Synthesis of self-assembled hollow spherical Au/SnO2@rGO and its enhanced hydrogen sensing properties to ppb-level

With the rapid development of hydrogen energy, more requirements and challenges have been put forward for the low concentration detection of portable hydrogen sensors. In this work, Au/SnO2@rGO porous ternary nanocomposites with controllable micromorphology were synthesized by a facile one-pot hydrothermal method. The microstructure and morphology of the prepared Au/SnO2@rGO nanocomposites were characterized by corresponding techniques. The effects of different Au doping ratios and different doping noble metal elements on the microstructure were systematically studied. A larger specific surface area of 47.08 m2/g is obtained by the Au/SnO2@rGO nanocomposite, which is twice larger than the 22.80 m2/g of pure SnO2. The response of Au/SnO2@rGO to 200 ppm of hydrogen at 330 °C reached 27.57, which was about 3 times than the 10.06 of PureSnO2. Notably, the response of Au/SnO2@rGO to 500 ppb of hydrogen reached 1.98, while PureSnO2 had almost no response. The coupling effects of Au and rGO achieved a larger specific surface area and faster response/recovery time of the sensor. Especially, an excellent limit of detection (LOD) of 0.377 ppm was fulfilled by the enhanced conductivity. The sensing mechanism was systematically studied through the analysis of microtopography and band structures. Combined with the high stability, favorable linearity response and excellent selectivity of rGO-loaded Au-based nanocomposites, this work may provide a new feasible method and reference for the development of high-performance hydrogen sensing materials.