Ultrasensitive acetone sensors based on bimetallic@In2O3 yolk-shell structures: From structural design to mechanism exploration

Metal oxide gas sensors have been widely used in various applications since their inception and have garnered significant attention. However, achieving accurate and selective detection of acetone at the parts per billion (ppb) level, particularly in high-humidity environments, remains challenging. Here, we present an advanced yolk-shell structure combining of Pt-based bimetals and indium oxide, offering significantly improved acetone detection performance. Specifically, the PtPd@In 2 O 3 sensor exhibits an exceptional detection limit of 20 ppb and a rapid response time of 4 s for acetone. The sensor achieves a response value of 93.44 to 1.8 ppm acetone in a dry environment and maintains at 20.24 under 95 % relative humidity. In-situ infrared diffuse reflectance experiments revealed that the acetone response mechanism deviates from previous assumptions, exhibiting temperature-dependent intermediate phases, particularly at evaluated temperatures. This study not only highlights the potential of PtPd@In 2 O 3 as a high-performance gas sensor but also offers novel insights into the acetone sensing mechanism, paving the way for the development of advanced gas-sensitive materials and innovative structural designs.