Nitrogen doped carbonaceous materials as platinum free cathode electrocatalysts for oxygen reduction reaction (ORR)

Abstract

Comparison of physicochemical properties and electrocatalytic behavior of different N-doped carbonaceous materials as potential catalysts for oxygen reduction reaction (ORR) was attended. Ball-milling of graphite with melamine and solvothermal treatment of graphite oxide, graphene nanoplatelets (GNP) with ammonia were used as preparation methods. Elemental analysis and N2 physisorption measurements revealed the synthesis of N-doped materials with strongly different morphological parameters. Contact angle measurements proved that all three samples had good wettability properties. According to analysis of XRD data and Raman spectra a higher nitrogen concentration corresponded to a smaller size of crystallites of the N-doped carbonaceous material. Surface total N content determined by XPS and bulk N content assessed by elemental analysis were close, indicating homogenous inclusion of N in all samples. Rotating disc electrode tests showed that these N-doped materials weremuch less active in acidic medium than in an alkaline environment. Although the presence of in-plane N species is regarded to be advantageous for the ORR activity, no particular correlation was found in these systems with any type of N species. According to Koutecky–Levich analysis, both the N-containing carbonaceous materials and the reference Pt/C catalyst displayed a typical one-step, four-electron ORR route. Both ball-milled sample with high N-content but with low SSA and solvothermally synthesized N-GNP with high SSA but low N content showed significant ORR activity. It could be concluded that beside the total N content other parameters such as SSA, pore structure, structural defects, wettability were also essential for achieving high ORR activity.

Hollow Nitrogen-Doped Carbon Spheres with Presiding Graphitic Nitrogen for Oxygen Reduction Reaction

“…3b), the contents of sp 2 -sp 3 and sp 3 characters in both materials are exhibited in Fig. 3c, where the ratios of (sp 2 -sp 3 )/sp 3 for HNCS and HNCS-1000 are 1.07 and 3.11, respectively, indicating more graphitic carbon rings leading to more content of graphitic-N in HNCS-1000 similar to the XRD results. 34 The structure of both materials was also explored with FTIR and the captured spectra are demonstrated in Fig.…”

“…Nitrogen-doped carbon (NC) is one type of the most efficient emerging catalysts for oxygen reduction reaction (ORR), [1][2][3] including nitrogen-doped graphene, 4,5 nitrogen-doped carbon nanotubes, 6,7 metal organic framework (MOF) derived nitrogendoped carbon 8,9 and hollow nitrogen-doped carbon. 10,11 Thereinto, hollow nitrogen-doped carbon materials are considered the most promising because of their low density, good electrocatalytic properties and controllable morphology, especially when synthesized by template assisted method.…”

Electron-induced hydroamination of ethane as compared to ethene: implications for the reaction mechanism

“…Carbonaceous materials are relevant to a wide range of applications including, among others, water treatment, 1 CO 2 capture, [2][3][4][5][6][7][8][9] catalysis, [10][11][12] novel electrode materials, 13 and sensing. 14,15 Their properties can be tuned and enhanced by incorporation of heteroatoms.…”

“…14,15 Their properties can be tuned and enhanced by incorporation of heteroatoms. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] Nitrogen-doping, for instance, increases the binding strength towards diverse molecules such as contaminants, 1 CO 2 , 2,3 or H 2 O. 15 It also changes the electrical conductivity of a carbonaceous material 10,13 or optical properties like the fluorescence efficiency.…”

“…17 Furthermore, the activity of the material towards electrocatalytic reactions of oxygen is enhanced by active nitrogen defect sites 10,11 offering the prospects to develop metal-free catalysts. 12 Due to these promising perspectives, new routes towards incorporation of nitrogen in carbonaceous materials and a profound understanding of how to control these reactions are of utmost interest.…”