TY - JOUR
T1 - Importance of ZnTiO3 Phase in ZnTi-Mixed Metal Oxide Photocatalysts Derived from Layered Double Hydroxide
AU - Chuaicham, Chitiphon
AU - Karthikeyan, Sekar
AU - Song, Jun Tae
AU - Ishihara, Tatsumi
AU - Ohtani, Bunsho
AU - Sasaki, Keiko
N1 - Funding Information:
This work was supported by the Japan Society for the Promotion of Science (JSPS) KAKENHI Grant Number JP19H00883, Cooperative Research Programs at Hokkaido University Institute for Catalysis (Nos. 18A1001 and 19B1002) and “Progress 100” (World Premium International Researcher Invitation Program) in Kyushu University through operating expense grants of the Ministry of Education, Culture, Sports, Science and Technology. S. K. thanks the JSPS (P18387) and the research grant (KAKENHI JP18F18387). Part of this work was conducted at Kyushu University, supported by Nanotechnology Platform Program (Molecule and Material Synthesis) of the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan.
Publisher Copyright:
Copyright © 2020 American Chemical Society.
PY - 2020/2/26
Y1 - 2020/2/26
N2 - 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 °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 °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.
AB - 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 °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 °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.
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U2 - 10.1021/acsami.9b18785
DO - 10.1021/acsami.9b18785
M3 - Article
C2 - 32064859
AN - SCOPUS:85080955189
VL - 12
SP - 9169
EP - 9180
JO - ACS applied materials & interfaces
JF - ACS applied materials & interfaces
SN - 1944-8244
IS - 8
ER -