Single-atom Pt functionalized In2O3 nanocluster for highly selective and sensitive ppb-level isoprene detection at low temperature

Pt SA/ In 2 O 3 -3% sensor exhibited a remarkable response of 1.96 to isoprene with a concentration as low as 50 ppb at 70°C. • Response kinetic models and DFT calculations were employed to clearly elucidate the response kinetic mechanism of Pt SA/ In 2 O 3 sensor towards isoprene at low temperature. • The superior gas sensing performance of Pt SA/ In 2 O 3 sensor is primarily attributed to the synergistic effect of Pt SA functioning as both active reaction sites and binding sites, unique spillover effect and large specific surface area. Various catalysts have been applied to improve the sensing performance of metal oxide semiconductor (MOS) gas sensors, but achieving high response and outstanding selectivity at low working temperature remains an extremely tough challenge for traditional chemiresistive gas sensors (CGSs). Herein, an in-situ annealing approach has been developed to synthesize composite material with Pt single atoms (Pt SAs) anchored on In 2 O 3 substrate for highly sensitive and selective detecting isoprene at low concentrations (50 ppb) under low temperature of 70 °C. Besides, pure In 2 O 3 and Pt nanoparticles (Pt NPs) were utilized as comparisons to further investigate enhanced sensing mechanism with the support of Pt SAs. Experimental and response kinetic model results suggested that Pt SAs can not only serve as active sites to promote the oxidation of isoprene, but also act independently as binding sites to facilitate the adsorption of isoprene on In 2 O 3 surface. Simultaneously, density functional theory (DFT) calculations demonstrate that Pt SA provides a selective adsorption site for isoprene over other gases, thereby facilitating targeted adsorption of isoprene on In 2 O 3 nanoclusters. This study proves the successful anchoring of Pt SAs on In 2 O 3 nanoclusters by utilizing atomic-level interface modulation engineering strategy, providing an attractive strategy for developing CGSs with high response and selectivity at low working temperatures.