Powder XRD analysis and catalysis characterization of ultra-small gold nanoparticles deposited on titania-modified SBA-15

Ultra-small gold nanoparticles (0.8-1 nm) are successfully deposited on titania-modified SBA-15 via a deposition-precipitation method. A comparison of experimental X-ray diffraction (XRD) patterns with theoretical ones shows that gold exists as Au3+ and Au0 in the as-synthesized and reduced catalyst, respectively. The XRD analyses also suggest that Au nanoparticles are more developed along the 〈1 1 1〉 direction forming a raft-type structure. Z-contrast transmission electron microscopy analyses indicate that the ultra-small gold nanoparticles are uniformly dispersed on the surface of the substrate. The material is found to possess high catalytic activity for low-temperature CO oxidation.