Hollow porous zinc cobaltate nanocubes photocatalyst derived from bimetallic zeolitic imidazolate frameworks towards enhanced gaseous toluene degradation

Aiming at promoting the photocatalytic performance of spinel oxides, an efficient method of constructing hollow porous zinc cobaltate (ZnxCo3-xO4) nanocubes was established in this work. Bimetallic zeolitic imidazolate frameworks (ZIFs) were prepared through a facile self-assembly strategy, then hollow ZnxCo3-xO4 nanocubes were obtained by calcining the bimetallic ZIFs precursor. The structural features and optical properties of the ZnxCo3-xO4 nanocubes were comprehensively investigated by a series of characterization techniques. With higher specific surface area (about 100 m(2) g(-1)), enhanced light absorbance in the whole range of 350-800 nm and lowered recombination of photogenerated electron-hole pairs, these hollow nanocubes demonstrated attractive photocatalytic activity in degrading gaseous toluene, superior to traditional stoichiometric ZnCo2O4 nanoparticles. The photocatalytic process and related mechanism of toluene degradation were further investigated with in situ Fourier transform infrared (FTIR) spectroscopy and electron paramagnetic resonance (EPR) techniques. Photo-induced O-center dot(2)- and holes were assigned as main reactive species in the photocatalytic system with hollow ZnxCo3-xO4 nanocubes. (C) 2018 Elsevier Inc. All rights reserved.