Multiple Interface Ni(PO₃)₂-CoP₄/CoMoO₄ Nanorods for Highly Efficient Hydrogen Evolution in Alkaline Water/Seawater Electrolysis

Abstract

The key to the development of non-noble metal catalysts with high activity and durability for the hydrogen evolution reaction (HER) in alkaline water/seawater conditions is to construct multi-interface electrocatalysts. Herein, the CoMoO4 nanorod arrays grown on foam nickel (NF) was first prepared by a hydrothermal method. Then, Ni(PO3)2-CoP4 with multi-interface was prepared by soaking the nanorod arrays into a nickel nitrate solution and then by phosphating via chemical vapor deposition. The Ni(PO3)2-CoP4/CoMoO4/NF electrode exhibits superior HER electrocatalytic performance under alkaline conditions with an ultralow overpotential of 79 mV@100 mA·cm–2, which outperforms other reported earth–abundant transition-metal phosphide catalysts. It also maintains long-term durability in alkaline water/seawater electrolytes in 60 h at a constant 100 mA·cm–2. In the alkaline natural seawater electrolyte, Ni(PO3)2-CoP4/CoMoO4/NF (−)||NiFe LDH (+) pair has good long-term stability of 60 h for the voltage of only 1.60 V@100 mA·cm–2. The excellent performance is attributed to the plentiful active sites and the rapid electron-transfer rate. This work affords a new path to rationalize the design strategy of low-cost and multi-interface 3D catalysts for alkaline water/seawater electrolysis.