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Au Nanoparticles Decorated Mesoporous SiO 2 –WO 3 Hybrid Materials with Improved Pore Connectivity for Ultratrace Ethanol Detection at Low Operating Temperature
Author(s) -
Ma Junhao,
Li Yanyan,
Zhou Xinran,
Yang Xuanyu,
Alharthi Fahad A.,
Alghamdi Abdulaziz A.,
Cheng Xiaowei,
Deng Yonghui
Publication year - 2020
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.202004772
Subject(s) - mesoporous material , materials science , nanoparticle , mesoporous silica , chemical engineering , nanotechnology , etching (microfabrication) , catalysis , chemistry , organic chemistry , layer (electronics) , engineering
Abstract Semiconducting metal oxides‐based gas sensors with the capability to detect trace gases at low operating temperatures are highly desired in applications such as wearable devices, trace pollutant detection, and exhaled breath analysis, but it still remains a great challenge to realize this goal. Herein, a multi‐component co‐assembly method in combination with pore engineering strategy is proposed. By using bi‐functional (3‐mercaptopropyl) trimethoxysilane (MPTMS) that can co‐hydrolyze with transition metal salt and meanwhile coordinate with gold precursor during their co‐assembly with PEO‐ b ‐PS copolymers, ordered mesoporous SiO 2 –WO 3 composites with highly dispersed Au nanoparticles of 5 nm (mesoporous SiO 2 –WO 3 /Au) are straightforward synthesized. This multi‐component co‐assembly process avoids the aggregation of Au nanoparticles and pore blocking in conventional post‐loading method. Furthermore, through controlled etching treatment, a small portion of silica can be removed from the pore wall, resulting in mesoporous SiO 2 –WO 3 /Au with increased specific surface area (129 m 2 g −1 ), significantly improved pore connectivity, and enlarged pore window ( > 4.3 nm). Thanks to the presence of well‐confined Au nanoparticles and ε‐WO 3 , the mesoporous SiO 2 –WO 3 /Au based gas sensors exhibit excellent sensing performance toward ethanol with high sensitivity ( R a / R g = 2–14 to 50–250 ppb) at low operating temperature (150 ° C).