Hydrogenation CO<sub>2</sub> to Formic Acid over Ru Supported on γ-Al<sub>2</sub>O<sub>3</sub> Nanorods

A series of catalysts made of ruthenium loaded on γ-Al 2 O 3 and γ-Al 2 O 3 nanorods were tested for hydrogenation CO 2 to formic acid. Among these catalysts, the catalyst 2% Ru/Al (n) gave the highest activity for hydrogenation CO 2 reaction with the yield of formic acid up to 13.6 mmol /h. The excellent catalytic activity is related to the highly dispersed ruthenium species on the surface of support and abundant hydroxyl groups of the support. The dispersion of ruthenium species and the hydroxyl groups of supports were studied by characterization of XRD, nitrogen adsorption measurement, TEM, D 2 /exchange and H 2 -TPR in detail. The γ-Al 2 O 3 nanorods lead to the highly dispersed ruthenium species and abundant hydroxyl groups, which appears to be more effective for hydrogenation CO 2 to formic acid.