S-scheme heterostructure based on ultrathin 2D CdS coated W18O49 nanosheets-assembled network for highly-efficient photocatalytic H2 evolution

Ultrathin CdS nanosheets (NSs) are intriguing in photocatalytic hydrogen evolution. Severe photo-corrosion and rapid recombination of electrons and holes, however, impair their applications. To solve this problem, a novel step-scheme (S-scheme) 2D CdS/W18O49 heterostructure with strong interfacial interactions and large contact interface has been successfully designed. Due to the ultrathin structure of CdS, defect-rich W18O49 NSs-assembled network, unique 2D heterostructure and state-of-the-art S-scheme mode, 40 wt% CdS/W18O49 (CW40) shows a prominent photocatalytic H2 production rate of 15.4 mmol g−1 h−1. Besides, the apparent quantum efficiency of CW40 is up to 15.4 % under light at λ = 370 nm. Besides, the as-prepared CW40 can protect CdS from photo-corrosion, exhibiting outstanding stability over 24 h circular reaction. Our work provides an out-of-box solution to broaden the application potential of certain catalysts with inherent drawbacks and offers fresh insight into the design and preparation of highly-efficient 2D heterostructures for versatile applications.