Novel α-Fe2O3/BiVO4 heterojunctions for enhancing NO2 sensing properties

Abstract

We report a novel composite of α-Fe2O3/BiVO4 with n-n heterojunctions for the first time and application in detecting low concentration NO2 gas. The flower-like α-Fe2O3 hierarchical nanostructures were prepared by the solvothermal method followed by BiVO4 nanoparticles decorated on α-Fe2O3 surface by metal-organic decomposition to structure the heterojunctions of α-Fe2O3/BiVO4. The structure and morphology of material were characterized and the sensing properties to NO2 were examined. The results show that the α-Fe2O3/BiVO4 composite (atomic ratio of 8:1:1 for Fe: Bi: V) to 2 ppm NO2 exhibits a four times higher response than pristine α-Fe2O3 at 110 °C, excellent selectivity, and long-term stability. The enhanced sensing properties can be attributed to the porous hierarchical structure of composite and the formation of inner electronic field (IEF) caused by n-n heterojunction at interface between α-Fe2O3 and BiVO4.