Rationally Constructing A Nano MOF-Derived Ni and CQD Embedded N-Doped Carbon Nanosphere for the Hydrogenation of Petroleum Resin at Low Temperature

Abstract

A key issue in attaining highly efficient supported catalysts for the hydrogenation of unsaturated polymers arises from the entanglement between the number of exposed active sites and the severe internal mass transfer limitation caused by their large molecular size. Hence, an ultrasmall N-doped carbon nanosphere with Ni NPs and CQDs embedded (Ni-CQDs/NCNs) was reasonably constructed by low-temperature (400 °C) pyrolysis of the precursor CQDs@Nano-Ni-ZIFs. As-prepared Ni-CQDs/NCNs exhibited superior catalytic activity to a commercial 10% Pd/C catalyst in petroleum resin hydrogenation under a low temperature of 150 °C, which is 100 and 60 °C lower than that of previously reported Ni- and Pd-based catalysts, respectively. The excellent catalytic activity of Ni-CQDs/NCNs mainly contributes to the following factors: first, its ultrasmall structure (ca. 50 nm) eliminates the internal mass transfer limitation; second, the CQDs and N-doped carbon matrix stabilize the 53.1 wt % high-loading Ni NPs at a small size of 5.6 nm, providing abundant active sites; and third, the electronic regulation of N-doped carbon enhances the intrinsic activity of Ni, which was revealed by the experiments and DFT calculations. Besides, Ni-CQDs/NCNs exhibits long-term stability and appreciable magnetic separation performance, making it a considerable candidate for industrial application. This work not only offers a facile approach to prepare nano MOF-derived catalysts but also gives helpful instruction to the rational design of heterogeneous catalysts for the reaction involving large molecules.

Atom Doping Engineering of Metal/Carbon Catalysts for Biomass Hydrodeoxygenation

“…In addition to triggering defects and active sites in the carbon matrix, the doping of strongly coordinated heteroatoms, such as N and P, can also anchor MNPs as reaction centers. 158 By the DFT calculations results, Wu et al 76 found that the electronic regulation of N-doped carbon enhances the intrinsic activity of Ni in hydrogenation. Specifically, the Ni 6 cluster anchored on carbon (Ni 6 /C) and N-dope carbon (Ni 6 /NC) was designed as calculation modes (Figure 28a, b).…”

“…The zeolite imidazolate framework (ZIF), a promising candidate for the synthesis of metal/heteroatom-doped carbon catalysts, can easily control the doping of heteroatoms and design the morphology of carbon because of the periodic alternation of organic ligands and metal ions. As shown in Figure , N-doped carbons with CQDs and Ni NPs catalysts (Ni-CQDs/NC) were prepared by pyrolysis of CQDs@Nano-Ni-ZIFs precursors, which exhibited excellent catalytic activity of petroleum resin hydrogenation over a commercial Pd/C catalyst . The excellent catalytic performances of the catalysts are mainly attributed to the following aspects: (i) The ultrasmall structure (∼50 nm) improves the efficiency of internal mass transfer.…”

“…Synthesis route of Ni-CQDs/NC. Reproduced with permission from ref . Copyright 2021, American Chemical Society.…”

“…Charge density difference isosurface (side view) of (c) Ni 6 /NC and (d) Ni 6 /C. Reproduced with permission from ref . Copyright 2021, American Chemical Society.…”

“…As shown in Figure 7, N-doped carbons with CQDs and Ni NPs catalysts (Ni-CQDs/NC) were prepared by pyrolysis of CQDs@Nano-Ni-ZIFs precursors, which exhibited excellent catalytic activity of petroleum resin hydrogenation over a commercial Pd/C catalyst. 76 The excellent catalytic performances of the catalysts are mainly attributed to the following aspects: (i) The ultrasmall structure (∼50 nm) improves the efficiency of internal mass transfer. (ii) The N-doped carbon matrix and CQDs stabilize the high-loading Ni NPs with a small size of 5.6 nm, providing an abundance of active sites.…”