Electrocatalytic activity of Cu-Co prussian blue analogue and its calcined derivatives towards OER

Abstract

Cu-Co prussian blue analogue (Cu-Co:PBA) was synthesized, mixed with graphite and calcined at 550 °C for 4 h to prepare calcined derivative of Cu-Co:PBA and graphite (G@Cu-Co:PBA©). Also, graphite, Cu-Co:PBA and dopant (sodium hypophosphite, thiourea, melamine and glucose for P, S, N and O doping, respectively) were mixed and calcined at a similar procedure to prepare X-doped calcined derivatives of G@Cu-Co:PBA (X-doped:G@Cu-Co:PBA© where X = P, S, N, and O). Then, different modified carbon paste electrodes (CPEs) were fabricated with the prepared materials and their electrocatalytic activities towards oxygen evolution reaction (OER) were investigated in an alkaline medium. The anodic polarization curves of the modified CPEs were recorded and their corresponding Tafel plots were obtained to calculate their onset potentials, Tafel slopes and η₁₀ (the required overpotential to achieve the anodic current density of 10 mA cm⁻²) as the electrocatalytic performance's criteria to evaluate the effect of calcination and doping on their electrocatalytic activity towards OER. The results revealed that the electrocatalytic performance of CPEs modified with X-doped:G@Cu-Co:PBA© (where X = P, S, N, and O) towards OER improved and their onset potentials and Tafel slopes decreased when CPEs were modified with X-doped in the order O-doped, N-doped, S-doped and P-doped.