Cobalt Nanoparticles Embedded in N, S Co‐Doped Carbon towards Oxygen Reduction Reaction Derived by in situ Reducing Cobalt Sulfide

Abstract

Herein, a novel electrocatalysts of cobalt nanoparticles embedded in N, S co-doped carbon matrix derived by in situ reducing Co 9 S 8 are designed and prepared successfully through two-calcination methods, and applied for oxygen reduction reaction (ORR). Due to the large surface area and pore volume, richness of defects existing the carbon nanotubes, interaction of S species and N species and special direction of electron transfers between Co and S ions, the earth-abundant and lowcost CoSMe-0.5-800 presents a highly efficient ORR activity and stability. The onset potential, half-wave potential and limiting current density of CoSMe-0.5-800 are 0.95 V, 0.85 V, and 4.31 mA cm À 2 , which are higher than that of commercial Pt/C (0.93 V, 0.83 V, 4.19 mA cm À 2 ). More importantly, the interaction between N and S heteroatoms in system gets revealed, that S resources can help to improve the degree of N doping and raise the ratio of pyridinic N species working as the active site for ORR. With the increase of S resources, electrons that should have been transferred from cobalt to sulfur have moved in the opposite direction, which has a negative effect on ORR active performance. This work shows the potential to design advanced Co-based N, S co-doped catalysts with high electrochemical performance and low cost, which could be applied for fuel cells and other devices.[a] Z.

Catalyst overcoating engineering towards high-performance electrocatalysis

“…Transition-metal-derived N-doped carbon materials are normally produced from the pyrolysis of metal-heteroatomcontaining composites or metal-coordinating complexes. 94,[239][240][241] Dong et al 240 obtained N,S-codoped carbon matrix-coated Co NPs through the in situ reduction of Co 9 S 8 with melamine in the process of carbonization. S species could facilitate N element doping into the carbon matrix with a high richness of defects, which served as the additional active sites for the alkaline ORR catalysis.…”

Synthesis of Co9S8@N, S Co-Doped Porous Carbon Core-Shell Nanocomposite with Highly Coulombic Efficiency in Electrochemical Hydrogen Storage Application

“…The EHS capacity of nanocomposite increases with increasing SSA and decreasing porosity (average pore diameter). 21 As the pore diameter decreases, hydrogen interaction improves, thus increasing hydrogen storage.…”

“…Pyrolysis of biomass and conversion into carbon nanomaterial doped with heteroatoms (such as S and N) as functional groups is an effective treatment for the construction of highly active electrocatalysts and electrodes to energy storage. 21,22 Due to their high porosity structures, natural biomass materials have a great surface for the transport of mass and storage. The synergistic effect of heteroatoms and hybridization with metal compounds can effectively enhance the electrocatalytic conductivity and improve the electrochemical properties.…”

N,S-codoped carbon microporous structures derived from dead ginkgo leaves as efficient oxygen reduction reaction catalysts for Al–air batteries

“…10,27 The peak at 284.6 eV indicates the presence of graphite-like sp 2 hybrid carbon in a two-dimensional honeycomb lattice, suggesting that the majority of carbon atoms are bonded within this structure. 46 The high-resolution O 1s spectrum (Fig. 6b) exhibits three distinct oxygen group components, namely CQO (532.14 eV), O-H (533.74 eV), and C-O-C (535.04 eV).…”

“…41,59 In contrast, high porosity introduces defects and heteroatoms, thereby augmenting the effective active sites and effectively regulating their electronic and chemical properties. 7,46 This carbon structure facilitates the process of oxygen reduction reaction (ORR) by facilitating convenient access of reactants (oxygen molecules) to electrocatalytic sites generated through N,S co-doping. In addition, the high-resolution TEM images presented in Fig.…”