Fabrication of methane thermoelectric gas sensor based on 3D porous Pd/Co3O4 catalyst

BACKGROUND At present, much attention has been focused on the development of methane (CH 4 ) sensors due to a series of explosions and fires caused by CH 4 gas leakage. RESULTS Here, a CH 4 thermoelectric gas sensor (TGS) was fabricated by fixing 3D porous palladium/cobalt oxide (Pd/Co 3 O 4 ) catalyst on a commercial thermoelectric module. 3D porous Pd/Co 3 O 4 catalysts were prepared by a co-precipitation and gel-casting method. The pore structure in catalysts could be tailored only by adjusting the gel viscosity during the formation process. The protocol to tune the pore structure is facile and effective for the improvement of the activity of catalysts. By means of various techniques, the catalysts were characterized and then the possible catalytic mechanism was revealed. The CH 4 TGS based on the optimal Pd/Co 3 O 4 catalyst began to respond at 200 °C, following an obvious output voltage (Δ V ) of 5 mV. Enhancing the operating temperature to 240 °C, the value of Δ V reached to 31 mV and exhibited a linear relationship with CH 4 gas concentration. Meanwhile, the CH 4 TGS showed high sensitivity, repeatability and stability. CONCLUSION The easy and effective preparation method presented to prepare 3D porous Pd/Co 3 O 4 catalyst can provide an unique perspective on the development of 3D porous materials with excellent properties. It can be anticipated that the CH 4 TGS based on the 3D porous Pd/Co 3 O 4 catalyst will be a potential candidate for the detection of CH 4 gas in industrial settings. © 2020 Society of Chemical Industry