Chiang Mai Journal of Science

     Compared to the traditional impregnation catalyst, the Ru single-atom exhibited great advantage in the selective hydrogenation of quinoline. 100% quinoline conversion and 99.67% selectivity to 1,2,3,4-tetrahydro quinoline (THQ-1) were obtained over the 1%-Ru-m/M-MWCNTs catalyst successfully. The characterization results of catalysts, the initial reaction rate, TOF value, activation energy, entropy changes were obtained. There were the larger metal surface area, larger hydrogen uptake quantity, higher metal atom dispersion and easier reduction of Ru species were confirmed for the Ru single-atom catalyst. The hydrogenation rate of quinoline was belonged to the zero order reaction by the different initial reaction rate testing, and the value of TOF reached 164.6 h^-1. The activation energy was low as 58.13 kJ·mol^-1 and the entropy changes was -541.32 J·mol^-1·K^-1 combined experiments and calculations. Good stability, reusability and high selectivity to THQ-1 over the Ru single-atom catalyst may be attributed to no adsorption of the benzene ring, easier dissociation step of H₂, higher resistance to nitrogen-containing heterocycles and no loss of Ru atoms. All these works indicated the great advantage of the Ru single-atom catalyst which could be applied in the industrial utilization of quinoline.