In-situ upcycling of cadmium from wastewater into core-shell ZnS@Zn0.58Cd0.42S heterojunction photocatalyst for environmental purification and H2 evolution

Uncontrolled exploitation of heavy metals has caused environmental pollution and mineral resource depletion crises. The first-choice approach for addressing these issues is heavy metal upcycling. However, efficient retrieval and conversion of heavy metals from contaminated environments into high-value-added products remains challenging. Here, we developed a strategy to simultaneously achieve efficient accumulation (256 mg/g), magnetic separation (similar to 1 min), and directly in-site conversion of Cd2+ from wastewater into core-shell ZnS@Zn0.58Cd0.42S heterojunction photocatalysts (ZSC). Microalgae-derived yolk-shell microspheres containing multicomponent nanocores (Fe3O4 and ZnS) were developed to serve as adsorbent, magnetic carrier, and pho-tocatalyst assembly platform to achieve Cd2+ upcycling into ZSC. In particularly, ZSC shows much higher photocatalytic activity for H-2 generation and organic pollutant degradation than do commercial photocatalysts (P25-TiO2 and CdS) due to its greater utilization of solar energy and heterostructure. Altogether, we provide an appealing strategy for upcycling cadmium into high-performance heterojunction photocatalysts for environ-mental purification and clean energy generation.