Cobalt–Nitrogen‐Doped Helical Carbonaceous Nanotubes as a Class of Efficient Electrocatalysts for the Oxygen Reduction Reaction

Abstract

The oxygen reduction reaction (ORR) is of significant importance in the development of fuel cells. Now, cobalt-nitrogen-doped chiral carbonaceous nanotubes (l/d-CCNTs-Co) are presented as efficient electrocatalysts for ORR. The chiral template, N-stearyl-l/d-glutamic acid, induces the self-assembly of well-arranged polypyrrole and the formation of ordered graphene carbon with helical structures at the molecular level after the pyrolysis process. Co was subsequently introduced through the post-synthesis method. The obtained l/d-CCNTs-Co exhibits superior ORR performance, including long-term stability and better methanol tolerance compared to achiral Co-doped carbon materials and commercial Pt/C. DFT calculations demonstrate that the charges on the twisted surface of l/d-CCNTs are widely separated; as a result the Co atoms are more exposed on the chiral CCNTs. This work gives us a new understanding of the effects of helical structures in electrocatalysis.

Nitrogen‐Doped Carbon Nanosheets Encapsulating Cobalt Nanoparticle Hybrids as High‐Performance Bifunctional Electrocatalysts

“…The high resolution TEM (HRTEM) image shows that Co particle in Co@NCNSs‐900 is encapsulated in the carbon shells (Figure S3). The distinct layer distance (0.34 nm) is attributable to the (002) plane of graphite carbon indicating high graphitic degree of the carbon shells . Besides, lattice fringes of Co particle (0.205 nm) can be obtained, ascribing to Co (111) crystallographic planes.…”

Zn−Co−S Colloidal Nanocrystal Clusters as Efficient and Durable Bifunctional Electrocatalysts For Full Water Splitting

“…The Zn−Co−S CNCs shows much more superior HER activity with onset overpotential of 40 mV and delivers 10 mA cm −2 at overpotential of 157 mV. The Zn−Co−S CNCs shows a good HER activity in an alkaline solution due to having more active sites and the large surface area . The quantity of active sites of prepared sample was analyzed by measuring electrochemically active surface area (ECSA).…”

Ultra‐thin Co−Fe Layered Double Hydroxide Hollow Nanocubes for Efficient Electrocatalytic Water Oxidation

“…X‐ray photoelectron spectroscopy (XPS) was conducted to identify the surface chemical composition. The high‐resolution Co 2p XPS spectra of Co 0.5 Fe 0.5 (OH) x nanocubes are spitted into two peaks at 797.3 eV and 781.4 eV, which are assigned to the binding energies of Co 2p 3/2 and Co 2p 1/2 (Figure g–i and S6), indicating that Co 2+ is existence in Co 0.5 Fe 0.5 (OH) x nanocubes (the splitting: 15.9 eV) . For Fe 2p, the binding energies of 711.6 eV and 724.9 eV, whose splitting energy is 13.2 eV, suggest that the oxidation state of iron is primarily Fe 3+ in Co 0.5 Fe 0.5 (OH) x (Figure h).…”