Localized photothermal heating of phosphate-incorporated iron oxide nanosheets enables greatly enhanced water splitting electrocatalysis

Introducing an external energy field into water electrolysis is considered as an innovative strategy to improve electrocatalysis for water splitting. However, rationally modulating these external energy fields to synergize electrocatalytic processes remains a great challenge. Herein, phosphate-incorporated iron oxide nanosheet arrays (P-FeOx/IF) are constructed as multifunctional photothermal-electrocatalytic electrodes for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). The as-prepared P-FeOx/IF exhibits excellent photothermal conversion performance and enables in-situ surface self-heating under near-infrared (NIR) light irradiation, resulting in a gradual increase in local temperature on the electrode surface. Impressively, the photothermal P-FeOx/IF electrode exposed to NIR light irradiation shows significantly improved electrocatalytic performances with relatively low overpotentials for OER (η10: 280 mV) and HER (η10: 104 mV) to deliver a current density of 10 mA cm−2. Furthermore, a two-electrode system using photothermal P-FeOx/IF as anode achieves a low cell voltage of 1.685 V. This study provides a new avenue for developing high-performance electrocatalysts incorporating photothermal effects.