Actiniae‐like carbon nitride (ACN) bundles were synthesized by the pyrolysis of an asymmetric supramolecular precursor prepared from L‐arginine (L‐Arg) and melamine. ACN has adjustable band gaps (2.25 eV–2.75 eV) and hollow microtubes with ultrathin pore walls, which enrich reaction sites, improve visible‐light absorption and enhance charge separation. In the presence of phenylcarbinol, ACN exhibited excellent water‐splitting ability (95.3 μmol h−1) and in the meanwhile phenylcarbinol was selectively oxidized to benzaldehyde (conversion of 90.9 %, selectivity of 99.7 %) under solar irradiation. For the concurrent reactions, 2D isotope labeling, separation, and detection were conducted to confirm that the proton source of released hydrogen is water. The mechanism of water splitting and phenylcarbinol oxidation was also investigated.
A family of two-dimensional salen-type lanthanide complexes was synthesized through a facile solution diffusion method. The two-dimensional lanthanide complexes were characterized by single-crystal X-ray diffraction (SCXRD) and X-ray photoelectron spectroscopy (XPS) analytical techniques. The SCXRD and XPS analyses reveal that the obtained two-dimensional structures are rich in uncoordinated imine (-CH═N-) groups located on the skeleton of the salen-type organic ligand, which retain strong coordination ability with metal ions. On the basis of this unique feature, a highly dispersed CeO-supported Ni catalyst (Ni/CeO-CAS) with highly strong metal-support interaction was first synthesized via a coordination-assisted synthesis (CAS) method, which exhibits a much better catalytic activity in the hydrogenation of nitrobenzene than the traditional Ni/CeO-IWI catalyst prepared by incipient wetness impregnation (IWI). The origin of the improved catalytic activity of Ni/CeO-CAS as well as the role of Ni@Ce-Hsalen was revealed by using diverse characterizations. On the basis of the comparative characterization results, the superior catalytic performance of Ni/CeO-CAS to Ni/CeO-IWI could have resulted from the smaller and highly dispersed Ni nanoparticulates, the intensified Ni-CeO interaction, the enhanced NiO reducibility, and the higher concentration of oxygen vacancies, favoring the H dissociation and adsorption of the nitrobenzene reactant. The Ni/CeO-CAS catalyst also exhibits high catalytic performance for reduction of diverse nitroarenes to their corresponding functionalized arylamines. We anticipated that this coordination-assisted strategy may provide a new way for preparing other highly oxide-supported catalysts with potential applications in various catalytic reactions.
In this work, the unconsolidated carbon-nitridelayer close-wrapped nanodiamond (H-ND) hybrid has been successfully synthesized by a facile two-step approach including the mechanical milling of ND powder and hexamethylenetetramine and the followed pyrolysis of hexamethylenetetramine. The unique microstructure and surface chemistry characteristics of the nanohybrid have been identified by employing diverse characterization techniques including field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), N 2 adsorption desorption (BET), X-ray diffraction (XRD), Raman spectroscopy (Raman), and X-ray photoelectron spectroscopy (XPS) analyses. Benefiting from the intensified synergistic effect between carbon nitride and nanodiamond, the as-synthesized H-ND hybrid carbocatalyst shows remarkably higher catalytic activity for oxidant-and steam-free direct dehydrogenation (DDH) of ethylbenzene than the nanodiamond (ND) and the previously developed mesoporous carbon nitride, which endows it to be a promising candidate for clean and energy-saving synthesis of styrene through DDH of ethylbenzene. Furthermore, this work also opens a new avenue for fabrication of diverse unconsolidated carbon nitride layers close wrapped nanocarbon hybrids with potential applications for diverse transformations owing to the intensified synergistic effect between carbon nitrides and the nanocarbons.
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