Ultrasmall graphitic carbon nitride quantum dots decorated self-organized TiO2 nanotube arrays with highly efficient photoelectrochemical activity
Ultrasmall graphitic carbon nitride quantum dots decorated self-organized TiO2 nanotube arrays with highly efficient photoelectrochemical activity
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DOI：
10.1016/j.apcatb.2015.12.050
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发表时间：
2016-06-05
影响因子：
22.1
通讯作者：
Chen, Guohua
中科院分区：
文献类型：
--
作者：
Su, Jingyang;Zhu, Lin;Chen, Guohua
采用电化学阳极氧化和有机分子键合两步法制备了一种新型的石墨碳氮量子点（CNQDs）修饰的TiO 2纳米管阵列（NTAs）光电极。发现CNQD对TiO 2的成功修饰可以显着提高光电化学活性，因为增强了光吸收并改善了光生电子-空穴对的分离。在模拟太阳光照射下，在中性溶液中，CNQDs/TiO 2 NTAs在0.3V（vsAg/AgCl）下的光电流是单独使用TiO 2 NTAs的3.5倍，最大光电转换效率达到0.63%。此外，所制备的CNQD/TiO 2 NTAs对RhB的光电催化降解表现出良好的上级活性和稳定性，其动力学常数是TiO 2 NTAs的3.0倍。羟基自由基和超氧阴离子自由基是污染物降解过程中的主要活性自由基。此外，制备的CNQD/TiO 2样品用作光阳极，在模拟太阳光照射下直接光电化学分解水产生H-2和O-2，在0.3 V（相对于Ag/AgCl）下，H-2产生速率为22.0 μ mol h（-1）cm（-2）。(C)2015 Elsevier B. V.版权所有。
In the present study, a novel graphitic carbon nitride quantum dots (CNQDs) modified TiO2 nanotube arrays (NTAs) photoelectrode was successfully synthesized by a simple two-step method which includes an electrochemical anodization technique followed by a facile organic molecular linkage. The successful modification of TiO2 by CNQDs was found to improve the photoelectrochemical activity significantly because of enhanced light absorption and improved separation of photo-generated electron-hole pairs. The optimized CNQDs/TiO2 NTAs showed nearly 3.5-fold photocurrent of that from TiO2 NTAs alone at 0.3 V vs Ag/AgCl and the maximum photoconversion efficiency reaches up to 0.63% in neutral solution under simulated solar light irradiation. Furthermore, the prepared CNQD/TiO2 NTAs demonstrated superior photoelectrocatalytic activity and stability in the degradation of RhB, with kinetic constants 3.0 times of that from TiO2 NTAs. The hydroxyl and superoxide radicals were proved to be the dominant active radicals during pollutants degradation. Additionally, the prepared CNQD/TiO2 sample was used as photoanodes for direct photoelectrochemical water splitting to produce H-2 and O-2 under simulated solar light illumination, achieving a H-2 production rate with 22.0 mu mol h(-1) cm(-2) at 0.3 V vs Ag/AgCl. (C) 2015 Elsevier B.V. All rights reserved.