Synergistic effect of Ni-NbW with binuclear acidity for the hydrogenolysis of Glycerol

Abstract

In this paper, a modified facile one-pot AcHE method was adopted to prepare the nickel nanoparticles embedded into the tungsten and niobium metal oxides with binuclear acidities. Their physical and chemical properties were characterized by XRD, liquid N2 sorption, Py-IR, NH3-TPD, Raman, H2-TPR, XPS and SEM-EDX and TEM techniques, and their catalytic performances were investigated in the hydrogenolysis of glycerol. The characterization results showed that both nickel nanoparticles can be uniformly doped into the Ni-NbxW10-x samples with ordered mesoporous structures and strong interaction between tungsten and niobium species would be formed resulting in the promotion of acidity amount and intensity. The 10Ni-Nb3W7 sample by synergistic effect has higher catalytic performance in the hydrogenolysis of glycerol than other samples owing to the larger acidities with appropriate ratio of Brønsted to Lewis acidity, whose 1, 3-PDO yield of 28.3% and the molar ratio of 1, 3-PDO to 1, 2-PDO of 2.13 would be obtained. The correlations between the ratio of Brønsted to Lewis acidity and the molar ratio of 1, 3-PDO to 1, 2-PDO and Brønsted acidity and 1, 3-PDO yield can be concluded as y = 2.608x-1.502 (R2=0.9831) and y = 1.035x-31.579 (R2=0.9730), respectively. Compared to the 10Ni/Nb3W7 sample prepared by impregnation method, the 10Ni-Nb3W7 sample shows good stability with slight decrease, where the glycerol conversion of 63.2% and 1,3-PDO selectivity of 42.1% can be obtained even though after repeated use for 6 times. The catalytic performance of 10Ni-Nb3W7 sample was also higher than other previously reported nickel-based catalysts, which can further prove a valuable reference for the preparation of effective catalysts in the glycerol hydrogenolysis with high selective production for 1, 3-PDO.