We report a novel s-tetrazine based covalent organic framework (TZA-COF) and its hybrid nanocomposites with reduced graphene oxide (TZA-COF-rGO) and Co metal to illustrate novel structure-activity relationships in this class of compounds for electrocatalytic oxygen reduction reaction (ORR). The Co-impregnated hybrid composites (TZA-COF-rGO-Co) were further annealed to yield Co-encapsulated nitrogen doped graphitic carbon (Co@NC-600), which exhibited excellent ORR activity comparable to that of the state-of-the art Pt/C in terms of onset potential, E1/2 (half-wave potential), 4e- reduction selectivity and methanol tolerance. Sequential mechanistic analyses of activity enhancement and electron transfer pathways for the ORR, at different stages of controlled catalyst engineering, elucidated the crucial role of active sites and overall catalyst nature in tuning the ORR mechanism. Co@NC-600 also exhibited high oxygen evolution reaction (OER) activity under alkaline conditions which makes it one of the most efficient non-precious metal bifunctional catalysts, capable of catalyzing complex 4e- reduction processes like the ORR and OER.
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http://dx.doi.org/10.1039/d0nr05337f | DOI Listing |
ChemSusChem
July 2022
Xiamen Key Laboratory of Clean and High-valued Applications of Biomass, College of Energy, Xiamen University, Xiamen, 361102, P. R. China.
2,5-Bis(hydroxymethyl)furan (BHMF) as well as furfuryl alcohol (FFA) are considered as highly valuable biomass-derived alcohols resembling aromatic monomers in polymer synthesis. Herein, a series of cobaltic nitrogen-doped carbon (Co-NC) catalysts calcinated at different temperatures were synthesized and tested for the solvent-free hydrogenation of 5-hydroxymethylfurfural (HMF) to prepare BHMF. It was found that the Co-NC catalyst calcinated at 600 °C (Co-NC-600) exhibited a superior catalytic activity in the hydrogenation reaction mainly due to the doping of graphitic N, which probably facilitated the polarization of H to afford H and H .
View Article and Find Full Text PDFNanoscale
November 2020
New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India.
We report a novel s-tetrazine based covalent organic framework (TZA-COF) and its hybrid nanocomposites with reduced graphene oxide (TZA-COF-rGO) and Co metal to illustrate novel structure-activity relationships in this class of compounds for electrocatalytic oxygen reduction reaction (ORR). The Co-impregnated hybrid composites (TZA-COF-rGO-Co) were further annealed to yield Co-encapsulated nitrogen doped graphitic carbon (Co@NC-600), which exhibited excellent ORR activity comparable to that of the state-of-the art Pt/C in terms of onset potential, E1/2 (half-wave potential), 4e- reduction selectivity and methanol tolerance. Sequential mechanistic analyses of activity enhancement and electron transfer pathways for the ORR, at different stages of controlled catalyst engineering, elucidated the crucial role of active sites and overall catalyst nature in tuning the ORR mechanism.
View Article and Find Full Text PDFInorg Chem
September 2020
School of Materials Science and Engineering, Changchun University of Science and Technology, Changchun 130022, People's Republic of China.
2D metal-organic framework (MOFs) can be ideal sacrificial templates for fabricating nanomaterials because of active sites exposed on the surface rather than in pores and channels, often exhibiting improved performance in catalysis applications. In this study, the novel 2D layered cobalt-based MOF [Co(TPT)(fma)(HO)]·3HO () has been constructed by the selection of high N atom content ligands. On this basis, a 2D nitrogen-doped carbon-coated cobalt nanoparticle composite (Co@NC) was prepared by using this MOF as a precursor.
View Article and Find Full Text PDFChemSusChem
December 2018
College of Chemistry and Chemical Engineering, Gansu Provincial Engineering Laboratory for Chemical Catalysis, Laboratory of Special Function Materials and Structure Design of the Ministry of Education, Lanzhou University, Lanzhou, 730000, P. R. China.
Fabrication of non-noble metal-based heterogeneous catalysts by a facile and cost-effective strategy for ecofriendly catalytic transfer hydrogenation (CTH) is of great significance for organic transformations. A cobalt@nitrogen-doped carbon (Co@NC) catalyst was prepared from renewable biomass-derived sucrose, harmless melamine, and earth-abundant Co(AcO) as the precursor materials by hydrothermal treatment and carbonization. Co nanoparticles (NPs) were coated with NC shells and uniformly embedded in the NC framework.
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