Pt‐functionalized Amorphous RuOx as Excellent Stability and High‐activity Catalysts for Low Temperature MEMS Sensors

Abstract The unsaturated coordination and abundant active sites endow amorphous metals with tremendous potential in improving metal oxide semiconductors’ gas‐sensing properties. However, the amorphous materials maintain the metastable status and easily transfer into the lower‐active crystals during the gas‐sensing process at high working temperatures, significantly limiting their further applications. Here, a bimetal amorphous PtRu catalyst is developed by accurately regulating the introduction of Pt species into amorphous RuO x supports to realize the highly active and stable H 2 S gas‐sensing detection. It is found that incorporation of low‐concentration Pt species can effectively maintain the amorphous state of initial RuO x and delay the crystallization temperature as high as 100 °C. Further, ex situ XPS and in situ Raman spectroscopy analysis confirm that active Pt species can facilitate H 2 S adsorption by strong Pt‐S coordination and dissociate the sulfur species to the surrounding support, which contribute to the chemisorption and sensitization of H 2 S. Meanwhile, electron transport at the interface between Pt, RuO x and ZnO further activates the reaction process at the surface of the gas‐sensitive material. The final PtRu‐modified ZnO (PtRu/ZnO) sensor enables the detection of H 2 S in the ultra‐low concentration range of 15–2000 ppb with remarkable stability.