Investigation of Al doped Rh@Cr2O3/SrTiO3 photocatalysts in overall seawater splitting with the synergetic electron mediators

Abstract

Background

The solar-driven photocatalytic seawater splitting process for simultaneous hydrogen and oxygen gas has garnered significant attention as a promising technique for generating eco-friendly chemical fuels. This approach is particularly attractive because of its low cost, and the ability to utilize abundant sunlight and seawater resources.

Methods

The Rh@Cr₂O₃/SrTiO₃:Al (RCSTOA) heterojunction photocatalyst, synthesized via flux technique and photodeposition treatment, possessed distinctive physicochemical properties and exhibited high photocatalytic seawater-splitting performance.

Significant findings

The findings emphasized that the thin layers of Rh@Cr₂O₃ structure (5–20 nm) firmly intimate with a SrTiO₃:Al (STOA) photocatalyst significantly enhanced the seawater-splitting process without requiring any sacrificial agents. Hydrogen and oxygen evolution rates (HER and OER) in natural seawater splitting increased significantly, achieving 263 and 130 µmol.g⁻¹.h⁻¹, respectively maintaining photostability after five consecutive cycles under simulated sunlight illumination. Notably, under the synergy of I⁻-anion solution, the HER improved to 332 µmol.g⁻¹.h⁻¹ without any OER, highlighting potential for H₂/O₂ separation. These findings are expected to advance seawater splitting technology and contribute to potential H₂/O₂ separation techniques in this field.