was stable at prolonged hours with a small decay of 12.5%. Therefore, this work offers new approach to stimulate the catalytic performance of metal hexcyanoferrate by highly conductive carbon-based materials for water splitting performance.