Enhanced ammonia sensing using Pt-decorated single-crystalline SnO₂ nanowires prepared by sputtering

Ammonia is a well-known toxic and colorless gas that is widely produced in various chemical and biological industries; thus, developing high-performance gas sensors for the detection of NH₃ is essential. Herein, we prepared a high-performance NH₃ gas sensor based on SnO₂ nanowires coated with Pt by the sputtering method and studied the effect of Pt coating on the gas-sensing performance. Single-crystal SnO₂ nanowires were grown by the CVD method, and sputtering was used to control the thickness of the Pt coating layer. We demonstrated that the NH₃ gas-sensing performance of Pt-SnO₂ nanowires was significantly enhanced compared to that of pristine SnO₂ nanowires. The 5 nm Pt-SnO₂ nanowire sensor exhibits a high response (R _a/R _g) of 19.98 toward 500 ppm NH₃ gas, which is a 19-fold enhancement compared with that of the bare SnO₂ nanowires. The sensor exhibited a fast response and recovery with excellent selectivity over the interfering species C₂H₄, H₂, and acetone. We also proposed a mechanism for the enhanced sensitivity of Pt-SnO₂ nanowires toward NH₃.