Influence of nanoparticle size on ethanol gas sensing performance of mesoporous α-Fe2O3 hollow spheres

Mesoporous α-Fe2O3 hollow spheres were synthesized through a heterogeneous nucleation method which incorporates a template for carbon-sphere nucleation. The grain size and grain size distribution of nanoparticles that assemble in hollow spheres could be controlled by the precursor solution concentration of Fe3+. The sensitivity of the samples to ethanol gas was investigated. The results indicated that the gas sensing performance is a function of grain size and grain size distribution, which is related to the concentration of Fe3+. The device sensitivity first increases, then decreases according to grain size. It was found that an average grain size of 15.9 ± 1.4 nm has the highest sensitivity to ethanol gas.