General Growth of Carbon Nanotubes for Cerium Redox Reactions in High-Efficiency Redox Flow Batteries

Abstract

<jats:p>Carbon nanotubes (CNTs) possess remarkable mechanical, electrical, thermal, and optical properties that predestine them for numerous potential applications. The conventional chemical vapor deposition (CVD) route for the production of CNTs, however, suffers from costly and complex issues. Herein, we demonstrate a general and high-yield strategy to grow nitrogen-doped CNTs (NCNTs) on three-dimensional (3D) graphite felt (GF) substrates, through a direct thermal pyrolysis process simply using a common tube furnace, instead of the costly and complex CVD method. Specifically, the NCNTs-decorated GF (NCNT-GF) electrode possesses enhanced electrocatalytic performance towards cerium redox reactions, mainly due to the catalytic effect of N atoms doped into NCNTs, and ingenious and hierarchical 3D architecture of the NCNT-GF. As a result, the cell with the NCNT-GF serving as a positive electrode shows the improved energy efficiency with increases of about 53.4% and 43.8% over the pristine GF and the acidly treated GF at a high charge/discharge rate of 30 mA cm<jats:sup>-2</jats:sup>, respectively. Moreover, the as-prepared NCNT catalyst-enhanced electrode is found to be highly robust and should enable a long-term cycle without detectable efficiency loss after 500 cycles. The viable synthetic strategy reported in this study will contribute to the further development of more active heteroatom-doped CNTs for redox flow batteries.</jats:p>

3D Shapeable, Superior Electrically Conductive Cellulose Nanofibers/Ti 3 C 2 T x MXene Aerogels/Epoxy Nanocomposites for Promising EMI Shielding

“…And the cell size decreases with an increase of volume fraction of Ti 3 C 2 T x which is attributed to the increased nucleation density of active seeds that limits the further growth of ice crystals. In Figure 3(i), the characteristic peaks in the Raman spectra of TCTA for D-and G-bands at 1352 and 1584 cm -1 , respectively, are attributed to the residual carbon from decomposed CNF after annealing [43][44][45]. After incorporation of Ti 3 C 2 T x , the newly appeared peak at 200 cm -1 can be assigned to A1g symmetry out-of-plane vibration of Ti atoms, and the peaks at 374 and 583 cm -1 are ascribed to the Eg group vibration and in-plane (shear) modes of Ti, C, and surface functional groups [46].…”

Mechanistic Aspects of the Functionalization of Graphene Oxide with Ethylene Diamine: Implications for Energy Storage Applications

“…However, we observed two lines in the deconvoluted N 1s spectra of EDA/GO. The line at ∼399.5 eV is ascribed to N–H, while the one at ∼401.5 eV is assigned to graphitic nitrogen or quaternary nitrogen (R 4 N + where R can be methyl or hydrogen) . Another anomalous observation was the increase in the carbonyl (CO) groups in the C 1s deconvoluted spectra of EDA/GO relative to GO (Supporting Information, Table S1), which may be due to the formation of amide bonds from the reaction of carboxyl groups with EDA.…”

“…The line at ∼399.5 eV is ascribed to N−H, while the one at ∼401.5 eV is assigned to graphitic nitrogen or quaternary nitrogen (R 4 N + where R can be methyl or hydrogen). 37 Another anomalous observation was the increase in the carbonyl (CO) groups in the C 1s deconvoluted spectra of EDA/GO relative to GO (Supporting Information, Table S1), which may be due to the formation of amide bonds from the reaction of carboxyl groups with EDA. However, the relative percentage increase in carbonyl groups in deconvoluted C 1s spectra does not match the relative percentage decrease in the carboxyl groups of EDA/GO when compared to GO.…”

Direct photoconversion of CO2 to carbon nanotubes for oxygen recycling in extraterrestrial exploration

“…S4 and S5, at the initial reaction stage (2 h), the formation of thin wires/rods is already perceivable on Co3O4 surface, although with limited amount and sparse distribution; at longer reaction times (5, 10 and 30 h) these nanotubes continue to grow in length and density. Raman measurements reveal the presence of characteristic D-band and G-band of graphitic carbon 20,21,22 , indicating the formation of CNTs (Fig. 1a).…”