Bioinspired notched volvox-like nested Z-scheme heterostructure improves solar-energy utilization for high visible-light-driven hydrogen production

Natural photosynthetic biosystems, with elaborate spatial structures, possess substantial specific surface areas and strong light-scattering abilities and provide a blueprint for the fabrication of photocatalysts for efficiently capturing and utilizing solar energy. However, mimicking sophisticated natural structures by a rational design is a great challenge. Herein, we report a facile and universal symbiosis hydrothermal synthesis strategy for obtaining biomimetic volvox-like double-core nested hollow materials. The nested hollow materials possessed the special notched "mother-twin" core-shell structure and the core numbers could be well controlled by adjusting the amount of precursor. The notched double-core hollow ZnO/CdS (mother-twin HZC) was facilely constructed by the direct chemical deposition of CdS nanosheets on the double-core hollow ZnO (mother-twin HZ). The notched complex spatial heterostructure possessed a multiple light-reflection capability (improving the utilization of solar energy), tight interfacial contact (favoring charge migration), and a high surface-to-volume ratio (providing sufficient active sites for H2 production). Both the Z-scheme ZnO/CdS heterostructures and the special nested hollow structure could synergistically enable achieving a remarkable hydrogen generation rate (up to 18.70 mmol g-1 h-1) under visible-light irradiation, exceeding that of the reported similar ZnO/CdS heterostructure without co-catalysts. Bioinspired by the nested structure of volvox with multi-subcell, a facile and universal symbiosis hydrothermal strategy is reported to synthesize volvox-like double-core nested hollow materials for efficient visible-light-driven hydrogen production.