Preparation of Au/TiO2 by a facile method at room temperature for the CO preferential oxidation reaction

Abstract A simple strategy was used to prepare Au/TiO 2 catalyst at room temperature. Au nanoparticles were initially prepared in solution using HAuCl 4 .3H 2 O as Au precursor, sodium citrate as stabilizing agent and sodium borohydride as reducing agent. The preformed Au nanoparticles were further supported on TiO 2 and the resulting solid material was characterized by Energy-dispersive X-ray spectroscopy, X-ray diffraction and Transmission Electron Microscopy and tested for the preferential oxidation of carbon monoxide in hydrogen-rich stream (CO-PROX reaction). The obtained Au/TiO 2 catalyst consisted of Au nanoparticles with an average size of ~ 4 nm and showed excellent catalytic performance in the 20-50 °C low-temperature range. In particular, at 40 °C a CO conversion of 99.5% and CO 2 selectivity of 45% were obtained using an O 2 /CO ratio of 2 (1 vol% CO, λ = 4) and 97 vol% H 2 in the feed gas stream (GHSV = 15,000 mL g cat −1  h −1 ).