Journal
JOURNAL OF COLLOID AND INTERFACE SCIENCE
Volume 607, Issue -, Pages 662-675Publisher
ACADEMIC PRESS INC ELSEVIER SCIENCE
DOI: 10.1016/j.jcis.2021.09.001
Keywords
Photocatalytic hydrogen evolution; 0D/2D heterojunction; Ag2S quantum dots (QDs); g-C3N4 nanosheets; Cocatalysts; Charge separation behavior
Categories
Funding
- National Natural Science Foundation of China [51672099, 52073263]
- Sichuan Science and Technology Program [2019JDRC0027, 2019YFG0222]
- Fundamental Research Funds for the Central Universitiesunder [2017-QR-25and ZYGX2019J031]
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The study successfully prepared a novel 0D/2D heterojunction nanocomposite (Ag2S QDs/g-C3N4) with excellent photocatalytic performance, achieving a high hydrogen evolution rate and apparent quantum efficiency. The enhanced activity was attributed to energy band broadening of Ag2S QDs and efficient charge transfer between g-C3N4 and Ag2S QDs. Semiconductor-based quantum dots are shown to be strong candidates for excellent cocatalysts in photocatalysis.
In recent years, the use of quantum dots (QDs) cocatalysts to improve the hydrogen evolution activity from the water splitting of photocatalysts has become a popular research topic. Herein, we successfully prepared a novel 0 dimension/2 dimension (0D/2D) heterojunction nanocomposite (denoted Ag2S quantum dots (QDs)/g-C3N4) with excellent photocatalytic performance by anchoring the Ag2S QDs cocatalyst on the surface of g-C3N4 through a self-assembly strategy. Ag2S QDs with an average particle size of approximately 5.8 nm were uniformly and tightly modified on g-C3N4. The Ag2S QDs/g-C3N4 composite with 0.5 wt% Ag2S QDs loading achieved the highest hydrogen evolution rate of 471.1 mu mol.g(.)(-1)h(-1) with an apparent quantum efficiency (AQE) of 1.48% at 405 nm. Such remarkable hydrogen evolution activity far exceeded that of undoped g-C3N4 and Ag2S nanoparticles (NPs)/g-C3N4. Moreover, it was 2.04 times the activity of Pt/g-C3N4 with Pt as the cocatalyst. The enhanced photocatalytic performance was attributed to the energy band broadening of Ag2S QDs caused by the quantum size effect and the convenient and effective charge transfer between g-C3N4 and Ag2S QDs cocatalysts. The mechanism underlying the enhanced photocatalytic H-2 evolution activity was further proposed. This study demonstrates that semiconductor-based quantum dots are strong candidates for excellent cocatalysts in photocatalysis. (C) 2021 Elsevier Inc. All rights reserved.
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