Porous alpha-Fe2O3 decorated by Au nanoparticles and their enhanced sensor performance.

Porous alpha-Fe(2)O(3) was synthesized by simple calcination of a beta-FeOOH precursor derived from a facile hydrothermal method. In the hydrothermal process, only FeCl(3).6H(2)O was used as the source material and no templates or pore-directing agents were needed. The as-prepared porous alpha-Fe(2)O(3) was further employed as a support for loading Au nanoparticles (AuNPs). Due to the advantages of porous nanostructures (large surface area and facile gas diffusion) and the catalytic capability of AuNPs, the derived AuNP-supported porous alpha-Fe(2)O(3) was further investigated for gas sensor applications using ethanol as a probe molecule. Obtained results showed that the AuNP-supported porous alpha-Fe(2)O(3) exhibited a much higher response in comparison to pure alpha-Fe(2)O(3). The enhanced sensor properties are attributed to the unique porous structures of the alpha-Fe(2)O(3) support and active AuNPs for promoting sensing reactions, as well as the synergic electronic interaction between Au and alpha-Fe(2)O(3). It is expected that noble metals such as Ag, Pt and Pd can also be supported on other porous metal oxide semiconductors to explore superior properties of functional nanomaterials.