New microporous nickel phosphonate derivatives N, P-codoped nickel oxides and N, O-codoped nickel phosphides: Potential electrocatalysts for water oxidation

Abstract

The development of a highly efficient non-noble metal-based electrocatalyst is very challenging for oxygen evolution (OER) reactions. The construction of heteroatom doped transition metal-based phosphonate derivatives such as metal oxides and phosphides are a potential candidate for electrocatalytic OER. Herewith, newly designed microporous organic-inorganic hybrid nickel phosphonate (NiGLy) has been synthesized using N, N-Bis(phosphonomethyl)glycine, and nickel nitrate hexahydrate under simple hydrothermal reaction conditions. The heteroatom doped derivatives, i.e., N, P-codoped nickel oxide (NiO500, NiO700), and N, O-codoped nickel phosphide (NiP500, NiP700), have been obtained by direct pyrolysis of NiGLy at different temperatures under aerobic and inert atmospheres, respectively. Due to the high specific surface area and the presence of micropores, these materials have been explored in the electrocatalytic oxygen evolution reaction. Notably, among other assynthesized electrocatalysts, N, P-codoped nickel oxide (NiO500) exhibits the outstanding electrocatalytic OER activity where the overpotential is found to be 284 mV and Tafel slope is 50.0 mV dec ? 1 in alkaline solution. Also, the as-synthesized NiO500 catalyst shows excellent stability up to 50 h time.