Sodium–cobalt pyrophosphate electrocatalyst for water splitting

Water splitting, an assuring concept for future sustainable hydrogen/oxygen production, is intensely dependent on the efficiency of catalysts to promote the oxygen evolution reaction (OER) or hydrogen evolution reaction (HER). In this regard, finding high-performance electrocatalysts for OER remains amongst the key challenges in water splitting. Here, for the first time, an aerosol-assisted spray pyrolysis method was applied to synthesize hollow spherical powder possessing nano-thick walls of sodium-cobalt pyrophosphate (Na 2 CoP 2 O 7 ) electrocatalyst for OER application. X-ray diffraction (XRD) patterns, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS) analyses were carried out for investigating the structure, composition , and morphology of the electrocatalyst powder. The electrocatalytic performances of the as-synthesized Na 2 CoP 2 O 7 powder along with its composites with Vulcan XC-72 (conductive carbon black), reduced graphene oxide (rGO) and N-doped rGO (N-rGO) were studied by the linear sweep and cyclic voltammetry (LSV and CV). The best sample synthesized was Na 2 CoP 2 O 7 /rGO (50/50 ​wt%), which required only 240 ​mV overpotential to produce a current density of 10 ​mA ​cm −2 .