An Inorganic/Organic S-Scheme Heterojunction H<sub>2</sub> -Production Photocatalyst and its Charge Transfer Mechanism.

Cheng, Chang; He, Bowen; Fan, Jiajie; Cheng, Bei; Cao, Shaowen; Yu, Jiaguo · Adv Mater · 2021

basic_science · Level V

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Abstract

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), is synthesized via the typical Suzuki-Miyaura reactions, and then employed as a substrate to anchor CdS nanocrystals. The optimized CdS/PT composite, coupling 2 wt% PT with CdS, exhibits a robust H<sub>2</sub> evolution rate of 9.28 mmol h<sup>-1</sup> g<sup>-1</sup> with continuous release of H<sub>2</sub> bubbles, as well as a high apparent quantum efficiency 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 photoirradiated Kelvin probe measurement and in situ irradiated X-ray photoelectron spectroscopy analyses. This work provides a protocol for preparing specific S-scheme heterojunction photocatalysts on the basis of inorganic/organic coupling.