Spatial separation of dual-cocatalysts on one-dimensional semiconductors for photocatalytic hydrogen production

Abstract

Light-driven hydrogen production using semiconductor photocatalysts has gained much interest owing to their ability to store sunlight in the form of portable chemical fuel. The spatial separation of dual-cocatalysts onto different surfaces has been considered as a useful strategy for fabricating dynamic particulate photocatalysts to hinder charge recombination and reverse reactions. Herein, using one-dimensional (1D) semiconductors, CdSe nanorods as an example, we experimentally demonstrated that photogenerated electrons and holes can be effectively separated along different directions of a 1D semiconductor. Following this phenomenon, the reduction cocatalyst Pt and oxidation cocatalyst PdS were spatially deposited on different sites via an in situ photodeposition process, which drastically enhanced the photocatalytic activity for hydrogen production to more than 20 times, thus exhibiting an extremely high apparent quantum efficiency (AQE) of ∼45% at 420 nm. Further studies using photoluminescence spectroscopy indicated that the spatially separated dual-cocatalysts efficiently captured the photogenerated electrons and holes migrating to the surface, which greatly decreased the recombination of charge carriers and consequently led to superior photocatalytic performances. Our work provides an effective strategy for the rational construction of highly efficient photocatalyst systems based on (quasi) 1D semiconductors for artificial solar energy conversion.