Synthesis and improved ethanol sensing performance of CuO/SnO2 based hollow microspheres

A carbon microspheres-templated route was developed to synthesize CuO/SnO2 composites. TEM images exhibit a kind of rough and hollow microspherical morphology with average diameters about 130 nm. All the hollow microspheres are composed of SnO2 and CuO nanoparticles with average diameters about no more than 10 nm. EDX, XPS spectrums indicate the elementary composition of CuO/SnO2 composites and the chemical states of primary elements. The N-2 isotherms of 1 mol % CuO/SnO2 show a type-IV isotherm with a H3 type hysteresis loop. The pore size distribution covers a range of 1 similar to 10 nm and the BET surface area reaches 18.879 m(2)/g. Temperature characteristic, transient response, response/recovery speed, selectivity and long term stability for the detection of five kinds of VOCs (volatile organic compounds) were investigated. The sensing mechanism based on surficial reaction and p-n heterojunction depletion region were discussed in detail.