Ultrasensitive Exhaled H2S Sensor Enabled by Pt@ZIF-8/Cu2O Heterostructures.

The rapid and accurate detection of H2S in exhaled breath at room temperature remains a critical technical challenge. Herein, we developed a Pt@ZIF-8/Cu2O heterojunction sensor via a two-dimensional electrodeposition in-situ assembly strategy for sensitive H2S detection. This sensor exhibits superior room-temperature sensing performance: a remarkably high response of 8931 toward 10 ppm of H2S, an ultralow detection limit of 10 ppb (response ∼0.61), and a 11.8-fold enhancement in response to 500 ppb H2S relative to pristine Cu2O. The exceptional sensing performance is attributed to the synergistic effects of the high-specific-surface-area structure, the catalytic activity of Pt nanoparticles, and optimized interfacial charge transfer at the heterojunction. Notably, as the relative humidity increases from 37 to 94%, the response time toward 5 ppm of H2S decreased by ∼33% (from 330 to 220 s), while the response magnitude concurrently increases by ∼117% (from 3183 to 6907). This humidity-induced performance improvement significantly enhances operational reliability in practical applications, thereby eliminating the requirement for complex humidity control systems. This unique phenomenon is associated with the [Zn-OH]+ active sites within the ZIF-8 framework, which facilitate the adsorption of H2S molecules. More importantly, the sensor enables sensitively quantification of H2S concentrations in human exhaled breath, highlighting its great potential for noninvasive disease diagnosis.