Enhanced and stable gas sensing performance towards NH3 with AuCu alloy nanoparticles modification over SnO2

The development of high-performance MOS-based sensor is imperative for NH3 monitoring in human breath analysis. Herein, we successfully modified SnO2 with bimetallic AuCu alloy nanoparticles (NPs) through facile reduction method, which showed an enhanced and stable NH3 sensing performance. The sensor based on Au0.5Cu0.3-SnO2 material had optimum selectivity and sensitivity for NH3, with a response value of 5.26 for 100 ppm NH3 at 400 °C, a threefold improvement over pure SnO2 sensor. The experimental results showed that bimetallic AuCu NPs modified materials had an obvious enhancement of chemisorbed oxygen on the interface, which can be attributed to the synergistic effect of Au and Cu, thus improving the consuming process of the target gas. In addition, the sensor also has a certain response to low concentration of NH3 with excellent repeatability and stability during 30 days.