LAUSR

We report the very first example of a catalyst based on a ternary composite of graphitic carbonitride (g‐C3N4), ceria (CeO2) and magnetite (Fe3O4) for overall water splitting in 1.0 M KOH. Synergy between the components due to electronic effects results in a highly efficient catalyst which catalyzes Oxygen Evolution Reaction (OER) and Hydrogen Evolution Reaction (HER) at substantially low overpotentials (400 mV and 310 mV respectively) to produce benchmark current density (10 mA cm−2). OER activity of the catalysts surpasses that of the benchmark RuO2 catalyst at higher current densities (≥50 mA cm−2). The composite catalyst is stable and shows a Faraday efficiency of 98 % for OER. Overall water splitting was achieved at an overpotential of 1.94 V which is substantially high at 1 wt % loading of active metal.