Construction of electron donor-acceptor Z-scheme heterojunction for boosting photocatalytic H-2 production

Key Words:G-C3N4; DEFECTS

Abstract:Enhancing the solar energy conversion of metal-free graphitic carbon nitride (g-C3N4) based photocatalyst remains a great challenge. Herein, a novel Z-scheme heterojunction photocatalyst is constructed by in-situ anchoring Pt-6 NCs on carbon self-doping g-C3N4 (CCN/Pt-6 NCs) for boosting photocatalytic H-2 evolution activity. Remarkably, the optimized CCN/Pt-6 NCs photocatalyst exhibits high H2 evolution rate of 6.32 mmol.h(-1).g(-1) and 36.25 mmol.h(-1).g(-1), which is approximate to 150.5 and approximate to 412 times than that of pristine CN under visible light (lambda > 420 nm) and full solar spectrum irradiation, respectively, outperforming majority of the reported g-C3N4-based photocatalysts. Systematic characterizations have revealed that CCN with delocalized electrons and larger the work function is deemed to be a preferable electron-acceptor. Meanwhile, Pt-6 NCs with appropriate HOMO-LUMO level is regarded as an electron-donor. Theoretical and experimental works reveal that the favorable photocatalytic performance of CCN/Pt-6 NCs heterojunction is mainly attributed to the giant internal electric field induced donor-acceptor interaction, which achieves Z-scheme charge transfer mechanism. This work opens up new insights for rational fabrication of metal-free g-C3N4 based photocatalysts to boost the solar energy conversion.

Volume:635

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Translation or Not:no