Inspired by natural photosynthesis, constructing inorganic/organic heterojunctions is regarded as an effective strategy to design high-efficiency photocatalysts. Herein, a step (S)-scheme heterojunction photocatalyst is prepared by in situ growth of an inorganic semiconductor firmly on an organic semiconductor. A new pyrene-based conjugated polymer pyrene-alt-triphenylamine (PT) was synthesized via the typical Suzuki-Miyaura reactions, and then served as a substrate to anchor CdS nanocrystals. The optimized CdS/PT composite, coupling 2 wt% PT with CdS, exhibits a robust H₂ evolution rate of 9.28 mmol h^-1 g^-1 with continuous release of H₂ bubbles, as well as a high apparent quantum efficiency (AQE) of 24.3%, which is ~8 times that of pure CdS. The S-scheme charge transfer mechanism between PT and CdS, is systematically demonstrated by photo-irradiated Kelvin probe measurement and in situ irradiated X-ray photoelectron spectroscopic analyses. This work provides a protocol for preparing specific S-scheme heterojunction photocatalysts on the basis of inorganic/organic coupling.

S-scheme, inorganic/organic heterojunctions, CdS, polymer pyrene-alt-triphenylamine, apparent quantum efficiency