Simultaneously Efficient Solar Light Harvesting and Charge Transfer of Hollow Octahedral Cu2S/CdS p–n Heterostructures for Remarkable Photocatalytic Hydrogen Generation

Solar-driven water splitting is a promising alternative to industrial hydrogen production. This study reports an elaborate design and synthesis of the integration of cadmium sulfide (CdS) quantum dots and cuprous sulfide (Cu2S) nanosheets as three-dimensional (3D) hollow octahedral Cu2S/CdS p–n heterostructured architectures by a versatile template and one-pot sulfidation strategy. 3D hierarchical hollow nanostructures can strengthen multiple reflections of solar light and provide a large specific surface area and abundant reaction sites for photocatalytic water splitting. Owing to the construction of the p–n heterostructure as an ideal catalytic model with highly matched band alignment at Cu2S/CdS interfaces, the emerging internal electric field can facilitate the space separation and transfer of photoexcited charges between CdS and Cu2S and also enhance charge dynamics and prolong charge lifetimes. Notably, the unique hollow Cu2S/CdS architectures deliver a largely enhanced visible-light-driven hydrogen generation rate of 4.76 mmol/(g·h), which is nearly 8.5 and 476 times larger than that of pristine CdS and Cu2S catalysts, respectively. This work not only paves the way for the rational design and fabrication of hollow photocatalysts but also clarifies the crucial role of unique heterostructure in photocatalysis for solar energy conversion.