Microporous nickel phosphonate derived heteroatom doped nickel oxide and nickel phosphide: Efficient electrocatalysts for oxygen evolution reaction

Abstract

Designing low-cost and highly efficient electrocatalysts based on widely abundant elements is highly desirable for future green energy production. Transition metal oxides and phosphides have recently been demonstrated to be promising and cost-effective electrocatalysts due to their distinct surface properties and good conductivity. Herein, we have synthesized a new microporous organic-inorganic hybrid nickel phosphonate (NiPPA) material under hydrothermal reaction condition without the use of structure directing agent. The microporous NiPPA material can be converted to N, P-codoped nickel oxide (NP/NiO) and N, O-codoped nickel phosphide (NO/NiP) following pyrolysis under air and nitrogen atmospheres, respectively. These high surface area materials are subsequently explored as electrocatalysts towards oxygen evolution reaction (OER) in alkaline media. Among the three catalysts, NP/NiO exhibits the highest electrocatalytic activity for OER with an overpotential of 332 mV to reach a current density of 10 mA cm and a low Tafel slope of 65.6 mV dec in 1.0 M KOH solution. Furthermore, the as-prepared NP/NiO catalyst displays an outstanding stability over a period of 15 h, suggesting the high durability of this catalyst for OER