Vanadium-modulated hierarchical Ni2P/Ni12P5 as an efficient heterostructure electrocatalyst for large-current-density hydrogen evolution

Seawater splitting in alkaline media emerges an ideal alternative to conventional freshwater electrolysis by fully utilizing natural resources for sustainable and scalable production of green hydrogen. Exploiting the efficient and robust seawater electrocatalyst towards large-current-density hydrogen production is urgently rewarding, but challenges remain. Herein, a free-standing hierarchical vanadium-doped Ni2P/Ni12P5 heterostructure nanoflower array grown in-situ on nickel foam (V-Ni2P/Ni12P5/NF) is successfully fabricated via calcination protocol by phosphorization of the NiV-LDH precursor in Ar/H2 protective atmosphere. Profiting from the unique hierarchical structure, enhanced electrical conductivity and optimized electronic configuration, the integrated V-Ni2P/Ni12P5/NF heterogeneous electrocatalyst presents highly active and stably electrocatalytic performance for hydrogen evolution. As expected, the as-obtained V-Ni2P/Ni12P5/NF delivers overpotentials of 211/215 mV, 293/306 mV and 334/355 mV in alkaline/alkaline simulated seawater media at high current densities of 100, 500 and 1000 mA/cm2 respectively, accompanying with a remarkable catalytic durability for at least 40 h of consecutive electrolysis in both conditions. This work provides a new insight to construct highly efficient electrocatalysts for alkaline water/seawater towards large-scale hydrogen evolution.