Mn-Doped CoFeP Nanosheets as Effective Electrocatalysts for Superior Overall Water Splitting

For green hydrogen, the exploitation of advanced electrocatalysts is crucial, and transition metal phosphides have great potential in water splitting due to their abundant reserves and optimized electronic structure. Herein, a synergistic approach involving Mn doping and phosphorization is applied to CoFe-layered double hydroxide nanoflowers to produce a series of bifunctional catalysts Mn-doped CoFeP (Mn-CoFeP). Electrochemical evaluations demonstrate that the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) performance of Mn(10%)-CoFeP both have notable improvement in 1 M KOH, with the overpotentials of only 160 and 239 mV to achieve current densities of 10 and 100 mA cm⁻², respectively. Comparative electrocatalytic analysis indicates that moderate Mn doping mainly contributes to improve the OER performance, while the phosphorization significantly enhances the HER activity, resulting in effective bifunctional catalysis. For overall water decomposition, a total hydrolysis electrolysis cell equipped with the Mn(10%)-CoFeP bifunctional catalyst requires only 1.64 V to reach a current density of 10 mA cm⁻². Furthermore, it performs stable operation for 10 h at a current density of 10 mA cm⁻² with a current maintenance rate of 83.6%. This work offers new insights into preparing effective bifunctional electrocatalysts, advancing clean energy development.