Novel sensitizer AuxSn modify rGO-SnO2 nanocomposites for enhancing detection of sub-ppm H2

AuxSn intermetallic compound was used for the first time as the novel sensitizer and significantly enhanced the H2 sensing performance of rGO-SnO2 nanocomposites. The AuxSn-rGO-SnO2 nanocomposites were synthesized by growing SnO2 and AuxSn nanoparticles on rGO substrates using a one-pot reflux method. Their gas sensing properties were investigated. The Au/Sn molar ratio had a remarkable effect on the AuxSn crystalline phase and the AuxSn-rGO-SnO2 sensing performance. The 3.0% AuxSn-rGO-SnO2 samples showed the optimal response of 77.3 towards 500 ppm H2 and a limit of detection of 0.18 ppm at 175 °C. Possible sensitization mechanisms of AuxSn were discussed. The work provides a promising AuxSn sensitizer for a metal oxide semiconductor to promote its sensing performance. •AuxSn is used for the first time as the novel sensitizer in gas sensing.•The modification of AuxSn enhances the response of rGO-SnO2 nanocomposites to H2.•AuxSn-rGO-SnO2 exhibited lower operating temperatures than rGO-SnO2.•AuxSn-rGO-SnO2 showed a limit of detection of 0.18 ppm at 175 °C.