Ultrathin WO<sub>3</sub> Nanosheets/Pd with Strong Metal–Support Interactions for Highly Sensitive and Selective Detection of Mustard-Gas Simulants
Haizhen Li, Gang Wu, Jina Wu, Jun Shen, Likun Chen, Jingjing Zhang, Yuyin Mao, Hefeng Cheng, Maolin Zhang, Qingyu Ma, Yongchao Zheng
Abstract
Exposure to mustard gas can cause damage or death to human beings, depending on the concentration and duration. Thus, developing high-performance mustard-gas sensors is highly needed for early warning. Herein, ultrathin WO 3 nanosheet-supported Pd nanoparticles hybrids (WO 3 NSs/Pd) are prepared as chemiresistive sulfur mustard simulant (e.g., 2-chloroethyl ethyl sulfide, 2-CEES) gas sensors. As a result, the optimal WO 3 NSs/Pd-2 (2 wt % of Pd)-based sensor exhibits a high response of 8.5 and a rapid response/recovery time of 9/92 s toward 700 ppb 2-CEES at 260 °C. The detection limit could be as low as 15 ppb with a response of 1.4. Moreover, WO 3 NSs/Pd-2 shows good repeatability, 30-day operating stability, and good selectivity. In WO 3 NSs/Pd-2, ultrathin WO 3 NSs are rich in oxygen vacancies, offer more sites to adsorb oxygen species, and make their size close to or even within the thickness of the so-called electron depletion layer, thus inducing a large resistance change (response). Moreover, strong metal–support interactions (SMSIs) between WO 3 NSs and Pd nanoparticles enhance the catalytic redox reaction performance, thereby achieving a superior sensing performance toward 2-CEES. These findings in this work provide a new approach to optimize the sensing performance of a chemiresistive sensor by constructing SMSIs in ultrathin metal oxides.