Tubular g-C3N4 Isotype Heterojunction: Enhanced Visible-Light Photocatalytic Activity through Cooperative Manipulation of Oriented Electron and Hole Transfer

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• 作者：Zhenwei Tong ; Dong Yang ; Yuanyuan Sun ; Yanhu Nan and Zhongyi Jiang
• 刊名：Small
• 出版年：2016
• 出版时间：August 10, 2016
• 年：2016
• 卷：12
• 期：30
• 页码：4093-4101
• 全文大小：1063K
• ISSN：1613-6829

文摘

A tubular g-C₃N₄ isotype heterojunction (TCNH) photocatalyst was designed for cooperative manipulation of the oriented transfer of photogenerated electrons and holes to pursue high catalytic performance. The adduct of cyanuric acid and melamine (CA·M) is first hydrothermally treated to assemble into hexagonal prism crystals; then the hybrid precursors of urea and CA·M crystals are calcined to form tubular g-C₃N₄ isotype heterojunctions. Upon visible-light irradiation, the photogenerated electrons transfer from g-C₃N₄ (CA·M) to g-C₃N₄ (urea) driven by the conduction band offset of 0.05 eV, while the photogenerated holes transfer from g-C₃N₄ (urea) to g-C₃N₄ (CA·M) driven by the valence band offset of 0.18 eV, which renders oriented transfer of the charge carriers across the heterojunction interface. Meanwhile, the tubular structure of TCNH is favorable for oriented electron transfer along the longitudinal dimension, which greatly decreases the chance of charge carrier recombination. Consequently, TCNH exhibits a high hydrogen evolution rate of 63 μmol h⁻¹ (0.04 g, λ > 420 nm), which is nearly five times of the pristine g-C₃N₄ and higher than most of the existing g-C₃N₄ photocatalysts. This study demonstrates that isotype heterojunction structure and tubular structure can jointly manipulate the oriented transfer of electrons and holes, thus facilitating the visible-light photocatalysis.