Modulation of crystal water in cobalt phosphate for promoted water oxidation

Herein, low-dimensional cobalt phosphate (Co-Pi) catalysts with variable contents of crystal water were fabricated for oxygen evolution reaction (OER). Owing to the optimized electronic structure, rich surface sites and favorable charge transport ability, Co-Pi tetrahydrate exhibits remarkable OER activity with a low overpotential, large current density and high intrinsic activity, and it is proved to be the optimal Co-Pi phase for OER.