Laser-Ablation-Produced Cobalt Nickel Phosphate with High-Valence Nickel Ions as an Active Catalyst for the Oxygen Evolution Reaction

Cost-effective, highly efficient and stable non-noble metal-based catalysts for the oxygen evolution reaction (OER) are very crucial for energy storage and conversion. Here, an amorphous cobalt nickel phosphate (CoNiPO₄ ), containing a considerable amount of high-valence Ni³⁺ species as an efficient electrocatalyst for OER in alkaline solution, is reported. The catalyst was converted from Co-doped Ni₂ P through pulsed laser ablation in liquid (PLAL) and exhibits a large specific surface area of 162.5 m² g^-1 and a low overpotential of 238 mV at 10 mA cm^-2 with a Tafel slope of 46 mV dec^-1 , which is much lower than those of commercial RuO₂ and IrO₂ . This work demonstrates that PLAL is a powerful technology for generating amorphous CoNiPO₄ with high-valence Ni³⁺ , thus paving a new way towards highly effective OER catalysts.