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[Display omitted] The metal oxides-based chemiresitive gas sensors have attracted enormous interest because of their exellent sensing perforamcnes, which have emerged as very promising candidates for gas monitoring. However, from the view of organophosphorus compounds detection, a unique combination of low detection limit and fast respons/recovery rate remains challenging. Herein, the synersgitic effects of oxygen vacancy engineering and surface gold decoration enabling excellent sensing performances for detection of dimethyl methyl phosphonate (DMMP, a typical organophosphorus) is reported. To demonstrate the proof of concept, Au nanoparticles (NPs) decorated oxygen vacancy-enriched SnO 2 hybrids (designated as Au-O-SnO 2) were designed as sensing materials, where the O-SnO 2 samples were fabricated by introduction of oxygen vacancies onto commercial SnO 2 through organometallic chemistry-assisted approach using (CH 3) 2 SnCl 2 as precursor, followed by deposition of Au NPs by an in-situ reduction routine. After optimizing Au NPs content in hybrids (1 wt%, 3 wt%, 5 wt% and 7 wt%), O-SnO 2 decorated with 5 wt% Au NPs (designated as Au-O-SnO 2 -5) exhibits excellent DMMP sensing performances, such as, an enhanced recoverable response of 1.67 to 680 ppb DMMP, low detection limit of 4.8 ppb, short response time of 26 s and recovery time of 32 s, as well as good selectivity, which are much better than that of commercial SnO 2 (C-SnO 2) and O-SnO 2 , and Au NPs decorated C-SnO 2. Based on the detailed investigation, the enhanced DMMP sensing performances of Au-O-SnO 2 hybrids can be mainly ascribed to the synergistic effect of increasing surface active sites induced by oxygen vacancies, the chemical and electronic sensitization of Au NPs. As a result, Au-O-SnO 2 -5 hybrids display relatively low activation energy of 24.11 kJ/mol for DMMP oxidization, which is lower than that of O-SnO 2 (35.54 kJ/mol). Our results provide a feasible method for boosting sensing performances for DMMP detection, paving new way for fabrication of metal oxides-based gas sensors for rapid detection of trace organic compounds with complexed structures. [ABSTRACT FROM AUTHOR]

The development of metal oxides-based gas sensors for DMMP detection simultaneously possessing low operating temperature, low limit of detection and high sensitivity remains formidable challenges. In this work, a facile and efficient colloidal assembly approach is proposed to prepare Au modified SnO 2 hybrids (Au-SnO 2) with perfect metal-semiconductor interface and successfully used in DMMP detection application. After optimization, the best DMMP sensors based on Au-SnO 2 hybrids display outstanding sensing performances, including high response (1.88 to 680 ppb DMMP), low operating temperature (200 °C), extremely low limit of detection (34 ppb), as well as short response/recovery time (25 s/72 s). The sensing mechanism analysis reveals that the excellent sensing performances are mainly attributed to the synergy of chemical oxidation of DMMP catalyzed by Au-SnO 2 hybrids and physical adsorption of DMMP by hydrogen-bonding interactions. The present work not only provides an insight into the DMMP sensing mechanism, but also offers a promising general approach for development of high-performance gas sensors. [Display omitted] • A facile and efficient colloidal assembly approach waa proposed to synthesize Au modified SnO 2 hybrids. • The Au-SnO 2 -based sensor exhibits high response of 1.88 towards 680 ppb DMMP. • The limit of detection of the Au-SnO 2 -based sensor was 34 ppb. • An integrated chemical oxidation and hydrogen-bonding DMMP sensing mechanism model was first proposed. [ABSTRACT FROM AUTHOR]