Construction of intramolecular and interfacial built-in electric field in a donor-acceptor conjugated polymers-based S-scheme heterojunction for high photocatalytic H2 generation

Engineering a robust built-in electric field (IEF) is favorable for boosting carrier separation and achieving high photocatalytic performance. Herein, we developed a donor-acceptor conjugated polymer-based S-scheme heterojunction, utilizing both intramolecular and interfacial IEF to enhance carrier separation and achieve superior photocatalytic performance. Specifically, the intramolecular IEF was established by introducing 1,6-dibromopyrene into carbon nitride (CN) to form 1,6-dibromopyrene grafted CN (CNPy). Concurrently, the S-scheme heterojunction was formed by coupling CNPy with CdSe nanoparticles to create an interfacial IEF. Experimental findings demonstrated that the combined effect of intramolecular and interfacial IEF within the CdSe/CNPy heterojunction significantly improved the carrier separation and retained strong redox capacity. Benefiting from these advantages, the optimized composite, 100%CdSe/CNPy-0.2, showed the highest H2 generation rate of 1.16 mmol·g−1·h−1, surpassing those of pure CNPy-0.2, CdSe and 100%CdSe/CN by 58, 2.2 and 2.32 times, respectively. This study introduces an innovative design strategy for IEF-regulated conjugated polymer-based materials, paving the way for efficient solar-to-chemical energy conversion.