Before the pulse chemisorption, about 150 mg of catalyst was reduced at 200 C for 2 h under 30 mL/min of 5% H2/Ar and purged for 1 h under 30 mL/min of Ar. After cooling down to 100 C, the H2 pulses were injected with a loop volume of 0.989 mL. The chemisorption stoichiometry of H/Ru = 1 was used for calculating the Ru dispersion .