Ni2P hollow microspheres for electrocatalytic oxygen evolution and reduction reactions

Ni2P hollow microspheres were synthesized and examined as an electrocatalyst for both O-2 evolution and reduction reactions. This hollow microsphere structure, assembled from ultrathin nanosheets, has a high surface-to-volume ratio and is beneficial for fast charge transfer and mass diffusion. This Ni2P material is efficient for water oxidation, achieving a 10 mA cm(-2) current at a 280 mV overpotential. It is also effective in catalyzing the reduction of O-2 with an onset potential of 0.92 V, representing a rare example of Ni phosphides as O-2 reduction catalysts.