Graphene-Templated Cobalt Nanoparticle Embedded Nitrogen-Doped Carbon Nanotubes for Efficient Visible-Light Photocatalysis

Abstract

Visible-light-assisted photocatalysis for the degradation of organic pollutants has recently become an efficient green approach in the field of environmental pollution abatement. Herein, graphene-templated zeolite-imidazolate framework (ZIF-67) derived, Co nanoparticle embedded, nitrogen-doped carbon nanotubes (G-Co-NCNTs) have been developed as a promising, inexpensive, high-yield photocatalyst to decompose reactive black 5 (RB5) under visible light irradiation. Morphology and structural characterization studies revealed that the growth of NCNTs along with pyridinic N content and the abundance of meso-micropores were greater in G-Co-NCNT than in Co-NCNT itself, suggesting the importance of graphene for in situ growth of ZIF-67 on GO. DRS study reveals that G-Co-NCNT exhibited low optical band gap (∼2.9 eV), assisting in the promotion of photoresponse behavior. The photocatalytic activity of our designed G-Co-NCNT hybrid showed excellent dye degradation ability (98%) after 60 min with a wide range of pH tolerance and promising reusability even after five cycles (93%) under visible light, while Co-NCNT demonstrated only about 62% dye degradation, further implying the importance of graphene and oriented NCNTs for dye degradation. Therefore, the G-Co-NCNT hybrid could be used as an efficient photocatalyst for the remediation of organic pollutants in wastewater.

Imidazolatic-Framework Bimetal Electrocatalysts with a Mixed-Valence Surface Anchored on an rGO Matrix for Oxygen Reduction, Water Splitting, and Dye Degradation

“…Figure 7b reveals a predictable optical band gap energy of NiCo-MOF in the metallic form (ca. eV) that was consistent with those in previous reports, 47 but slightly modified by the addition of the GNS. For the composite electrocatalyst, the absorbance edges changed, leading to a band gap of approximately 2.61 eV.…”

“…Quite the opposite, the electrons in the NiCo-MOF conduction band migrate to a lower Fermi graphene level, resulting in the Schottky barrier on the NiCo-MOF@GNS-700 interface (eq ). Consequently, recombination of the NiCo-MOF electron/hole pair is impeded, and the band gap is narrowed (as evident from UV–vis DRS spectra), promoting the mobility of the charge carrier for RhB degradation. , In addition, the presence of more GNS tuned the electronic structure, favored the adsorption of more RhB on the elevated surface area of the NiCo-MOF@GNS-700 surface, and promoted the mobility of the charge carrier for dye degradation.…”

Hydrolysis of Organophosphorus Agents Catalyzed by Cobalt Nanoparticles Supported on Three-Dimensional Nitrogen-Doped Graphene

“…It has been found that the physical and chemical interactions between Co NPs and their supporting matrices, especially the interactions between Co and O and/or N in the matrices, can dramatically affect the catalytic performance of Co NPs . As a matrix for supporting Co NPs, graphene and their derivatives have attracted a great deal of attention for their unique single-atom layer motif, large specific surface area, and good chemical and physical stabilities . Additionally, the aromatic structure of graphene sheets can adsorb the reactant molecules with aromatic groups, which is beneficial for the selectivity of the catalytic reaction. , Anchored on graphene, Co NPs have shown some promise in water splitting, , ammonia–borane dehydrogenation, and alkyne hydrogenation …”

A comprehensive review on the environmental applications of graphene–carbon nanotube hybrids: recent progress, challenges and prospects

“…In addition to that, its microstructure and catalytic efficiency remain unchanged even after 10 th recycling, signifying exceptional stability. (182). Higher surface area of graphene enabled greater ZIF-67 decoration thereby growing of NCNTs was higher in G/Co/NCNT hybrid compared to Co/NCNT.…”