Anchoring Platinum Clusters onto Oxygen Vacancy-Modified In2O3for Ultraefficient, Low-Temperature, Highly Sensitive, and StableDetection of Formaldehyde

To avoid carcinogenicity, formaldehyde gas, currentlybeing only detected at higher operating temperatures, should beselectively detected in time with ppb concentration sensitivity in aroom-temperature indoor environment. This is achieved in this workthrough introducing oxygen vacancies and Pt clusters on the surface ofIn2O3to reduce the optimal operating temperature from 120 to 40 degrees C.Previous studies have shown that only water participates in thecompetitive adsorption on the sensor surface. Here, we experimentallyconfirm that the adsorbed water on the fabricated sensor surface isconsumed via a chemical reaction due to the strong interaction betweenthe oxygen vacancies and Pt clusters. Therefore, the long-term stability offormaldehyde gas detection is improved. The results of theoreticalcalculations in this work reveal that the excellent formaldehyde gasdetection of Pt/In2O3-xoriginates from the electron enrichment due to the surface oxygen vacancies and the molecular adsorptionand activation ability of Pt clusters on the surface. The developed Pt/In2O3-xsensor has potential use in the ultraefficient, low-temperature, highly sensitive, and stable detection of indoor formaldehyde at an operating temperature as low as room temperature.