Carbon Nitride as a Nonprecious Catalyst for Electrochemical Oxygen Reduction

Abstract

Nitrogen-doped carbon-based catalysts are increasingly being studied as Pt-free electrodes for oxygen reduction in polymer electrolyte membrane fuel cells. Here, we study the oxygen reduction activity of stoichiometric carbon nitride, which has much higher nitrogen content and is synthesized at lower temperatures, without using ionic or metallic iron. Carbon nitride was studied and characterized via X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, BET specific surface area analysis, and thermogravimetric analysis. Rotating electrode voltammetry in oxygen-saturated sulfuric acid was used to determine the catalytic activity. The onset potential for oxygen reduction by carbon nitride electrodes was 0.69 V (vs NHE) compared to 0.45 V for a carbon black reference electrode. However, the current density was low, possibly due to the low surface area of the material. Blending the carbon nitride with a high surface area carbon black support resulted in a significant improvement in current density and in an increase in onset potential to 0.76 V. The role of surface area was elucidated via cyclic voltammetry. This work confirms that stoichiometric carbon nitride has improved inherent oxygen reduction activity compared to pure carbon, and suggests that Fe coordination sites are not essential for electrochemical oxygen reduction in nitrogen-containing carbon materials.

Linear and nonlinear optical properties for AA and AB stacking of carbon nitride polymorph (C3N4)

“…The g-C 3 N 4 preparation has been described. [6][7][8][9][10][11][12][13][14][15][16][17][18][19] A hypothetical material, C 3 N 4 may have rather smaller bulk modulus than that of diamond as proposed by rst-principles calculations. 20,21 These outcomes have inspired theoretical calculations [22][23][24][25][26] and experimental efforts to synthesize and distinguish this compound.…”

Nitrogen and oxygen-doped metal-free carbon catalysts for chemoselective transfer hydrogenation of nitrobenzene, styrene, and 3-nitrostyrene with hydrazine

“…Table 4 shows again that the catalyst is selective for the production of 2 through the reduction of the nitro group in the reduction of 3-nitrostyrene after considering the contribution of non-catalytic reduction in which the product 1 is produced through the reduction of the vinyl group in a larger selectivity. 18 (69) [b] 45 (21) [b] 37 (10) [b] 2 80 90 67 (24) [b] 16 (72) [b] 43 (17) [b] 41 (11) [b] 3 100 60 69 (35) [b] 23 (50) [b] 37 (25) [b] 40 (25) [b] Reaction conditions: catalyst 10 mg, 3-nitrostyrene 3.8 mmol.…”

Voltammetric Detection of Oxalic Acid by Using Glassy Carbon Electrodes with Covalently Attached Nitrogen-containing Functional Groups

“…[9][10][11] Moreover, the chemical modification of carbon surfaces has been of significant interest in numerous fields, such as electroanalytical chemistry. 12,13 It has recently been found that the reduction potential of oxygen can be significantly moved the positive direction by using a carbon alloy with nitrogen 14 and nitrogen-containing graphite. 15 In particular, it has been revealed by us that nitrogen-containing functional groups, such as an amino group, can easily be introduced to the surfaces of a glassy carbon (GC) electrode by the electrode oxidation of ammonium carbamate.…”