Abstract

            In this work, we have focused on the preparation of copper hexacyanoferrate/Boron doped rGO composites (abbreviated as CuHCF/B-rGO) by using a simple co-precipitation method followed by the ultrasonication process. The XRD spectra confirm the existence of the cubic structure of copper hexacyanoferrate with high crystalline peaks. The morphology of the nanocomposite was evaluated by scanning electron microscopy (SEM), which revealed the formation of a nanocube structure with flake-like and wrinkled sheets. Pure CuHCF nanostructures exhibited the superb OER activity at 430 mV overpotential to deliver the current density of 10 mA/cm². The OER activity of the CuHCF can be further upgraded by incorporating the electrically conductive boron doped reduced graphene oxide matrix into CuHCF, for the reason that the overpotential of the CuHCF/B-rGO was reduced to 380 mV to deliver the current density of 10 mA/cm² with a Tafel slope value of 88 mV/dec. The doping of heteroatom considerably improves the charge-transfer resistance value 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.

Keywords: Heteroatom dopant, reduced graphene oxide, copper hexacyanoferrate, OER performance.