DABCO Derived Nitrogen-Doped Carbon Nanotubes for Oxygen Reduction Reaction (ORR) and Removal of Hexavalent Chromium from Contaminated Water

Abstract

Though chemically-derived reduced graphene oxide (CDG) from graphite oxide (GO) precursors is a widely practiced procedure for the large-scale production of graphene, the quality and quantity of thus obtained CDG is dependent on the reduction strategy used. In this work, we report an all-solid-state, residue-free, microwave process for the reduction of graphene oxide and subsequent growth of carbon nanotube ‘separators’ from a single precursor, namely DABCO (1,4-diazabicyclo[2.2.2]octane). The utility of our newly developed technique in efficiently and effectively reducing graphene oxide and in growing nitrogen-doped carbon nanotubes via catalysts like palladium and iron into unique mesoporous, 3-D hierarchical carbon nanostructures is demonstrated. The applicability of the thus obtained palladium embedded in Pd@NCNT-rGO nanoarchitectures for the oxygen reduction reaction (ORR) is investigated. When carbon fiber (CF) was used as the substrate, three-dimensional Fe@NCNT-CF were obtained, whose capability as versatile adsorbents for hexavalent chromium ion removal from contaminated waters was also demonstrated.

Coordination Polymer Framework-Derived Ni-N-Doped Carbon Nanotubes for Electro-Oxidation of Urea

“…These eddy-currents lead to Joule heating of the material, and especially in the case of nano-sized magnetic materials, like Ni-CPF, the heating will be intense and instantaneous. This joule heating results in the released nitrogenated hydrocarbons of H 2 NCH 2 CH 2 [ 35 ], which are captured by nickel moieties and result in the formation of nitrogen-doped carbon nanotubes via diffusion of carbon through the Ni particle [ 36 ]. This is reflected in the elemental map shown in Figure 1 f (and its corresponding dark field image ( Figure 1 e)), wherein the nickel moieties in blue are predominantly present on the walls of the carbon nanotubes whereas the nitrogen moieties are on the walls of the ‘compartments’.…”

Heteroatom‐Doped Carbon Nanotube Membranes from Waste Biomass for Photoelectro‐Catalytic Water Purification

“…[13][14][15][16] Carbon nanotubes often show good adsorption performance for dye molecules because of the weak 𝜋-𝜋 interactions between carbon nanotubes and the aromatic rings of the dye molecules. [17] Moreover, due to the property of compact arrangement, regular porous structure, and excellent conductivity of carbon nanotubes, carbon nanotubes can be used to prepare functional composite materials by the combination of carbon nanotubes with materials, such as TiO 2 , [18,19] palladium, iron, [20] Ti/SnO 2 -Sb, [21] SiO 2 . [22] These composite materials often show excellent photocatalytic and/or electrocatalytic performances as a photocatalytic and/or electrocatalytic catalyst, and are thus used in the field of wastewater treatment.…”