Recent advances in ethanol gas sensors based on metal oxide semiconductor heterojunctions

Metal oxide semiconductor heterojunctions(MOSHs)can enhance the performance of ethanol gas sen-sors substantially.Ethanol gas sensors based on MOSHs are cost-effective and have excellent sensing response,good selectivity,fast response and recovery,long-term stability or repeatability,a low operating temperature,a facile fabrica-tion process,and versatile applications.This paper reviews the recent advances in gas sensors that are based on MOSHs and the advantages of using them to detect ethanol gas.According to the literature,compared with ethanol gas sen-sors that use single-component sensing materials,the MOSHs exhibit superior performance due to the synergy between the different components,which can amplify the reception and transduction components of the sensor signals.To the best of our knowledge,heterojunctions can be grouped into four main categories as metal oxide/metal oxide,metal oxide/metal sulfide,metal oxide/noble metal,and metal oxide/other materials,including rare-earth metals,g-C_(3)N_(4),and graphene,heterojunctions.The future trends and challenges that would be faced in the development of ethanol gas sensors based on MOSHs are discussed in detail.Finally,critical ideas and thinking regarding the future progress of MOSH-based gas sensors are presented.

Cobalt monosulfide nanofibers:ethanol sensing and magnetic properties

Metal sulfide nanomaterials have attracted great interest because of their excellent properties and promising applications in sensing,energy harvesting,magnetic and optoelectronic devices,especially their well-aligned crystalline nanostructures are highly desirable for the enhanced performance and novel applications.In this study,the cobalt monosulfide(CoS)nanofibers with uniform shape and good crystallinity were firstly obtained via electrospinning and atmospheric calcination routes under controllable conditions.It was found that the CoS nanofibers exhibited ethanol sensing properties at the optimum working temperature of 200℃,the response was 11.6 toward 100×10^(-6) ethanol gas,and the CoS nanofibersbased sensor exhibits a short response time and recovery time of 5 and 6 s at the optimum temperature,respectively,the result also shows that the sensor has good stability after 50 days,which would be a favorable characteristic as a promising sensor.In addition,the Pauli paramagnetic property of CoS nanofibers was also investigated at room temperature.