Selective detection of H2 by Pt-MCF/ZSA bilayer sensor prepared in situ via EHD jet printing
A micron-scale bilayer sensor was fabricated in situ by electrohydrodynamic jet printing for detecting H 2 gas with highly selectivity, sensitivity and stability. The sensor consisted of a Pt loaded mesocellular silica foam (Pt-MCF) catalytic filter layer, and a ZnO/SnO 2 /Au (ZSA) sensing layer. Benefiting from the selective catalytic oxidation for CO in the catalytic filter layer, the cross-interference of CO on this sensor was reduced from 58 % to 15 %. The sensor also demonstrated a satisfactory selectivity to H 2 in interfering gases of CO 2 and CH 4 due to its high specific response to H 2 . In the ZSA sensing layer, the n-n heterojunction (ZnO-SnO 2 ) and abundant active sites on the Undaria pinnitafida -like curved nanosheet structure effectively enhanced the response of H 2 by 6.7 times. The sensors exhibited a wide H 2 dynamic range of 0.5–500 ppm with low detection limit of 94 ppb. The response/recovery time to 50 ppm H 2 was 24 s/35 s. The sensor also showed good long-term stability in 28-day response-repeatability measurement (RSD=5.3 %) and good anti-humidity.
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