One-Pot Combustion Synthesis of S-Scheme Heterostructured CdS/CdMoO₄ Nanoparticles with Tightly Bound Interface for Enhanced Photocatalytic H₂O₂ Production

In this work, a series of CdS/CdMoO4 samples were fabricated using a simple one-pot combustion method. The crystal structure, morphologies, chemical compositions, and optical properties were characterized through XRD, SEM, TEM, XPS, and UV–vis spectra. The photocatalytic test showed that CdS/CdMoO4 composites had the best H2O2 production performance, achieving a rate of 1394.71 μmol/g/h, which is approximately 2.5 times and 12 times higher than that of pure CdS and CdMoO4, respectively. The significantly improved photocatalytic efficiency can be ascribed to the formation of an S-scheme heterojunction between CdS and CdMoO4. This heterojunction facilitates the efficient separation of charge carriers, thereby inducing high activity for H2O2 formation. Active species trapping experiments revealed that holes (h+) and superoxide radicals (·O2–) were the primary active species involved in the photocatalytic process. Based on the energy band structures of the CdS/CdMoO4 composites, a possible photocatalytic mechanism was proposed.