Metal-Organic Framework-derived Au-ZnO Nanostructures for Ultrasensitive and Selective H₂S Gas Detection

Au-ZnO nanostructures derived from zeolitic imidazolate framework-8 (ZIF-8) were rationally designed and investigated as highly efficient chemiresistive sensors for detecting H₂S gas. The incorporation of Au nanoparticles markedly enhanced the sensing characteristics relative to pristine ZnO, delivering an extraordinary response of ~419.1 toward 10 ppm H₂S at 200 °C—nearly two orders of magnitude higher than that of bare ZnO. The optimized Au-ZnO 2 sensor demonstrated excellent selectivity against interfering gases (NO₂, NH₃, H₂, and volatile organics), fast response/recovery dynamics, and reliable detection down to 0.2 ppm, maintaining stable operation under repeated cycling. Structural and spectroscopic analyses revealed that Au nanoparticles were uniformly anchored on the porous ZnO surfaces, establishing abundant catalytic sites and Au-ZnO Schottky junctions that facilitate charge transfer and accelerate surface reactions. The superior sensing performance arises from the synergistic effects of Au-induced catalytic dissociation, spillover phenomena, and interfacial electronic modulation within the MOF-derived porous framework. This study provides a clear structure-performance correlation and demonstrates a scalable strategy for developing noble-metal/semiconductor hybrid gas sensors with outstanding sensitivity, selectivity, and long-term stability for practical toxic-gas monitoring applications.