Sulfur and nitrogen co-doped carbon nanotubes for enhancing electrochemical oxygen reduction activity in acidic and alkaline media

Hierarchical ZnCo2O4@NiCo2O4 Core–Sheath Nanowires: Bifunctionality towards High‐Performance Supercapacitors and the Oxygen‐Reduction Reaction

“…Although Pt-based electrodes have been considered as the most effective electrocatalyst because of their outstanding activity of fast four-electron ORR processes, the broad applications in commercial fuel cells are severelyl imited by their high cost, resource scarcity,weakstability,aswell as their vulnerability to methanola nd CO. [24,25] Therefore, researchers have made much efforts to develop non-noblem etal-based catalyst with comparable ORR activity to Pt-based catalyst. Recently,c arbon materials doped with heteroatoms, such as boron, [26] halogen, [27] nitrogen, [7,28] phosphorus, [29] and their mixtures, [30,31] have proved to be highly active towards ORR, being promising substitutes for Pt-basedc atalysts. Despite these progresses, the activity ands tability of ORRc atalysts are still far from satisfaction for practical applications in fuel cells.…”

The synthesis of carbon nanomaterials using chlorinated hydrocarbons over a Fe-Co/CaCO3 catalyst

“…Modification of CNTs has thus led to the creation of new functional and construction materials. 11 Doping of the carbonaceous materials with non-carbon atoms, such as nitrogen, [12][13][14][15][16][17][18][19] boron, [20][21][22][23][24] sulphur, [25][26][27][28][29] oxygen [30][31][32][33][34][35][36] and halogens 11,[37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55] has been explored over the past two decades. Modification of the carbon surface and electronic properties has also been explored but the effect of chlorine (Cl) on the morphology of carbon nanomaterials is not well established.…”

Carbon-Based Metal-Free Electrocatalysis for Energy Conversion, Energy Storage, and Environmental Protection

“…Subsequently, Li et al demonstrated that few-walled CNTs with the outer wall exfoliated by oxidation and hightemperature reactions with ammonia can act as an ORR electrocatalyst in both acidic and alkaline solutions [149]. N,S-co-doped CNTs (NS-CNTs) were also demonstrated to show enhanced ORR activity compared with CNTs, NCNTs, and SCNTs [150] with a much better durability than that of commercial 20 wt% Pt/C catalysts. Other examples of metalfree electrocatalysts for ORR in acidic electrolytes include N-doped SWCNTs [145], vapor-phase-polymerized PEDOT [152], pyridinic and pyrrolic N-doped graphene prepared by confined polymerization/carbonization within layered montmorillonite [90], graphene/CNT layer-by-layer composites [153], and N,F-co-doped graphite nanofibers [154].…”

“…Whereas the majority of recent studies on carbon nanostructured metal-free electrocatalysts focus on ORR reactions in alkaline electrolytes, fuel cells that operate with acidic electrolytes, particularly polymer electrolyte membrane fuel cells (PEMFC) [14,15], can have a more significant economic impact. Therefore, the development of effective metal-free carbon-based catalysts for acidic electrolytes is important, though still challenging [16,[145][146][147][148][149][150].…”