Hollow Nanostructures of Ternary Ce_1–xCu_xO₂ for Volatile Organic Compound Sensing

Abstract

An increasing number of traditional nanostructures are being replaced by self-assembled hierarchical nanostructures in terms of their electrochemical, optical, catalytic, and shielding properties. These morphologies exhibit high packing density, tunable porosity, and a large surface area. One of the most effective ways to stabilize hollow nanostructures is to modify the interfacial interactions and subsequent particle assembly that take place at the water-and-oil interface in inverse mini-emulsion. In this study, we present the formation of Ce 1−x Cu x O 2 (0< x < 1.0) hollow structures, which show much higher electrochemical response than either of the end members, viz., CeO 2 or CuO/Cu 2 O. It is established that by controlling the diffusion and reaction kinetics, the dimension of the hollow cavity can be easily tuned. The CeO 2 nanostructures are exposed to different VOC gases, at several temperatures, and various concentrations ranging from 1 to 25 ppm. The best performance is found for formaldehyde (HCHO) detection at an activation temperature of 200 °C. Copper doping helps mitigate the poor conductivity issues associated with CeO 2 . This further opens more avenues for the application of Ce-based oxides in electrochemical devices.