The effect of P vacancies on the activity of cobalt phosphide nanorods as oxygen evolution electrocatalyst in alkali

Anion defects have been utilized to regulate the active sites in the electrocatalytic. Herein, we report a simple NaBH4 reduction tactic to design a novel CoP nanorods electrocatalyst with phosphorus vacancy (Pv) and discuss the effect of Pv content on its oxygen evolution reaction (OER) performance. It is proved that phosphate formed by filling Pv with oxygen is the key factor affecting the activity of catalyst. CoP with appropriate quantity Pvs have excellent OER activity, including lower overpotential (297 mV at 10 mA cm−2), excellent cyclicity (almost no change after 1000 cycles), good stability (small decay after 11 h) and a lower Tafel slope (58.1 mV dec-1). The excessive Pvs will hinder the formation of phosphate, thus affecting CoOx(OH)y active center production and ultimately reducing the OER performance of the catalyst. This study offers a valuable insight to design OER catalysts with anion vacancy defects.