Hybridizing amorphous nickel cobalt phosphate and nickel phosphide as an efficient bifunctional nanocatalyst towards overall water splitting

Here a nanohybrid material consisting of amorphous nickel cobalt phosphate loaded on the nickel phosphide foam was designed and synthesized as an outstanding nanocatalyst to catalyze both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline conditions. The high activity of amorphous materials and the great stability as well as the good conductivity of crystalline materials were successfully integrated. The nickel cobalt phosphate was recognized as the active component, while the nickel phosphide was of crucial importance and showed a substrate enhancement effect on the elevated catalytic activity, including the amplification of active surface area and constructing a channel between the electrode and the active sites. Notably, the nanohybrid system can drive the cathodic/anodic current density to be 10 mA cm(-2) with the overpotentials of only 73 mV in HER test and 234 mV in OER test, which outperformed most of the cobalt-based nanocatalysts so far. Finally, a two-electrode configuration with the nanohybrid catalyst as both cathode and anode was established, which required a cell voltage of only 1.55 V to aff ;ord a water splitting current density of 10 mA cm(-2) in 1.0 M KOH.