TiO2 is used as catalyst support. The spherical support (Accu ® Sphere, Saint-Gobain) is used as received from the manufacturer and their tests show a narrow size distribution with diameters of D10 = 0.52 mm and D90=0.58 mm. The catalyst is prepared by impregnation with the excess solvent method. Ruthenium(III) chloride hydrate (38.0-42.0 % Ru basis, Sigma Aldrich), is dissolved in water and placed in a thermostated oil bath and stirred. The TiO2 support is poured into the solution, the mixture is heated to 50 °C, and left until the solvent has evaporated. Afterwards the particles are transferred into an oven and dried at 105 °C to remove residual water. The dry particles are subsequently transferred to a muffle furnace and calcined in static air at up to 200 °C. After the particles are cooled down, they are washed three times with dilute ammonia solution (3 wt.-%) to remove remaining chlorides and afterwards three times with deionized water to remove the ammonia. The particles are again dried in an oven at 105 °C over night and stored in a desiccator until use.