**2.1. Catalyst preparation**

The catalysts were prepared by impregnation method followed by thermal reduction. The following catalysts were prepared: Ru/C, 5% Pd/C, 5%Re/C, 5% Pd-2% Re/C, 1% Ru-6% Re/C, 5% Ru/Al<sup>2</sup> O3 , 5% Ru/TiO<sup>2</sup> , 5% Re/Al<sup>2</sup> O3 , 5% Co/C, 5% Ru-29%Sn/Al<sup>2</sup> O3 , and 5% Ru/MgO.
