Fabrication of PbS nanocrystal-sensitized ultrafine TiO2 nanotubes for efficient and unusual broadband-light-driven hydrogen production

Abstract It is highly desired to maximize the use of solar light by developing broadband-light-responsive H2 production system in the field of photocatalysis. Herein, a novel PbS/(Pt–TiO2) nanocomposite with efficient and unusual broadband-light-driven H2 production feature is constructed by using infrared-bandgap PbS nanocrystals as sensitizer of Pt-loaded ultrafine anatase TiO2 nanotubes (Pt–TiO2). After optimizing the component ratio, the resultant PbS/(Pt–TiO2) nanocomposite delivers a H2 production activity of 813 and 186 μmol h−1 under ultraviolet (UV)-visible (Vis)-near-infrared (NIR) and Vis-NIR light irradiation, respectively. Moreover, an apparent quantum yield of 38.6%, 26.2%, 2.43%, 3.21%, 2.17%, 0.36%, 0.11% and 0.01% can be attained from the PbS/(Pt–TiO2) nanocomposite illuminated at 350, 420, 550, 700, 760, 850, 950 and 1064 nm monochromatic light, respectively. The intimate interfacial contacts in the PbS nanocrystals decorated ultrafine TiO2 nanotubes, which serve as the support and electron acceptor of PbS nanocrystals, can effectively promote the photoexcited hot electrons transferring from PbS nanocrystals to TiO2 nanotubes before the thermalization losses, and thus causing the efficient Vis-NIR-light-responsive H2 production activity of the PbS/(Pt–TiO2) nanocomposite. These results provide an intriguing application of infrared-bandgap materials to exploit the low-energy photons of the solar light for constructing efficient and unusual broadband-responsive H2 production system.