Until now, the selective (hetero)aryl C–H alkylation without the assistance of directing groups or preinstallation of functionalities still remains a highly challenging goal. Herein, by developing acid-resistant multispherical cavity carbon-supported cobalt oxide nanocatalysts (CoOx/MSCC) and a hydrogen transfer-mediated activation mode for nonactivated N-heteroaromatics, we present a direct reductive quinolyl and isoquinolyl β-C–H alkylation with various aldehydes as the alkylating agents. The catalytic transformation features broad substrate scope, good functional tolerance, use of Earth-abundant and reusable cobalt catalysts, and no need for prefunctionalizations, demonstrating that the developed nanocatalysts enable one to directly functionalize inert N-heteroaryl systems that are difficult to realize by organometallic complexes.Keywords: cobalt; heterogeneous catalysis; hydrogen transfer; multispherical cavity carbon; quinolyl β-C−H alkylation;

In this work, nitrogen self-doped porous nanoparticles were synthesized through a low cost and simple method with spiral seaweed as a source of nitrogen and carbon. Transmission electron microscopy (TEM), nitrogen adsorption–desorption, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) analysis showed that nitrogen was successfully doped into the framework of porous nanostructures. The nitrogen self-doped porous nanomaterial featured a high surface area and micro/mesoporous structures. The fabricated nanomaterial was then used as a metal-free catalyst for oxygen reduction reaction (ORR). This catalyst exhibited improved electrocatalytic activity, long-term operation stability, and high CH3OH tolerance for ORR in alkaline fuel cells compared with commercial Pt/C catalysts. The influence of different nitrogen species formed in different atmospheres on ORR activity was further investigated. This study shows that spirulina is a suitable nitrogen and carbon source for various carbon-based materials for the development of metal-free efficient catalysts for applications beyond fuel cells.

In this study, using a template (Pluronic P123) as an in situ carbon source, ordered mesoporous carbons (OMC) were successfully synthesized through directing carbonization of templates. Two key factors in the morphology evolution of mesoporous carbon materials were introduced, one is the tailoring role of micelles by ethanediol, and the other is the dehydrated cross-linking effect by sulfuric acid. Through the two factors, the morphology of as-synthesized ordered mesoporous carbons can be altered from bulks to rods and even to sheets. Transmission electron microscopy (TEM) showed ordered mesoporous carbon rods (OMCR) and ordered mesoporous carbons sheets (OMCS) possessed regular morphology and good mesopore structure. Nitrogen adsorption–desorption analysis confirmed that both OMCR and OMCS had high surface area and uniform mesopore distribution, OMCR had the highest surface area (919 m2 g−1) and OMCS had the biggest pore size (9.11 nm). This study also showed that OMCR and OMCS were good carbon carriers; the size of Pt loading nanoparticles can be decreased to 3 nm and Pt/OMCS especially presents very high Pt dispersion and uniformly smallest Pt nanoparticles (2.49 nm).

High dispersion γ-Fe2O3 combined with Au nanoparticles (denoted as γ-Fe2O3–Au NPs) coated by mesoporous silica spheres (denoted as m-SiO2) were synthesized by a facile one-pot method process. The dispersion of γ-Fe2O3 seed is extremely important to the formation of γ-Fe2O3–Au@m-SiO2 composite, by using a certain amount of neutral β-CD as stabilizing agent, high dispersion γ-Fe2O3 NPs with 16 nm can be prepared. Besides, different number of γ-Fe2O3–Au NPs within composite can be tuned with the addition amount of γ-Fe2O3 seed. TEM images showed the ordered morphology, good dispersion, and uniform particle size of γ-Fe2O3–Au NPs inside composite. Furthermore, XRD, M–H curves and N2 sorption characterization confirmed γ-Fe2O3–Au@m-SiO2 composite possessed good magnetic property, uniform mesopore distribution and high surface area.