Photothermal enhanced bifunctional catalyst for overall water splitting with phosphide heterojunction FeP-CoMoP.

The development of cost-effective bifunctional electrocatalysts remains a great challenge. In this work, high-performance FeP-CoMoP/NF catalysts were prepared using the strategy of constructing phosphide heterostructures with localized photothermal effect. At 10 mA·cm, the HER overpotential of FeP-CoMoP/NF is 30.8 mV and the OER overpotential is 180.9 mV. Compared to FeP/NF and CoMoP/NF, the higher content of oxygen vacancies in the phosphorylated heterostructure FeP-CoMoP/NF has the potential to enhance intrinsic activity and improve the photothermal effect. With the assistance of localized photothermal effect, the HER (η = 72.7 mV) and OER (η = 252.3 mV) overpotentials of FeP-CoMoP/NF decreased by 35.8 % and 9.9 %, which were more significant than those of CoMoP/NF and FeP/NF. Meanwhile, the FeP-CoMoP/NF catalyst has excellent stability, maintaining 96 % at -500 mA·cm and 94 % at 300 mA·cm after 100 h. In addition, overall water splitting can be carried out using solar panels with a voltage of 1.42 V, which shows its potential for application in combination with sustainable energy sources.