Three-Dimensional Nitrogen-Doped Carbon Nanotubes/Graphene Structure Used as a Metal-Free Electrocatalyst for the Oxygen Reduction Reaction

Abstract

A three-dimensional (3D) nitrogen-doped carbon nanotubes/graphene (NCNTs/G) composite was prepared by pyrolysis of pyridine over a graphene-sheet-supported Ni catalyst. The morphology and structure of the NCNTs/G composite was investigated by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and Raman spectroscopy. Tangled NCNTs with lengths of several hundred nanometers are sparsely, but tighly, distributed on graphene sheets, forming quasi-aligned NCNT arrays. The N content in the NCNTs/G measured by X-ray photoelectron spectroscopy is about 6.6 at. %. The NCNTs/G shows a higher activity and selectivity to the oxygen reduction reaction in alkaline electrolyte compared with undoped CNTs/G, as demonstrated by cyclic voltammetry, rotating disk electrode, and rotating ring-disk electrode measurements. The results indicate that the 3D NCNTs/G composite has potential application in fuel cells.

Templated synthesis of nitrogen-doped graphene-like carbon materials using spent montmorillonite

“…Specically, the calculated n values for C800 is 3.78 at À0.6 V, which is higher than that of N-doped 31 graphene and 3D N-CNT/graphene. 39 The higher electron transfer number implies a faster ORR kinetics with a direct fourelectron-transfer reaction pathway on the C800 electrode to directly reduce oxygen to OH À . In terms of the peak potential, onset potential, and electron transfer number, the as-prepared N-doped graphene-like materials exhibited an enhanced electrocatalytic activity toward ORR.…”

Three-Dimensional Heteroatom-Doped Nanocarbon for Metal-Free Oxygen Reduction Electrocatalysis: A Review

“…To restrain the stacking interaction, which may bury active sites for ORR, between 2D heteroatom-doped graphene sheets, researchers tactfully incorporated 1D structured CNTs between graphene sheets [119][120][121][122][123][124]. The resulting CNTs/graphene hybrid exhibited good ORR activity comparable to and/or better than the commercial Pt/C catalysts under alkaline conditions.…”

“…When tested in acidic solution, a comparable ORR onset potential and much better stability than the commercial Pt/C catalyst were also achieved (Figure 10f). To date, carbon nanotube/graphene hybrid structures doped with heteroatom such as N [57,122,124,126,127] and N/S [121,123] have been fabricated by different methods as promising metal-free catalysts for ORR. comparable ORR onset potential and much better stability than the commercial Pt/C catalyst were also achieved (Figure 10f).…”

Three-Dimensional Porous Architectures of Carbon Nanotubes and Graphene Sheets for Energy Applications

“…CNT-graphene hybrid can also simply obtained by dip-coating CNT dispersion on pre-synthesized graphene foam, taking advantage of the strong hydrophobic and pi-pi interactions between CNTs and graphene (Prasad et al, 2014). Fan et al prepared 3D CNT-graphene sandwich structure from catalyst precursor-coated GO sheets (Ma et al, 2011).…”