High-efficiency photocatalytic hydrogen production over onion carbon/Mn_0.5Cd_0.5S

In this study, onion carbon-modified Mn_0.5Cd_0.5S (OC/MCS), a novel composite photocatalytic material, was successfully synthesized <i>via</i> a viable hydrothermal process. Techniques such as transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy were employed to comprehensively investigate its morphology, structure and photo-properties. The photocatalytic hydrogen production performance was also measured. The results indicated that the optimal OC/MCS sample achieved a hydrogen production rate of 3582.84 μmol h⁻¹ g⁻¹, which was 6.6 times higher than that of the original MCS. The apparent quantum efficiency at 420 nm was 6.31%. After four times cycling experiments, the photocatalytic performance remained relatively stable. The incorporated OC could serve as electron acceptors, facilitating the separation of holes and electrons in OC/MCS. This not only enhanced the hydrogen production property of the photocatalyst but also ensured excellent stability. Finally, a mechanism for hydrogen production over OC/MCS was proposed.