Photocatalytic hydrogen energy recovery from sulfide-containing wastewater using thiol-UiO-66 modified Mn0.5Cd0.5S nanocomposites

Abstract

The worldwide environmental pollution and energy crisis have become two main challenges currently. To this end, we aim to build a win–win strategy of clean hydrogen energy recovery with simultaneous environmental detoxification by treating sulfide-containing wastewater in a non-hazardous manner. In this study, we designed a heterostructure photocatalyst with in situ growth of MnCdS nanoparticles on thiol-functionalized UiO-66-based materials (UiOS-MCS). A series of characterization analyses showed that UiOS-MCS nanocomposites held favorable properties of efficient charge separation and migration, which thanked to well-matched band structure and tight interfacial contacts via thiol-linked bonds that greatly facilitated the transfer of photogenerated charge carriers. The optimal nanocomposite of 0.5UiOS-MCS exhibited excellent photocatalytic activity under visible light irradiation, with an impressive hydrogen evolution of 3179.36 μmol g−1 h−1 and a significant removal of sulfide contaminants in the wastewater of about 90%, selectively generating valuable oxidation product of monomeric sulfur. The mechanism analysis demonstrated that the main photoactive species required for hydrogen production by photoreduction (electrons) and sulfide removal by photooxidation (holes) were independent of each other, and that the electron-hole division of collaboration ensured an efficient and synergistic redox reaction. This work offers a promising strategy for the recovery of energy stored in wastewater and environmental remediation.