Vertically aligned NiP2 nanosheets with interlaced mesh network for highly efficient water splitting under alkaline and acid solutions

Abstract

Chemically polished Ti foil has been shown to be an excellent substrate for the growth of low-interface-resistance electrocatalysts. Herein, we grow vertically aligned interlaced-mesh-network NiP2 nanosheets on deeply polished Ti foil (NiP2 NS/Ti) by the gas-phase phosphidation of Ni(OH)2. The produced interconnected nanosheets provide abundant electron transfer pathways and facilitate electron transfer, as confirmed by electrochemical impedance spectroscopy measurements and the presence of numerous voids that allow for fast gas release and ion migration. In view of the above advantages, the NiP2 NS/Ti shows high electrocatalytic activity for the hydrogen evolution reaction in both alkaline and acidic solutions, wherein overpotentials of only 134 and 140 mV are required to attain a current density of 10 mA cm−2, respectively. In addition, the above electrode also features a small Tafel slope (60.5 mV dec−1 in alkaline and 49.5 mV dec−1 in acidic solutions) and long-term stability, and can therefore be employed as an efficient and cheap three-dimensional cathode for electrochemical water splitting.