An integrated micro-chip with Ru/Al2O3/ZnO as sensing material for SO2 detection.

SO 2 sensor is highly demanded in the application fields such as environmental protection and food manufactory. Herein, an integrated microsensor is developed for SO 2 gas detection. For the fabrication of microsensor, ZnO nanosheets sensing material is firstly loaded onto the sensing area of the microsensor by using inkjet printing technology. Then, Al 2 O 3 loaded with Ru nanoparticles (Ru/Al 2 O 3 ) as catalyst are locally deposited onto the surface of ZnO nanosheets layer. Gas sensing performance measurements indicate that the fabricated microsensor exhibits a selective response to SO 2 , and a good linear relationship in the range of 5–115 ppm SO 2 gases. Besides, this integrated microsensor has short response and recovery time. On-line mass spectrometry (on-line MS) experiment further reveals the formation of sulfur monoxide (SO ) radical as an intermediate product for SO 2 sensing. During the sensing process, Ru/Al 2 O 3 as catalyst layer brings SO 2 molecules to be broken down into easily detectable species (i.e. SO ), and then ZnO nanosheets with abundant gas transport channels capture the produced SO generating output signals. Therefore, this kind of sensing material configuration exploits the advantage of each element, and makes it possible for trace and selective detection of SO 2 gas. [ABSTRACT FROM AUTHOR]