Three-dimensional S-scheme heterojunction by integration of purple tungsten oxide nanowires and cadmium sulfide nanospheres for effective photocatalytic hydrogen generation.

[Display omitted] The practical photocatalytic application of cadmium sulfide (CdS) has been significantly constrained by fast carrier recombination and significant photocorrosion. Therefore, we developed a three-dimensional (3D) step-by-step (S-scheme) heterojunction using the coupling interface between purple tungsten oxide (W 18 O 49) nanowires and CdS nanospheres. The photocatalytic hydrogen evolution rate of optimized W 18 O 49 /CdS 3D S-scheme heterojunction can reach 9.7 mmol·h−1·g−1, 7.5 and 16.2 times greater than pure CdS (1.3 mmol·h−1·g−1) and 10 wt%-W 18 O 49 /CdS (mechanical mixing, 0.6 mmol·h−1·g−1), proving that the tight S-scheme heterojunction constructed by the hydrothermal method can efficiently enhance the carrier separation. Notably, the apparent quantum efficiency (AQE) of W 18 O 49 /CdS 3D S-scheme heterojunction approaches 7.5% and 3.5% at 370 nm and 456 nm, respectively, which is 7.5 and 8.8 times than pure CdS (1.0% and 0.4%). The produced W 18 O 49 /CdS catalyst also has relative stability of structure and hydrogen production. Additionally, the H 2 evolution rate of W 18 O 49 /CdS 3D S-scheme heterojunction is 1.2 times greater than 1 wt%-platinum (Pt)/CdS (8.2 mmol·h−1·g−1), which indicates that the W 18 O 49 can effectively replace the precious metal for boosting the hydrogen production rate. [ABSTRACT FROM AUTHOR]