Cu x O self-assembled mesoporous microspheres with effective surface oxygen vacancy and their room temperature NO2 gas sensing performance

Abstract

A series of Cu x O self-assembled mesoporous microspheres (SMMs), with different and controlled morphology (virus-like, urchin-like, spherical), were synthesized by facile liquid phase approach. The morphology of the as-prepared Cu x O SMMs was evolved from spherical to virus-like shape by controlling the ratio of DI water in solution. It can also realize the transformation from loose assembly to dense assembly by extending the reaction time. These Cu x O SMMs exhibited good response to NO2 gas at room temperature, benefiting from their 3D self-assembly structure. Among these the resulting virus-like CuxO SNMMs-based sensor exhibits largely enhanced response to 1 ppm NO2 gas at room temperature. The enhanced response of the virus-like Cu2O SMMsbased sensor can be ascribed to the high surface area, hierarchical 3D nanostructures, micropores for effective gas diffusion, the heterojunctions formed between CuO and Cu2O, and the existence of abundant surface oxygen vacancies.