Heterogeneous Ni-Boride/Phosphide Anchored Amorphous B-C Layer for Overall Water Electrocatalysis

The rational design of efficient and economical bifunctional electrocatalysts remained a challenge for overall water electrolysis. In this work, the Ni-boride/ phosphide particles anchored amorphous B-doped carbon layer with hierarchical porous characteristics in Ni foam (Ni₃P/Ni₃B/B-C/NF) was fabricated for overall water splitting. The Boroncarbide (B₄C) power was filled and fixed in the NF interspace through the electroplating and electroless plating, and then annealed in vacuum high temperature. The amorphous B-C layer derived from the B4 C not only speeded up the electron transport, but also cooperate with Ni-boride/phosphide to enhance the electrocatalytic activity for HER and OER synergistically. Furthermore, the hierarchical porous architecture of Ni₃P/Ni₃B/B-C/NF increased space utilization to load more active materials. The self-supported Ni₃P/Ni₃B/B-C/NF electrode possessed a low overpotential of 212 and 280 mV to deliver 100 mA cm^-2 for HER and OER, respectively, and high stability for 48 h. In particular, the electrolyzer constituted with the Ni₃P/Ni₃B/B-C/NF bifunctional electrocatalyst only required a voltage of 1.59 V at 50 mA cm^-2 for water electrocatalysis under alkaline medium, and demonstrated long-term stability for 48 h. This study provides a new technical path for the development of bifunctional of transition metal borides to promote the application of hydrogen production from water splitting.