Highly efficient photocatalytic activity and mechanism of Yb3+/Tm3+ codoped In2S3 from ultraviolet to near infrared light towards chromium (VI) reduction and rhodamine B oxydative degradation
Highly efficient photocatalytic activity and mechanism of Yb3+/Tm3+ codoped In2S3 from ultraviolet to near infrared light towards chromium (VI) reduction and rhodamine B oxydative degradation
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Yb3 /Tm3共掺杂In2S3从紫外到近红外光对铬（VI）还原和罗丹明B氧化降解的高效光催化活性和机理
DOI：
10.1016/j.apcatb.2017.11.040
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发表时间：
2018-06-05
影响因子：
22.1
通讯作者：
Wang, Hou
中科院分区：
文献类型：
--
作者：
Wu, Zhibin;Yuan, Xingzhong;Wang, Hou
通过水热法合成了Yb3+/Tm3+共掺杂花状四方In2S3光催化剂，并对其晶相、形貌、化学组成和光学性能进行了表征。结果表明，Yb3+/Tm3+的掺杂并没有显着改变In2S3的结晶度，而是诱导中间能态的产生，从而实现有效的电荷分离。 Yb3+/Tm3+ 共掺杂 In2S3 对铬 (VI) 还原和罗丹明 B 氧化（从紫外光到近红外光）的光活性显着增强。 In3+:Yb3+:Tm3+摩尔比为159:40:1的样品获得了最佳的光催化协同作用，其中铬(VI)还原效率分别为97.9%(NIR，100 min)、99.3%(vis，10 min)和98.3%(UV，10 min)，罗丹明B降解效率为98.4% （近红外，100 分钟）、97.3%（可见光，14 分钟）和 96.3%（紫外，14 分钟）。良好的近红外光活性主要归因于Yb3+/Tm3+能级跃迁的上转换机制。在全光谱光照射6 min和7 min下，铬(VI)和罗丹明B的去除率分别达到99.4%和94.8%，相应的速率常数分别是纯In2S3的2.17和5.60倍。光催化效率的提高可能归因于中间能态和/或硫空位导致的光吸收增强和有利的电荷分离。此外，还进行了自由基捕获和电子自旋共振实验，以确定中心点O-2(-)和h(+)物种在光催化氧化过程中的作用。
The Yb3+/Tm3+ codoped flower-like tetragonal In2S3 photocatalysts were synthesized through a hydrothermal route, and the crystal phases, morphologies, chemical compositions and optical properties were characterized. The results shown that the doping with Yb3+/Tm3+ did not significantly change the crystallinity of In2S3, but induced the generation of intermediate energy states for efficient charge separation. The Yb3+/Tm3+ codoped In2S3 presented a significant enhancement of photoactivity towards chromium (VI) reduction and rhodamine B oxidation from UV to NIR light. The best photocatalytic synergism was obtained for the sample with the mole ratio of In3+:Yb3+:Tm3+ at 159:40:1, in which the chromium (VI) reduction efficiency was 97.9% (NIR, 100 min), 99.3% (vis, 10 min) and 98.3% (UV, 10 min), while the rhodamine B degradation efficiency was 98.4% (NIR, 100 min), 97.3% (vis, 14 min), and 96.3% (UV, 14 min). The favorable NIR photoactivity was mainly attributed to the upconversion mechanism via energy level transition of Yb3+/Tm3+. Under the full-spectra-light irradiation for 6 min and 7 min, the removal efficiency of chromium (VI) and rhodamine B could reach to 99.4% and 94.8%, the corresponding rate constant was 2.17 and 5.60 times of pure In2S3, respectively. The improved photocatalytic efficiency might be attributed to the enhanced light absorption and favorable charge separation resulted from the intermediate energy states and/or sulfur vacancies. In addition, the free radical capture and electron spin resonance experiments were also performed to determined the role of center dot O-2(-) and h(+) species during photocatalytic oxidation process.