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/TiO2 catalyst at room temperature. Au nanoparticles were initially prepared in solution using HAuCl4.3H2O as Au precursor, sodium citrate as stabilizing agent and sodium borohydride as reducing agent. The preformed Au nanoparticles were further supported on TiO2 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 (COPROX reaction). The obtained Au/TiO2 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 CO2 selectivity of 45% were obtained using an O2/CO ratio of 2 (1 vol% CO, λ=4) and 97 vol% H2 in the feed gas stream (GHSV=15,000 mL gcat −1 h−1).