Self-supporting nano array CoP/CP catalysts towards alkaline hydrogen evolution reaction

Developing low-cost and high-performance catalysts for alkaline HER is essential for hydrogen production technologies. Cobalt phosphide (CoP) material has become a candidate material for replacing precious metal catalysts due to its high natural abundance and adjustable electronic structure. However, the inherent structure and limited active sites of cobalt phosphide limit its catalytic performance. Cobalt phosphide (CoP/CP) self-supporting electrodes, grown in-situ on carbon paper (CP), have been prepared using a morphology control strategy. By using surfactant PEG-6000 the morphology of α-Co(OH) 2 precursors, and subsequently the microstructure, crystal structure, surface chemical state and hydrophilicity of CoP are regulated. The self-assembly of CoP nanosheets form a monolayer material with regular staggered arrangement and uniform pore structure. The alkaline hydrogen evolution reaction (HER) tests reveal that the CoP/CP electrode prepared with 0.4 g L −1 PEG-6000 and a phosphorization temperature of 350 °C exhibits excellent electrocatalytic activity in 1.0 M KOH. It needs only a low overpotential of 96 mV to deliver a current density of 10 mA cm −2 , along with a small Tafel slope of 67.0 mV dec −1 . The study provides a new approach for adjusting the performance of cobalt phosphide catalysts.