High-response n-butanol gas sensor based on ZnO/In_(2)O_(3) heterostructure

In this study,ZnO/In_(2)O_(3)-heterostructured nanosheets were prepared using a one-step hydrothermal method.The effects of ZnO content on the gas-sensing performance were discussed,with ZnO/In_(2)O_(3)-2 exhibiting the highest performance among the prepared sensors.The response of ZnO/In_(2)O_(3)-2 to n-butanol was 302 at 26℃,which was 11.93 times higher than that of pure In_(2)O_(3).Among the eight tested gases,ZnO/In_(2)O_(3)-2 displayed the highest response to n-butanol.Moreover,the lower detection limit of the ZnO/In_(2)O_(3)nanosheets was reduced from 10×10^(-6)to 0.1×10^(-6)(for pure In_(2)O_(3)nanosheets)toward n-butanol.This is because the doping of Zn2+increases the number of oxygen vacancies on the sensor surface and allows the formation of an n-n heterostructure between ZnO and In_(2)O_(3),which increases the initial resistance of the sensor.

Electrochemical response of MoS_(2) nanosheets/SiO_(2)-NH_(2) nanoparticles modified glassy carbon electrode to phenylacetic acid

Phenylacetic acid(PAA)is a primary raw material for illegal Methamphetamine(MATM)synthesis under the strong precursor chemicals supervisions of safrole and isosafrole.Therefore,trace detection of PAA at ultra-low concentration is a strategic technique and an urgent issue in the field of drug control.In this paper,trace determination of PAA at sub-nmol-L-1 concentration level is achieved by hydrogen bond adsorption and electrochemical catalysis through the prepared aminated SiO_(2)nanoparticles(SiO_(2)-NH_(2) NPs)and MoS_(2) nanosheets(NSs)modified glassy carbon electrode(GCE).The prepared MoS_(2) NS s/SiO_(2)-NH_(2) NPs modified electrode represents a detecting limit of 0.0989 nmol·L^(-1)and an obvious increasing linear range before the concentration increasement up to 60 nmol·L^(-1)in square wave voltammetry(SWV)responses of PAA.The SWV response of the modified electrode to PAA in the concentration range within 100 nmol·L^(-1)is higher than phenol,acetic acid(HOAc)and benzoic Acid(BEN).This electrochemical method for trace detection of PAA in aqueous solution with desired performance provides a feasible scheme for the detection of other drugs and aromatic precursor chemicals.