Combined nano/micro-structure of Ni12P5-Ni2P nanorod array for effective wide pH range HER and overall alkaline water-splitting

Abstract

• A self-supported Ni 12 P 5 -Ni 2 P-NR@NF was fabricated. • The Ni 12 P 5 -Ni 2 P-NR@NF demonstrated excellent HER (ŋ 10 was 107 mV, 138 mV and 168 mV in acidic, neutral and alkaline electrolyte, respectively) and overall water-splitting activity (ŋ 20 = 1.53 V, with stability of ∼120 h) in alkaline media. • The combination of unique structure and intrinsic chemical properties was responsible for the excellent electrocatalysis performance of Ni 12 P 5 -Ni 2 P-NR@NF. A self-supported Ni phosphide nanorod array (Ni 12 P 5 -Ni 2 P-NR@NF) was synthesized using a one-step method to produce a multifunctional electrocatalyst. Benefiting from the unique structure and intrinsic chemical properties, the Ni 12 P 5 -Ni 2 P-NR@NF demonstrated excellent HER activity across a range of pH values and overall water-splitting in alkaline media. To achieve a current density of 10 mA cm −2 , the optimized Ni 12 P 5 -Ni 2 P-NR@NF required an overpotential of 107 mV, 138 mV and 168 mV in acidic, neutral and alkaline electrolyte, respectively. In addition, when used as both anode and cathode for a two-electrode electrolyze to perform water electrolysis in 1.0 M KOH, the cell only needed 1.53 V to achieve 20 mA cm −2 with stability of ∼120 h, providing evidence of multifunctional potential for large-scale applications.