Ultrasmall Palladium Nanoparticles Anchored on N-Doped Nestlike Carbon Nanosheets for Selective Hydrogenation of Quinolines

N-doped nestlike carbon nanosheets (NCNs-Nx) were prepared successfully by a two-step strategy, namely, the in situ self-assembly hydrothermal synthesis using glucose as the carbon source in the presence of magnesium nitrate and sodium carbonate and the controlled nitrogen doping carbonization using urea as the nitrogen source. The performance of the corresponding Pd/NCNs-Nx catalysts was investigated for the selective hydrogenation of quinolines. The characterization of transmission electron microscopy, nitrogen sorption isotherm measurement, powder X-ray diffraction, X-ray photoelectron spectra, temperature-programmed desorption of pyridine and benzene, and the pyridine adsorption experiments showed that the very high catalytic activities and selectivity of the Pd/NCNs-Nx catalysts were related with the high Pd dispersion and the electronic structure of Pd species as well as the adsorption capacity and the adsorption type of quinoline molecule on the catalyst surface.