Heteroatom (Nitrogen/Sulfur)-Doped Graphene as an Efficient Electrocatalyst for Oxygen Reduction and Evolution Reactions

Abstract

Carbon nanomaterials are potential materials with their intrinsic structure and property in energy conversion and storage. As the electrocatalysts, graphene is more remarkable in electrochemical reactions. Additionally, heteroatoms doping with metal-free materials can obtain unique structure and demonstrate excellent electrocatalytic performance. In this work, we proposed a facile method to prepare bifunctional electrocatalyst which was constructed by nitrogen, sulfur doped graphene (NSG), which demonstrate superior properties with high activity and excellent durability compared with Pt/C and IrO2 for oxygen reduction (OR) and oxygen evolution (OE) reactions. Accordingly, these phenomena are closely related to the synergistic effect of doping with nitrogen and sulfur by rationally regulating the polarity of carbon in graphene. The current work expands the method towards carbon materials with heteroatom dopants for commercialization in energy-related reactions.

Calcined Co(II)-Triethylenetetramine, Co(II)- Polyaniline-Thiourea as the Cathode Catalyst of Proton Exchanged Membrane Fuel Cell

“…During this study, Co(II) was simply combined with the amino groups of Triethylenetetramine (TETA) or thiourea, saving the trouble of preparing the complicated porphyrin-Co salts. Moreover, more Nitrogen (N) elements can be provided by both TETA and thiourea, the Sulphur (S) element is provided by thiourea readily, and the S-doped compounds are usually prepared with vaporized sulfur through a chemical vapor deposition (CVD) process [ 18 , 19 ].…”

“…Replacing some of the N-atoms by S-atoms will increase the roughness of the formed CoSyC (S-doped co-catalyst) surfaces with the significantly bigger size of the S-atoms compared to the C-atoms [ 17 ]. Besides, there is a synergistic effect between Co-S and the carbon matrix [ 17 , 18 , 19 , 20 , 21 ]. The S-atoms will be added in the form of thiourea, which does not include only S-atoms but carries two amines to provide more N-atoms for the co-catalysts.…”

Graphene and Graphene-Like Materials for Hydrogen Energy

“…Carbon materials doped with heteroatoms themselves are promising nonmetallic electrocatalysts that can be used in electrochemical storage and energy conversion applications [169][170][171][172]. Their operation mechanism is explained by the difference between the electronegativity of the doping heteroatoms and the carbon atoms of the support itself, which leads to a change in the distribution of the atomic charge/spin density on neighboring carbon atoms that act as active sites in the ORR [173].…”

“… (Color online) Schematic representation of the procedure of synthesis of an ORR electrocatalyst in the form of graphene-like plates doped with S and N [ 171 ]. …”

Surface Diels–Alder adducts on multilayer graphene for the generation of edge-enriched single-atom FeN4 sites for ORR and OER electrocatalysis

“…29,30 Furthermore, the pyridinic-N species are responsible for coordinating Fe atoms to generate an FeN 4 bridging structure which, together with the synergistic effect of the graphitic-N active sites, contributes to improve the ORR electrocatalytic activity. [31][32][33][34][35] On the other hand, DFT calculations have conrmed that graphitic-N species created on N-doped graphene showed a low overpotential and were identied as the optimal active sites for the electrocatalytic OER, 36 while the reactivity of the coordinated FeN 4 species in carbon-based structures contributes positively by reducing potential barriers and improving the electrocatalytic OER activity. 37 In principle, high-performance Fe-N/C electrocatalysts should be designed by arranging N and Fe atoms to form optimal FeN 4 sites uniformly dispersed into the graphitic structure.…”