Facile synthesis of highly stable and porous Cu2O/CuO cubes with enhanced gas sensing properties

In this work, highly stable and porous Cu2O/CuO cubes have been successfully synthesized by the calcination of the precursor at different temperatures (350 °C, 450 °C and 550 °C). The precursor which consists of cupric oxalate and cubic Cu2O was obtained by a one-step hydrothermal route with the help of ethylene glycol. The chemical composition and structure of the products were confirmed by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. It is found that the cube is composed of nanoparticles with diameters around several dozens of nanometers and the calcination temperature has great influence on the size, the amount of Cu2O and the surface area of the final products. The gas sensing ability of the as-synthesized porous Cu2O/CuO cubes was investigated toward a series of toxic organic molecules, in which the sample calcined at 350 °C exhibits higher sensing response to acetone. The higher sensing response of this sample might be attributed to the heterostructure of CuO and Cu2O and the relatively high surface area.