ABSTRACT This work reports the first investigation of cobalt‐doped Cu 2 MnSnS 4 (CMTS: Co) thin films prepared by sol‐gel dip‐coating, which serve as efficient photocatalysts for both organic pollutant degradation and hydrogen evolution under visible‐light irradiation. Successful incorporation of Co by substitution at Mn sites was corroborated by EDS and XPS analyses, while XRD and Raman analyses verified the retention of the tetragonal stannite structure with Co‐induced lattice distortion. SEM observations further revealed notable microstructural modifications in the CMTS films as a function of Co content. A slight reduction in the optical band gap from 1.92 to 1.79 eV was observed with increasing Co doping. The sample doped with 6 at. % Co achieved a RhB degradation efficiency of approximately 95% within 120 min, mainly driven by · O 2 − radicals, and exhibited a fourfold enhancement in hydrogen evolution activity compared to the undoped counterpart. These improvements are attributed to enhanced charge separation, carrier mobility, and increased active sites. Overall, this work demonstrates a scalable strategy to significantly enhance CMTS photocatalysts, highlighting their strong potential for integrated wastewater treatment and solar hydrogen production.
Adel Chihi (Sun,) studied this question.