Spinel-Structured photoelectrodes for photoelectrochemical energy and environmental applications: synergistic photothermal-magnetic effects

Abstract

Spinel-structured catalysts have emerged as promising multifunctional materials for sustainable energy conversion and environmental remediation due to their unique electronic configurations, structural flexibility, and magnetic responsiveness. Although spinel-structured catalysts have been summarized in reviews for photocatalytic and electrocatalytic systems, their emerging role in photoelectrochemical (PEC) energy and environmental applications have yet to be comprehensively reviewed. Also, the synergistic PEC systems of spinel electrodes in the presence of photothermal and magnetic fields have not been discussed in depth. This review bridges this gap by systematically analyzing spinel-based materials for PEC water splitting, CO2 reduction reaction (CRR), oxygen reduction reaction (ORR), nitrogen reduction reaction (NRR), and pollutant degradation. Notably, cutting-edge strategies leveraging photothermal and magnetic fields-individually or cooperatively-are highlighted for enhancing PEC efficiency and stability. The photothermal field utilizes localized heating for bandgap modulation to accelerate carrier separation and improve surface reaction efficiency, and the magnetic field utilizes negative magnetoresistance effect, Lorentzian magnetism, and spin polarization to achieve carrier dynamics modulation, thereby addressing critical bottlenecks in PEC energy conversion and environmental remediation. By correlating material design with performance metrics, this work provides critical insights into developing next-generation smart spinel catalysts capable of harnessing solar, thermal, and magnetic energy synergistically. Such innovations pave the way for sustainable energy-environment systems, aligning with global decarbonization goals.