Importance of ZnTiO3 Phase in ZnTi-Mixed Metal Oxide Photocatalysts Derived from Layered Double Hydroxide
Importance of ZnTiO3 Phase in ZnTi-Mixed Metal Oxide Photocatalysts Derived from Layered Double Hydroxide
复制标题
DOI：
10.1021/acsami.9b18785
复制
发表时间：
2020-02-26
影响因子：
9.5
通讯作者：
Sasaki, Keiko
中科院分区：
文献类型：
--
作者：
Chuaicham, Chitiphon;Karthikeyan, Sekar;Sasaki, Keiko
在本研究中，通过改变Zn/Ti的摩尔比、煅烧温度和合成方法（水热或回流），以ZnTi层状双氢氧化物为原料合成了ZnTi混合金属氧化物（ZTM），如ZnTiO3。利用反向双束光声光谱技术，利用电子阱的能量分辨分布研究了ZTM的表面电子特性。在500℃下进行水热合成得到的ZTM样品显示出与Zn/Ti摩尔比无关的相似的ERDT模式，尽管当Zn/Ti摩尔比较高时，在x射线衍射图中未观察到ZnTiO3相。当ERDT模式在500℃热液产物的导带底部附近显示出高电子积累水平时，由于ZnTiO3相的形成，观察到更高的光催化苯酚降解效率。结果表明，高Zn/Ti摩尔比（Zn/Ti = 6）的产物为非晶态ZnTiO3。ZTM光催化性能的增强可以归因于ZnO、TiO2和ZnTiO3之间的电子异质结，这使得复合材料中的电子转移，阻止了电荷的重组，并促进了ZnTiO3相对可见光的更广泛的吸附，而不考虑其结晶度。
In this study, ZnTi-mixed metal oxides (ZTM), such as ZnTiO3, were synthesized from ZnTi layered double hydroxides by varying the molar ratio of Zn/Ti, calcination temperatures, and synthesis methods (hydrothermal or reflux). The surface electronic characteristics of ZTM were investigated by the energy-resolved distribution of electron traps (ERDTs) using reversed double-beam photoacoustic spectroscopy. The ZTM samples obtained by conducting hydrothermal synthesis at 500 degrees C showed similar ERDT patterns independent of the molar ratio of Zn/Ti, although ZnTiO3 phase was not observed in the X-ray diffraction pattern, when the Zn/Ti ratio was high. When the ERDT patterns demonstrated a high electron accumulation level near the conduction band bottom in hydrothermal products at 500 degrees C, a higher photocatalytic phenol degradation efficiency was observed due to the formation of ZnTiO3 phase. This suggested that the product with the high Zn/Ti molar ratio (Zn/Ti = 6) constituted amorphous ZnTiO3.The enhanced photocatalytic performance of ZTM could be attributed to the heterojunction of electrons among ZnO, TiO2, and ZnTiO3, which enabled electron transfer in the composites, prevented charge recombination, and promoted a wider visible light adsorption by ZnTiO3 phase irrespective of its crystallinity.