Room‐Temperature Selectivity Switching via Nanoporous Au Film‐Integrated SnO 2 Hybrid Sensors

ABSTRACT Metal oxide chemiresistive sensors operating at room temperature offer a promising route toward low‐power gas monitoring, but their selectivity remains largely governed by the intrinsic surface chemistry of the oxide. Here, we report a transport‐engineered Au nanoporous metal film (Au NPMF)‐integrated tin dioxide (SnO 2 ) hybrid structure (Au NPMF@SnO 2 ) that reverses the native sensing preference of SnO 2 at room temperature. A continuous Au NPMF is conformally integrated with glancing‐angle‐deposited SnO 2 nanorods through a plasma‐assisted dry process, producing a permeable metal/oxide interface while preserving the structural and chemical identity of the oxide scaffold. The Au NPMF does not merely function as a catalytic decoration, but as an interconnected transport‐regulating overlayer that modulates gas access, adsorption, and release before molecules reach the SnO 2 surface. Consequently, the intrinsic NO 2 ‐dominant behavior of pristine SnO 2 is switched to H 2 S‐selective sensing, with improved H 2 S recovery, stable cycling performance, and a theoretical detection limit of 0.0087 ppm. This behavior is primarily associated with the continuous nanoporous Au architecture, which couples morphology‐controlled gas accessibility with gas‐specific adsorption–desorption behavior and interfacial electronic interactions. These findings establish nanoporous metal overlayers as programmable interfacial layers for room‐temperature selectivity control in metal oxide gas sensors.