CO Oxidation on Au/α-Fe2O3-Hollow Catalysts: General Synthesis and Structural Dependence

Abstract

Gold nanoparticles supported on iron oxides are highly active catalysts for the CO oxidation even at low temperatures, and their activity strongly depends on the nature of the Fe2O3 support. In the present work, we found a facile route to synthesize α-Fe2O3 nanoparticles with a hollow architecture via a hydrothermal–thermal decomposition process without utilization of templates and surfactants. The key of this synthetic strategy is to induce the formation of hole-like surface defects on the β-FeOOH nanorod precursors with relatively small diameters (20–30 nm) and give a suitable temperature gradient to enhance the volume diffusion of such defects during heating. Finally, the hollow structure can be evolved from the growth of the surface defect clusters on the nanorods. For comparison, α-Fe2O3 nanoparticles with other typical morphologies (i.e., spindle, rod, and hollow rod) were also prepared. Au nanoparticles (2–5 nm) were well dispersed on the different α-Fe2O3 supports via a colloid-deposition method. ...