Ordered mesoporous N-doped carbon supported Ru for selective adsorption and hydrogenation of quinoline

Abstract

Ordered mesoporous N-doped carbon (OMNC) is prepared via a facile nanocasting approach using ethylenediamine (EDA) and carbon tetrachloride (CTC) as precursors, for which the pore structure, N-dopants and basicity are strongly dependent on the pyrolysis temperature (500–800 °C). After supporting 2.5% Ru by incipient wetness impregnation, the imitate interaction of N-dopants with Ru has a strong influence on the activity and selectivity of quinoline hydrogenation, as disclosed by XPS and H2-TPR studies. It is found that Ru/OMNC-700 obtained at 700 °C shows superior substrate adsorption and catalytic activity under mild conditions (40 °C and 1 MPa H2). The turnover frequency (TOF) and activation energy of Ru/OMNC-700 for the hydrogenation of quinoline are 71.0 h−1 and 31.37 kJ/mol. In particular, this catalyst retains 98.3% of the initial catalytic activity after 5 recycles and shows high compatibility with various N-heterocycles with good conversion and high selectivity, attributed to the strong electron donation from OMNC-700 to Ru and the enhanced adsorption of pyridine ring with high selectivity over OMNC-700. This strategy for the preparation of the supported Ru catalysts opens a new possibility of designing highly efficient heterogeneous catalysts in the future.