Enhanced methane sensing property of flower-like SnO2 doped by Pt nanoparticles: A combined experimental and first-principle study

Pt-doped flower-like SnO2 nanocomposites were successfully synthesized by hydrothermal process, followed by a simple thermal reduction method. And, their morphology, composition and structure were thoroughly studied. The gas sensing performance of undoped and Pt-doped SnO2 gas sensors for methane were systematically investigated. Results indicate that Pt-doped SnO2 nanoflowers (NFs) not only significantly improve the sensitivity, but also reduce the optimal operating temperature compared to undoped SnO2 sensors. Moreover, it improves the stability and selectivity of the SnO2 gas sensor. Combined with adsorption energy and density of states of undoped SnO2 and Pt-doped SnO2 supercells for O-2 and CH4 molecules calculated using first principles based on density functional theory (DFT), it is revealed that the excellent methane gas sensing performance of Pt-doped SnO2 sensor is mainly attributed to the chemical sensitization of Pt dopant to methane gas. Simultaneously, the electronic sensitization of the Schottky junction formed between Pt and SnO2, and the unique Pt-doped SnO2 NFs structure is also beneficial for gas sensing performance.