Enhanced HCHO gas sensing properties by Ag-loaded sunflower-like In2O3 hierarchical nanostructures

Nanoscale Ag-loaded sunflower-like In2O3 hierarchical nanostructures are developed for HCHO detection. Such unique architectures are synthesized by an ambient temperature and pressure hydrolysis reaction combined with a subsequent chemical reduction process. Morphology characterizations confirm that homodisperse nanochains assembled by nanoparticles along the same direction are radially linked to a center to construct sunflower-like hierarchical nanostructures. Novel highly porous and branched structure of the 3D hierarchical architectures and the chemical and electronic sensitization effect of Ag nanoparticles endow Ag-loaded In2O3 nanostructures-based sensors with enhanced gas sensing performances in terms of fast response time (0.9 s), recovery time (14 s), high sensitivity and good sensing selectivity for 20 ppm HCHO. A multistage reaction formation mechanism of the sunflower-like hierarchical nanostructures, and a morphology-dependent sensing mechanism are proposed.