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[Display omitted] • Bimetallic MOFs-derived hierarchical WO 3 /ZnWO 4 /CoWO 4 heterostructures are gained. • Morphology and sensing behavior of the samples are tuned by the amounts of ZIFs. • Good selectivity and stability of WO 3 -based composites can be observed at 25 °C. • Abundant polyoxometalate electron acceptors are distributed on the coarse surface. • Sensing mechanism is relied on the rapid transport of carriers and plentiful POMs. Bimetallic MOFs-derived hierarchical WO 3 /ZnWO 4 /CoWO 4 heterostructures were prepared by electrospinning for achieving superior n-butanol-sensing property at low operating temperatures. Porous chain-like structures can gradually transformed into porous mulberry-like structures composed of various accumulated particles as increasing the additive amount of Zn/Co-ZIFs. High selectivity and stability of WO 3 -based composites to 100 ppm n-butanol can be observed at 25 °C, including the large sensitivity of 32 and the fast response/recovery times of 115/179 s. The enhanced gas-sensing performance is primarily ascribed to the increased specific surface area, plentiful polyoxometalate, and effective heterojunctions, obviously promoting surface/interface absorption behavior and electron transport process. [ABSTRACT FROM AUTHOR]

[Display omitted] • The uniformly dispersed ZnS NPs hinder the accumulation of rGO flakes and enlarge the specific surface area, while the heterojunction barrier effect realizes the high-efficiency response recovery of NO 2 at room temperature. • Flexible sensor shows low power consumption and good anti-bending and anti-fatigue performance. • Developed a watch-type wearable room temperature NO 2 detection device, which realizes real-time monitoring of target gas by smart terminals through Bluetooth wireless transmission. Wearable electronics consists of mechanically flexible sensor networks and the corresponding circuit system can provide real-time monitoring and recording of toxic gases. In this work, we present a convenient watch-type wearable nitrogen dioxide (NO 2) sensor based on ZnS nanoparticles/nitrogen-doped reduced graphene oxide (ZnS NPs/N-rGO) as a flexible device. The power consumption of the flexible sensor is as low as 0.52 μW. The response value of the device for 10 ppm NO 2 is 2.2; while the recovery time is 724 s, with a low theoretical limit of detection at 69 ppb, with the device maintaining stable mechanical durability. By reading and analyzing the signal data through wireless bluetooth transmission, the device can provide timely monitoring and early warning for NO 2 leakage. Furthermore, the impressive room-temperature sensing performance of ZnS NPs/N-rGO is attributed to factors of geometrical and electronic effects. More specifically, ZnS NP uniformly dispersed on rGO greatly expands the effective contact area with the target gas molecules, and the built-in electric field formed by the strong charge interaction between them also effectively improves the detection sensitivity. The successful development of this type of wireless wearable sensor provides an effective reference for the future application and development of high-performance, low-power, and lightweight sensing equipment. [ABSTRACT FROM AUTHOR]

• Flower-like NiO-ZnO heterostructure assembled by porous nanosheets was synthesized with the assistance of glucose. • The glucose-assisted NiO-ZnO heterostructure based glycol gas sensors have a high response. • The p–n heterojunctions and enhanced oxygen vacancies are the main reasons for enhanced sensing performance. Heterojunction has been proposed as an effective approach to improve the gas sensing performance with good response and low operating temperature. In this work, a one-step hydrothermal method was employed to synthesize a novel flower-like hierarchical NiO-ZnO (G-NiO-ZnO) heterostructure with the assistance of glucose and further calcination treatment. The gas sensors based on G-NiO-ZnO heterojunction exhibit a response of 142.0 toward 100 ppm glycol at relatively low operating temperature about 140 °C with excellent repeatability and long-term stability, which is mainly attributed to the stable hierarchical porous structure with a large specific surface area and the massive oxygen vacancy defects generated during the synthesis process. In general, this work paves a solid foundation for directly synthesizing G-NiO-ZnO heterojunction in a one-step approach and demonstrates a great practical application potential for efficient glycol gas detecting. [ABSTRACT FROM AUTHOR]