Fe and Mo Co-modulated Coral-like Nickel Pyrophosphate in-situ Derived from Nickel-Foam for Oxygen Evolution.

Abstract

The highly active catalyst for the oxygen evolution reaction (OER) is critial to achieving high efficiency in hydrogen generation from water splitting. Direct converting nickel foam (NF) into nickel-based catalysts has attracted intensive interest due to the tight interaction of the catalysts to the substrate surface. However, the catalytic performances are still far below expectation because of the problems of low catalyst amount, thin catalyst layer and small active area caused by the method limitation. Herein, we develop a Fe3+-induced synthesis strategy to transform the NF surface into a thicker catalyst layer. In addition to the excellent conductivity and high stability, the as-prepared FeMo-Ni2P2O7/NF catalysts expose more active sites and facilitate mass transfer due to their thicker catalyst layer and highly dense coral-like micro-nano structure. Furthermore, the Mo, Fe co-modulation optimizes the adsorption free energies of the OER intermediates, boosting the catalytic activities. Its catalytic activity is among the highest, and it exhibits a small Tafel slope of 34.71 mV/dec and a low overpotential of 161 mV for delivering current density of 100 mA/cm2 in all of the reported Ni-based catalysts. The present strategy can be further used in other catalysts design for energy storage and conversion.