Yao Ziyu, Sun Huajun, Sui Huiting, Liu Xiaofang
State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan 430070, China.
School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, China.
Nanomaterials (Basel). 2020 Mar 3;10(3):452. doi: 10.3390/nano10030452.
Design and construction of double heterojunction is favorable to improve the separation and migration efficiency of photogenerated carriers, thus preferably solve the problems of environmental pollution and energy crisis. Herein, TiO nanoparticles (NPs) are in-situ grown on highly conductive TiC nanosheets via low-temperature hydrothermal strategy, and then black phosphorus quantum dots (BPQDs) are introduced on the surface of TiO NPs. Under hydrothermal temperature 120 °C, the BPQDs/TiC@TiO photocatalyst exhibits remarkable enhanced photocatalytic degradation of methyl orange (MO) and hydrogen evolution reaction (HER) compared with BPQDs/TiC and TiC@TiO composites. Enhanced photocatalytic activity can be attributed to (i) the BPQDs with tunable bandgaps are deposited on the TiO NPs to form intimate heterojunction, which facilitates the electrons transfer from the conduction band (CB) of BPQDs to the CB of TiO; (ii) the electrons quickly migrate from CB of TiO NPs to the TiC nanosheets with excellent electronic conductivity via electron transfer channel, which is beneficial to prolong the lifetime of electrons and hinder the recombination of photogenerated carriers; (iii) the enhanced visible light absorption and enlarged specific surface area of BPQDs/TiC@TiO further accelerate the photocatalytic reaction. This work emphasizes the essential role of quantum dots in the construction of double heterojunction and the potential application of TiC MXene for improving photocatalytic activity.
双异质结的设计与构建有利于提高光生载流子的分离和迁移效率，从而较好地解决环境污染和能源危机问题。在此，通过低温水热法在高导电性的TiC纳米片上原位生长TiO纳米颗粒（NPs），然后在TiO NPs表面引入黑磷量子点（BPQDs）。在水热温度120℃下，与BPQDs/TiC和TiC@TiO复合材料相比，BPQDs/TiC@TiO光催化剂对甲基橙（MO）的光催化降解和析氢反应（HER）表现出显著增强。增强的光催化活性可归因于：（i）具有可调带隙的BPQDs沉积在TiO NPs上形成紧密的异质结，促进电子从BPQDs的导带（CB）转移到TiO的CB；（ii）电子通过电子转移通道从TiO NPs的CB快速迁移到具有优异电子导电性的TiC纳米片上，这有利于延长电子寿命并阻碍光生载流子的复合；（iii）BPQDs/TiC@TiO增强的可见光吸收和增大的比表面积进一步加速了光催化反应。这项工作强调了量子点在双异质结构建中的重要作用以及TiC MXene在提高光催化活性方面的潜在应用。
