Layer-tunable synthesis of tetragonal Pr-doped SnO2 nanoplates for enhanced sensitive SO2 sensor

Nowadays SnO2 is widely used in manufacturing gas sensors for the detection of toxic and harmful gases such as SO2. However, SnO2 sensor still has the drawbacks of long recovery/response time and low response value. In this experiment, layer-tunable synthesis of tetragonal Pr-doped SnO2 nanoplates are prepared by a feasible hydrothermal method. Observation at SEM reveals that the layer number increases and the interlayer spacing reduces with the increase of doping ratio of Pr (1, 3, 5 mol%). The gas sensing performance show that the three layer tetragonal structure of 1 mol % Pr-doped SnO2 sample with the extended interlayer spacing exhibits outstanding gas sensing performance to 5 ppm SO2 gas at 300℃, including excellent gas response (Ra/Rg = 2.4), fast gas adsorption and desorption equilibrium (15 s/16 s). This work reveals the significance of the layer number and interlayer spacing on the gas sensing characteristics, and the strategy of Pr dopant will promote the widespread application of SnO2 nanomaterials in SO2 gas sensors to figure out severe environmental problems.