Synthesis of Ag-doped SnO2 nanoflowers and applications to room temperature high-performance NO2 gas sensing

SnO 2 has attracted much attention in the field of gas sensors due to its unique structure and properties. In this work, SnO 2 nanoflowers doped by Ag structures were prepared by a facile hydrothermal synthesis method. Ag doping not only increases the number of oxygen vacancies in the composite, but also alters the carrier migration behavior and significantly increases the carrier concentration, promoting the electron transport rate. Additionally, Ag doping enhanced the conductivity and catalytic activity of the composite, making it highly selective for NO 2 . At room temperature (RT), Ag-doped SnO 2 sensor exhibit excellent gas-sensitizing properties. At the NO 2 concentration of 100 ppm at RT (25 °C, 25 % RH) the prepared 2 at% Ag-SnO 2 sensor has a response value of 73.0 (R a /R g ), a response time of 1.4 s, and a detection limit as low as 10 ppb. Its long-term stability is up to 90 days. Doping is an effective way to improve gas sensing performance. It solves the disadvantages of low sensitivity and poor selectivity of SnO 2 . • Preparation Ag-doped SnO 2 nanoflower composites with enriched oxygen vacancies. • The response values up to 73.0 for 100 ppm NO 2 enable ppb-level NO 2 response. • Ag doping improves the response by creating lattice defects.