Self-template synthesis of double-layered porous nanotubes with spatially separated photoredox surfaces for efficient photocatalytic hydrogen production

Improving charge carriers separation to achieve high photoconversion efficiency in heterogeneous photocatalysts is highly desirable. Herein, heterostructured ZnS@CdS double-layered porous nanotubes (PNTs), in which the spatially separated reduction and oxidation reaction sites lie on the outer and inner shell, respectively, are fabricated through a robust self-template conversion strategy. After selective photo-deposition of Ni and CoOx as dual cocatalysts, Ni nanoparticles as electron collectors and reduction reaction sites are loaded on the outer shell, while CoOx nanoparticles as hole collectors and oxidation reaction sites are loaded on the inner shells. As a result, a novel CoOx/ZnS@CdS/Ni photocatalyst is obtained and shows high visible-light-driven photocatalytic hydrogen production activity owing to the synergistic effect of self-template-derived thin mesoporous heterojunctions and photo-deposition-derived spatially separated dual cocatalysts, which can significantly provide driving force for the ordered transfer of photogenerated electrons and holes toward opposite direction and promote the surface catalytic reaction. Additionally, the facile strategy can be broadened to the preparation of CoOx/ZnSe@CdSe/Ni PNTs with enhanced photocatalytic activity.