Laser-Induced One-Pot Deposition of Medium-Entropy Cocatalysts on Hematite Thin Films for Improved Photoelectrochemical Water Splitting

In this study, we integrate medium-entropy cocatalysts (MECs), composed of four elements─Fe, Ni, Co, and Cr─into nanostructured hematite (Fe 2 O 3 ) thin films using a laser deposition process to enhance the photoelectrochemical (PEC) water splitting performance. The MEC-integrated hematite (MEC-Fe 2 O 3 ) photoanodes exhibit remarkable improvements in water oxidation photocurrent, achieved through enhanced charge injection efficiency and a negatively shifted onset potential compared to bare Fe 2 O 3 . Multiphysics modeling elucidates the laser-induced MEC formation mechanism by estimating the temperature increase and changes in energy band structure and carrier concentrations. Furthermore, time-resolved photoluminescence (TRPL) studies unveil that the MEC layer extends the carrier lifetime of photogenerated charge carriers, leading to an overall enhancement in the efficiency of the water oxidation process. This work highlights the promising potential of laser-deposited MEC as a viable strategy to boost the efficiency of hematite photoanodes in PEC water splitting applications.