RuO₂·<i>x</i>H₂O Supported on Carbon Nanotubes as a Highly Active Catalyst for Methanol Oxidation

Abstract

Highly dispersed ruthenium oxide clusters were synthesized on carbon nanotubes (CNTs) to form RuO 2 · x H 2 O/CNT catalyst by a homogeneous oxidation precipitation method. Methanol oxidation was carried out on RuO 2 · x H 2 O/CNT at low temperatures for the production of diverse oxygenous products, such as methyl formate (MF) and dimethoxymethane (DMM). Unprecedented conversion rate of methanol, high up to 545 mol MeOH (mol Ru surface ) −1 h −1, was observed at 120 °C. The effect of structural water in RuO 2 domains on the performances of the methanol oxidation reaction was investigated by annealing them in N 2 at elevated temperatures. The dehydration of RuO 2 clusters decreased the oxidation ability and changed the selectivity patterns. It was suggested that the behaviors of RuO 2 during the annealing process may be strongly influenced by the interaction between RuO 2 and CNTs.