Titania-supported gold nanoparticles as efficient catalysts for the oxidation of cellobiose to organic acids in aqueous medium

Titania-supported gold nanoparticles were prepared by using the deposition-precipitation method, followed by reduction under a hydrogen flow. The catalytic activity of these as-prepared catalysts was explored in the oxidation of cellobiose to gluconic acid with molecular oxygen, and the properties of these catalysts were examined by using XRD, TEM, temperature-programmed desorption of NH₃, energy-dispersive X-ray spectroscopy, UV/Vis, and X-ray photoemission spectroscopy (XPS). The catalyst sample reduced at high temperature demonstrated an excellent catalytic activity in the oxidation of cellobiose. The characterization results revealed the strong metal-support interaction between the gold nanoparticles and titania support. Hydrogen reduction at higher temperatures (usually >600C) plays a vital role in affording a unique interface between gold nanoparticles and titania support surfaces, which thus improves the catalytic activity of gold/titania by fine-tuning both the electronic and structural properties of the gold nanoparticles and titania support.