Cation‐Modified Co‐Based Borophosphates for Efficient and Robust Oxygen Evolution Reaction

Abstract The development of cost‐effective electrocatalysts for oxygen evolution reaction (OER) is critical and challenging in the field of electrocatalytic water splitting for industrial applications. Herein, a series of cations (Fe, Ni, and Zn)‐doped Co‐based borophosphates with an anion skeleton (Na 2 CoB 3 P 2 O 11 (OH)· n H 2 O are prepared by a simple hydrothermal method, in which the cation dopants could be easily achieved via a simple cation exchange during the hydrothermal reaction process. Especially, the Fe dopant increases active sites, improves charge‐mass transfer, and tunes the electronic structures of the Co‐based borophosphate electrode. The optimal Fe‐doped NaCBPO (NaC 3 FBPO), with the cobalt to iron molar ratio of 3, shows a low overpotential of 289 mV at the current density of 10 mA cm −2 , and it can be stable for 16 h at this current density. Above all, it has a fast reaction rate with a low Tafel slope of 84.25 mV·dec −1 . This work provides a promising transition metal‐based borophosphates materials with high efficiency and durability toward water splitting.