Vitamin Derived Nitrogen Doped Carbon Nanotubes for Efficient Oxygen Reduction Reaction and Arsenic Removal from Contaminated Water

Abstract

Nitrogen doped carbon nanotubes (NCNT) that were prepared by simple microwave pyrolysis of Niacin (Vitamin B3) as noble metal free electrocatalyst for oxygen reduction reaction (ORR) is reported. Our newly developed technique has the distinct features of sustainable and widely available niacin as a bi-functional source of both carbon and nitrogen, whereas the iron catalyst is cheap and the fourth most common element in the Earth’s crust. The results of the electrochemical tests show that our newly developed iron impregnated NCNT anchored on reduced graphene substrate (Fe@NCNT-rGO) catalyst exhibit: a positive half-wave potential (E1/2) of 0.75 V vs. RHE (reversible hydrogen electrode), four-electron pathway, and better methanol tolerance when compared to commercial 20% Pt/C. When applied as adsorbent for arsenic removal, our newly discovered NCNT-Fe illustrate the efficient and effective removal of arsenic across a wide range of pH values.

Transforming Waste Poly(Ethylene Terephthalate) into Nitrogen Doped Carbon Nanotubes and Its Utility in Oxygen Reduction Reaction and Bisphenol-A Removal from Contaminated Water

“…Till date, organically modified nano-clays have been the most prevalent catalyst support, the primary reason being the layered structure of nano-clay impedes the fast escape of gases by “tortuous path” and helps in retention of catalyst particles. Graphene, the newest allotrope of carbon, first isolated by Geim and Novosalev [ 26 ], which when combined with metals either as 0-D quantum dots [ 27 ], 1-D nano-particles [ 28 ], 2-D nano-tubes [ 29 ] or 3-D clusters such as nano-flowers [ 29 ] have been reported in applications such as catalysis [ 30 ], energy storage devices [ 31 ], sensors [ 32 ], etc. Of these, graphene-CNT hybrids have proven to perform excellently in energy storage devices such as super-capacitors [ 33 ], electrodes in sodium-ion batteries [ 34 ], catalysts for ORR reactions [ 35 ], etc.…”

Metal Organic Framework Derived MnO2-Carbon Nanotubes for Efficient Oxygen Reduction Reaction and Arsenic Removal from Contaminated Water

“…A similar synthesis procedure as described in Section 2.2 with substitution of graphene oxide dispersion with carbon fiber is used. However, before use the commercially available CFs were washed successively with 10% HCl and DI water to remove any commercial 'sizing' materials and dipped in Mn-H3BTC stock solution for 30 min which were subsequently removed and dried in oven at 70 °C to obtain Mn-H3BTC MOF decorated carbon fibers (representative XRD and SEM in Figures S1 and S2 of Supplementary File, respectively) which all investigated pH values, our MnO2@CNT-CF nanostructures showed comparable adsorption capacity and when compared with our previously reported Fe@CNT-CF [70]. The well dispersed MnO2 nano-particles in open pore hybrid network of carbon nanotubes vertically anchored on carbon fiber substrate increases the active surface area and facilitates for the optimal capture and retention of arsenic moieties.…”

“…In this manuscript we report for the first time the utility of manganese oxide-CNT on carbon fibers as possible adsorbent of arsenic. The rate of adsorption at various concentrations by our novel MnO 2 @CNT-CF adsorbent is plotted in Figure 5 d which shows that at all investigated pH values, our MnO 2 @CNT-CF nanostructures showed comparable adsorption capacity and when compared with our previously reported Fe@CNT-CF [ 70 ]. The well dispersed MnO 2 nano-particles in open pore hybrid network of carbon nanotubes vertically anchored on carbon fiber substrate increases the active surface area and facilitates for the optimal capture and retention of arsenic moieties.…”

Metal Organic Frameworks Derived Fe-N-C Nanostructures as High-Performance Electrodes for Sodium Ion Batteries and Electromagnetic Interference (EMI) Shielding

“…In contrast, the base was substantially narrower and is consistent with observations of O’Byrne et al who reported a similar phenomenon in nitrogen-doped CNT synthesized from nitrogenated precursors [ 22 , 23 ]. HRTEM of the CNT at the tip exhibited in Figure 1 f indicates presence of highly graphitized inner 22–24 walls, whereas the outermost 3–4 walls were comparatively less graphitized, disordered with interstitial defects, which can be attributed to the ‘knock-on effect’ of microwave radiation, which can damage and dislodge a carbon atom from the walls of CNT [ 24 ]. A dark-field TEM image of Figure 1 d and its corresponding iron and nitrogen maps are shown in Figure 1 g,h,i, respectively, wherein the metal nanostructures anchored on rGO and embedded inside the walls of CNT appear brighter, whereas the carbon moieties appear transparent.…”

“…In this context, synthesis of 3DCNS from calcination and pyrolysis of MOF in conjunction with graphene [19], carbon fibers [20], metal nanowires [21], nanoplatelets [22] etc. has been reported.…”