Fullerene–Graphene Acceptor Drives Ultrafast Carrier Dynamics for Sustainable CdS Photocatalytic Hydrogen Evolution
Wenchao Wang, Ying Tao, Jinchen Fan, Zhiping Yan, Huan Shang, David Lee Phillips, Ming Chen, Guisheng Li
Abstract
Abstract Ultrafast excited‐state decay and intrinsic charge carrier recombination restrain the photoactivity enhancement for solar‐to‐H 2 production. Here, a CdS‐fullerene/graphene (CdS‐F/G) photocatalyst is synthesized for enhancing visible‐light‐driven hydrogen generation from earth‐abundant water. The CdS‐F/G shows ultrafast interfacial electrons/holes transfer and holes self‐trapping process in photocatalysis. The in‐situ dynamic study from transient absorption spectroscopy reveals the sub‐microsecond‐lived excited states (≈172.6 ns), interfacial electron transfer (≈30.3 ps), and hole trapping (≈44.0 ps) in the CdS‐F/G photocatalyst. The efficient active species transportation and prolonged lifetime significantly enhance the charge separation state survival, increasing the photoactivity and photostability. Consequently, visible‐light activity enhancement (>400%) of H 2 evolution reaction (HER) is obtained at the CdS‐F/G photocatalyst with high stability (>36 h). The 127.2 µmol h −1 g −1 performance corresponding to a quantum efficiency of 7.24% at 420 nm is not only higher than the case of pristine CdS (29.2 µmol h −1 g −1 ) but also much higher than that of CdS‐Pt photocatalyst (73.8 µmol h −1 g −1 ). The cost‐effective CdS‐F/G photocatalyst exhibits a great potential for sustainable and high‐efficiency photocatalytic water splitting into clean energy carriers. Moreover, the optimized electronic structure associated with interfacial electrons/holes transfer and holes self‐trapping promotes overall water splitting for H 2 and O 2 generation.