Photo-inactive ZIF-8 is applied to significantly enhance the photocatalytic water reduction by forming a built-in electric field with g-C3N4 and the mechanism analysis

摘要

It has been found in this study that the combination of ZIF-8 and g-C3N4 turns the photo-inactive ZIF-8 into "active" and significantly enhances the photocatalytic performance for H-2 production. The experimental results such as contact potential difference (CPD) and photodeposition analysis suggest that a built-in electric field exists at the interface of g-C3N4 and ZIF-8, and the direction is from ZIF-8 to g-C3N4. Furthermore, the theoretical calculation of charge density difference and work functions uncover the potential forming mechanism of the built-in electric field. The mechanism analysis exhibits that the built-in electric field is conducive to promote the directional transfer of photo-induced electrons from g-C3N4 to ZIF-8, which significantly boosts the catalytic ability. Hence, the construction of a built-in electric field is considered to be an effective strategy to synthesize robust photocatalysts, and the strategy can be extended to prepare a range of advanced catalysts needing directional charge transfer.

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