Perception-transduction-transmission separation bionic H2S sensor

Abstract

Achieving high selectivity, high sensitivity, and superior conductivity simultaneously for chemiresistive gas sensors (CGS) remains a significant challenge due to inherent trade-offs among the material's properties. Inspired by biological olfaction, we design and fabricate a Ni-MOF/SnO₂ heterojunction as a perception-transduction-transmission separation membrane for bionic CGS, where Ni-MOF acts as a selective perception layer for H₂S, SnO₂ serves as the electron transmission and proton blocking layer, while the heterojunction enables efficient signal transduction from perception to transmission. The sensor demonstrates exceptional performance, including fingerprint-level selectivity, high moisture stability, and an ultra-low detection limit of 10 ppb. Notably, the sensor operates based on the heterojunction rectification enhancement model. The sensitivity is solely determined by the Ni-MOF perception layer, while the baseline current is governed by the SnO₂ transmission layer. By reducing the resistance of SnO₂, the net response is geometrically amplified. Additionally, applying a bias voltage enables geometric acceleration of the response/recovery rates. This study proposes a novel strategy for designing high-performance CGS.