Kong Ting-Ting, Huang Jian, Jia Xin-Gang, Wang Wen-Zhen, Zhou Yong
College of Chemistry and Chemical Engineering, Xi'an Shiyou University, Xi'an, 710054, Shaanxi, China.
Department of Physics, Nanjing University, Nanjing, 210039, Jiangsu, China.
Sci Rep. 2019 Apr 4;9(1):5659. doi: 10.1038/s41598-019-41979-4.
A series of Ti/Li/Al ternary layered double hydroxides (TiLiAl-LDHs) with different Ti:Li:Al molar ratios were prepared by a coprecipitation method for photocatalytic CO reduction. It was demonstrated that the contents of anions between the layers of Ti/Li/Al-LDHs greatly determined the photocatalytic activity for CO reduction. With Ti:Li:Al molar ratios optimized to be 1:3:2, the largest contents of [Formula: see text] anion and hydroxyl group were obtained for the TiLiAl-LDHs sample, which exhibited the highest photocatalytic activity for CO reduction, with CH production rate achieving 1.33 mmol h g. Moreover, the theoretical calculations show that TiLiAl-LDHs is a p-type semiconductor with the narrowest band gap among all the obtained TiLiAl-LDHs. After calcined at high temperatures such as 700 °C, and the obtained TiLiAl-700 sample showed much increased photocatalytic activity for CO reduction, with CH production rate reaching about 1.59 mmol h g. This calcination induced photocatalytic enhancement should be related to the cystal structure transformation from hydrotalcite to mixed oxides containing high reactive oxygen species for more efficient CO reduction.
通过共沉淀法制备了一系列具有不同Ti:Li:Al摩尔比的Ti/Li/Al三元层状双氢氧化物（TiLiAl-LDHs）用于光催化CO还原。结果表明，Ti/Li/Al-LDHs层间阴离子的含量极大地决定了其光催化CO还原活性。当Ti:Li:Al摩尔比优化为1:3:2时，TiLiAl-LDHs样品获得了最大含量的[公式：见文本]阴离子和羟基，其对CO还原表现出最高的光催化活性，CH生成速率达到1.33 mmol h g。此外，理论计算表明，TiLiAl-LDHs是一种p型半导体，在所有获得的TiLiAl-LDHs中具有最窄的带隙。在700°C等高温下煅烧后，所得的TiLiAl-700样品对CO还原表现出大幅提高的光催化活性，CH生成速率达到约1.59 mmol h g。这种煅烧诱导的光催化增强应与从水滑石到含有高活性氧物种的混合氧化物的晶体结构转变有关，以实现更高效的CO还原。
