In this work, we present a synthesis approach for nitrogen-doped graphene-sheet-like nanostructures via the graphitization of a heteroatom polymer, in particular, polyaniline, under the catalysis of a cobalt species using multiwalled carbon nanotubes (MWNTs) as a supporting template. The graphene-rich composite catalysts (Co-N-MWNTs) exhibit substantially improved activity for oxygen reduction in nonaqueous lithium-ion electrolyte as compared to those of currently used carbon blacks and Pt/carbon catalysts, evidenced by both rotating disk electrode and Li-O(2) battery experiments. The synthesis-structure-activity correlations for the graphene nanostructures were explored by tuning their synthetic chemistry (support, nitrogen precursor, heating temperature, and transition metal type and content) to investigate how the resulting morphology and nitrogen-doping functionalities (e.g., pyridinic, pyrrolic, and quaternary) influence the catalyst activity. In particular, an optimal temperature for heat treatment during synthesis is critical to creating a high-surface-area catalyst with favorable nitrogen doping. The sole Co phase, Co(9)S(8), was present in the catalyst but plays a negligible role in ORR. Nevertheless, the addition of Co species in the synthesis is indispensable for achieving high activity, due to its effects on the final catalyst morphology and structure, including surface area, nitrogen doping, and graphene formation. This new route for the preparation of a nitrogen-doped graphene nanocomposite with carbon nanotube offers synthetic control of morphology and nitrogen functionality and shows promise for applications in nonaqueous oxygen reduction electrocatalysis for Li-O(2) battery cathodes.

The oxidation of CO to CO 2 by metal catalysts has been intensively investigated; for example, gold nanoparticles have exhibited excellent properties. 1 The metal catalysts are often dispersed on a solid support, such as oxide, zeolite, and so on. Exposed to heating during vehicle use, these metal particles trend to agglomerate and grow, which causes their overall surface area to decrease. As a result, catalyst activity deteriorates. 2 These metal catalysts are also very easily poisoned by exposing them to moisture or organic compounds. On the other hand, the newly developed microporous metal-organic polymers (MMOPs) have recently

Cobalt has become increasingly attractive in homogeneous catalysis because of its unique characteristics and outstanding catalytic performance in addition to being cheap and earth-abundant. Hydride transfer processes are involved in a broad range of organic transformations that allow the facile preparation of various useful chemicals and synthetic building blocks. These reactions have continuously received great attention both from academia and industry. In this perspective, we review homogeneous cobalt-catalyzed hydride transfer reactions according to the classified reaction types and provide a comprehensive overview of the design, synthesis, and reactivity of cobalt catalysts, their catalytic applications, and reaction mechanisms.

Over the course of the past 15 years the success story of N-heterocyclic carbene (NHC) compounds in organic, inorganic, and organometallic chemistry has been extended to another dimension. The immobilization of NHC compounds, undergoing continuous diversification, broadens their range of applications and leads to new solutions for challenges in catalytic and synthetic chemistry. This review intends to present a synthetic toolkit for the immobilization of NHC compounds, giving the reader an overview on synthetic techniques and strategies available in the literature. By individually summarizing and assessing the synthetic steps of the immobilization process, a comprehensive picture of the strategies and methodologies for the immobilization of NHC compounds is presented. Furthermore, the characterization of supported NHC compounds is discussed in detail in order to set up necessary criteria for an in-depth analysis of the immobilized derivatives. Finally, the catalytic applications of immobilized NHC compounds are briefly reviewed to illustrate the practical use of this technique for a broad variety of reaction types.