A micron-scale bilayer sensor was fabricated in situ by electrohydrodynamic jet printing for detecting H₂ gas with highly selectivity, sensitivity and stability. The sensor consisted of a Pt loaded mesocellular silica foam (PtMCF) catalytic filter layer, and a ZnO/SnO₂/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 H₂ in interfering gases of CO₂ and CH₄ due to its high specific response to H₂. In the ZSA sensing layer, the n-n heterojunction (ZnO-SnO₂) and abundant active sites on the Undaria pinnitafida-like curved nanosheet structure effectively enhanced the response of H₂ by 6.7 times. The sensors exhibited a wide H₂ dynamic range of 0.5-500 ppm with low detection limit of 94 ppb. The response/recovery time to 50 ppm H₂ 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.