Amorphous Ni-P with hollow dendritic architecture as bifunctional electrocatalyst for overall water splitting

Abstract

Amorphous Ni-P with elaborate hollow dendritic architecture is fabricated using Morph butterfly-wing scales as template by electroless deposition method. The electrocatalytic performance for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is characterized in alkaline solution. As an anode material, the catalyst shows excellent OER catalytic activity with a low Tafel slope of 67.3 mV dec−1 and a low overpotential of 303 mV to reach 20 mA cm−2, which is comparable to RuO2. As a cathode material, the as prepared Ni-P shows relatively good catalytic performance for HER with a moderate Tafel slope of 75.2 mV dec−1 and an overpotential of −176 mV to deliver 20 mA cm−2. Employing the bifunctional catalyst as anode and cathode material in a two electrode system, a cell voltage of 1.63 V is required to reach an overall water splitting current density of 10 mA cm−2 with good electrochemical stability. The excellent performance should be attributed to the coupling effect of the Ni-P composition with amorphous and P compositing feature and the hollow dendritic architecture with high accessible surface area.