Nano-layer based 1T-rich MoS2/g-C3N4 co-catalyst system for enhanced photocatalytic and photoelectrochemical activity
Nano-layer based 1T-rich MoS2/g-C3N4 co-catalyst system for enhanced photocatalytic and photoelectrochemical activity
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DOI：
10.1016/j.apcatb.2019.118466
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发表时间：
2020-07-05
影响因子：
22.1
通讯作者：
Zhang, Xiwang
中科院分区：
文献类型：
--
作者：
Hu, Xiaoyi;Zeng, Xiangkang;Zhang, Xiwang
基于半导体的光催化消毒有望通过利用活性氧(ROS)作为“绿色”杀菌剂来解决生物污染的水问题。然而，由于光生载流子的高重组率与其在表面的捕获催化反应之间的激烈竞争，半导体表面通常会缓慢地灭活细菌。在本研究中，我们基于类似的纳米层状结构，在富含稀土的半导体(g-C3N4)上原位杂化了一种高性价比的助催化剂(MoS_2)。自发合成的MoS2纳米层(5-8层)在1T相中占主导地位，这可能是通过从g-C3N4纳米片中通过完全接触的界面从g-C3N4纳米片中提取电子和加速高导电金属MoS2中的电荷转移，同时相对于边缘活性的2H MoS2在边缘和基面上提供额外的活性中心来实现有效的电荷分离。优化后的1T-富MoS_2/g-C_3N_4纳米复合材料的光电流密度比裸的g-C_3N_4提高了5.5倍，并促进了以H_2O_2为主的ROS的生成，从而获得了比单组分催化剂、富2H催化剂和物理MoS_2/g-C_3N_4混合物更好的光催化水消毒性能。这一策略可能会启发其他有效的助催化剂的构建，作为昂贵的贵金属在光催化反应中的替代品。
Photocatalytic disinfection based on semiconductors has been expected to tackle bio-contaminated water issue by leveraging reactive oxygen species (ROS) as "green" bactericide. However, semiconductor along usually inactivates bacteria tardily due to the fierce competition between high recombination rate of photo-excited charge carriers and the capture of them on surface to catalyse reactions. In this study, we in situ hybridized a cost-effective co-catalyst (MoS2) on an earth-abundant semiconductor (g-C3N4 in nanosheets) based on similar nano-layered configuration. The spontaneously synthesized MoS2 nano-layers (5-8 layers) was dominant in 1 T-phase which was found serviceable for efficient charge separation possibly by extracting electrons from g-C3N4 nanosheets through the fully contacted interface and accelerated charge transfer in highly conductive metallic MoS2, meanwhile affording additional active sites both at edges and on basal plans relative to edge-active 2H MoS2. The optimized 1 T-rich MoS2/g-C3N4 nanocomposite impressively enlarged the photocurrent density by a factor of 5.5 compared to bare g-C3N4 and promoted the formation of H2O2 as the main ROS, thus leading to a better photocatalytic water disinfection performance than those of single component catalysts, 2H-rich counterpart and physical MoS2/g-C3N4 mixture. This strategy would potentially enlighten the construction of other effective co-catalysts as alternatives to the expensive noble metals in catalysing photo-activated reactions.