Interface engineering of ZnSnO_(3)-based heterojunctions for room-temperature methanol monitoring

Detecting methanol is of great importance in the organic synthesis industry.Herein,the effective utilization of ZnSnO_(3)-based microstructures for room-temperature methanol monitoring was realized through a template-free approach.ZnSnO_(3)-based heterojunctions with different structures and morphologies were successfully synthesized via regulating the molar ratio of Zn2+and Sn4+sources.And room-temperature sensing properties towards methanol were investigated.Among them,ZnO/ZnSnO_(3) hollow microcubes exhibited an outstanding sensing performance including a high sensitivity(10.16)and a response/recovery time(14/75 s)and a limit of detection(490×10^(-9))towards 5×10^(-6)methanol.Additionally,the synergistic effects of hollow structure with larger specific surface areas(42.277 m^(2)·g^(-1)),the construction of n-n heterojunctions formed at ZnSnO_(3) and ZnO interfaces,the high percentage of dissociative and chemisorbed oxygen are the main causes of the elevated sensing characteristics.Besides,the practical experiment demonstrated that ZnO/ZnSnO_(3) was capable of on-field monitoring methanol in the chemical reaction utilizing H_(2) and CO_(2) as raw materials.Moreover,with the help of density functional theory calculations,the enhanced sensing properties of ZnO/ZnSnO_(3) are due to the special tuning effects of Zn ionic sites on methanol adsorption.

Synthesis and NH_(3)/TMA sensing properties of CuFe_(2)O_(4) hollow microspheres at low working temperature

In this work,CuFe_(2)O_(4) hollow microspheres assembled with nanosheets(CuFe_(2)O_(4) HMANs)were synthesized using a solvothermal method followed by an annealing treatment.The effects of annealing temperature on microstructure,chemical composition and gas sensing characteristics of as-prepared samples were investigated.The results showed that annealing treatment played a crucial role in the final products.All samples demonstrated hollow spherical morphology assembled with nanosheets or nanoparticles.The CuFe_(2)O_(4) HMANs annealed at400℃exhibited the best n-type conductometric sensing properties toward low-concentration NH3 at 100℃and49%RH.The sensor response to 10×10^(-6)NH_(3) was 4.0 with a rapid response time of 32 s,and it even showed a response of 1.2 toward 1×10^(-6)NH3 at the same condition,while a response of 3.95 to trimethylamine(TMA).The CuFe_(2)O_(4) HMANs-based NH_(3) sensor also exhibited good selectivity and excellent reproducibility.Therefore,this work provided a novel promised sensing material of low-concentration NH_(3) and TMA for real-time monitoring.