Nanoporous network SnO2 constructed with ultra-small nanoparticles for methane gas sensor

Abstract

Monitoring the concentration of methane (CH4) can effectively protect the environment from the damage of methane emission. The high sensing performances of methane gas sensor still remain a considerable challenge. Herein, to solve problems mentioned above, nanoporous network SnO2 (NN-SnO2) construct with ultra-small nanoparticles, which exhibits excellent gas-sensing performances for methane, are successfully synthesized via a weak acid glucose-assisted hydrothermal synthesis. The NN-SnO2 displays three particular particle morphologies: roundness, oval and polygon, with an average particle size of ~ 9 nm. When evaluated as a sensing material for methane, the NN-SnO2 sensor exhibits ultra-high response (Ra/Rg = 9.80), fast response/recovery times (τres/τrecov= 1 s/3 s) toward 3000 ppm methane at a operating temperature of 420 °C, which are far superior to the vast majority methane semiconducting sensors, and more importantly, it has barely been reported that the sensor based on NN-SnO2 presented such excellent gas-sensing performances for methane. The outstanding response of the NN-SnO2 for methane gas is derived from the unique mesopores nature and small particles sizes of the as-synthesized NN-SnO2, and the charge transfer between the surface of SnO2 nanoparticles and methane gas molecules.