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

Abstract

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.