Constructing porous ZnO/SnO2 nanocomposites for the detection of methane at low operating temperature

Aimed at detecting methane (CH 4 ) gas at low operating temperature, porous ZnO/SnO 2 nanocomposites were constructed through a simple two-step method. Pure SnO 2 with a diameter of approximately 120 nm was first synthesized via a hydrothermal method, and then a smaller and looser ZnO/SnO 2 composite structure was obtained by introducing the second component ZnO. The CH 4 sensing test results showed that the ZnO/SnO 2 composites exhibited lower optimum operating temperature (OOT) than that of pure SnO 2 . Besides, compared with pure SnO 2 , the ZnO/SnO 2 composite based sensor present higher response to CH 4 , as well as good repeatability, stability and linearity in a certain range of gas concentration. The improved sensitivity can be mainly attributed to the synergistic effect of porous structure and heterojunction formed between ZnO and SnO 2 .