Ordered Arrays of Bead-Chain-like In2O3 Nanorods and Their Enhanced Sensing Performance for Formaldehyde

Here we present a class of formaldehyde (HCHO) gas sensors with strong responses based on ordered mesostructured In2O3 nanorod arrays, which are synthesized via the nanocastiniz route by directly using the solvent-extracted mesoporous silica as a hard template. By choosing mesoporous silica with different pore sizes and interconnectivity as templates and varying the loading of indium resource on the silica template, we have obtained a series of mesostructured In2O3 nanorod arrays with different textural parameters such as specific surface area, pore size, nanorod diameter, etc. The gas sensing properties for formaldehyde (HCHO) of the In2O3 specimens were examined. The results reveal those mesostructured In2O3 nanorod arrays possess much stronger responses to HCHO even at low concentrations than the bulk In2O3, and larger specific surface areas and pore sizes as well as smaller nanorod diameters would be beneficial for enhancing the sensing properties of In2O3.