Highly sensitive detection of HS gas at low temperature based on ZnCoO microtube sensors.

It is extremely necessary to detect Hydrogen sulfide (HS) due to the hazardous nature. Thus, it is required to design a material which can detect HS gas at low temperature. In this work, ZnCoO microtubes are prepared by using absorbent cotton as template, combining immersion method in metal salt solution (Zn:Co=1:2) with calcination treatment in air. The influence of calcination temperature on the particle size and sensing property was also discussed. The diameter of particles on the ZnCoO microtubes increases with increasing calcination temperature. The hollow microtubes of ZnCoO materials calcined at 600 °C (ZCO-600) exhibit superb sensing performance to HS at 90 °C with the lowest detection limit of 50 ppb. The optimum operating temperature (90 °C) was lower than the other reported ZnCoO sensors. ZCO-600 sensor also shows excellent selectivity, repeatability, stability, humidity resistance and the good linear relationship in ppb and ppm level HS. In addition, the feasible sensing mechanism of ZCO-600 to HS is explored on the basis of XPS analysis. Thus, ZnCoO as a sensing material possesses widespread application prospects for the detection of trace HS gas.