Transformation of Cuprous Oxide into Hollow Copper Sulfide Cubes for Photocatalytic Hydrogen Generation

Copper sulfide (Cu_xS) with a hollow structure derived from the controlled transformation of cuprous oxide (Cu₂O) demonstrated high activity for photocatalytic hydrogen generation with good reproducibility. While the high photocatalytic activity was facilitated by the better crystallinity and lower copper defect density (thus suppressed charge recombination) yielded through the controlled and equilibrated transformation reaction, the stability of the hollow Cu_xS photocatalyst was attributed to its resistance to sintering induced by the chemical dissolution-redeposition of copper (physicochemical stability). Without the controlled synthesis environment, irregularly shaped Cu_xS accompanied by a higher level of copper defects was obtained. During photocatalytic reaction, the irregularly shaped Cu_xS was more susceptible to deactivation through an agglomeration process.