The effect of nitrogen species on the catalytic properties of N-doped graphene

Abstract

The production of effective catalysts in the oxygen reduction reaction (ORR) continues to be a great challenge for scientists. A constant increase in demand for energy storage materials is followed by a proportionate increase in the number of reports on electrocatalyst synthesis. The scientific world focuses on environmentally friendly materials synthesized in accordance with the safest possible. In this work, we developed a facile method of obtaining heavy-metal-free electrode materials that are effective in ORR. Graphene-based catalysts were doped using azodicarbonamide (ADC) as the source of nitrogen, then carbonized at high temperatures in the range of 700–900 °C under inert gas flow. The produced materials were tested as catalysts for ORR, which is the most important reaction for Zn–air batteries and fuel cells. All obtained nitrogen-doped graphene foams showed increased catalytic activity in ORR owing to active sites created by nitrogen functional groups on the graphene surface. This paper shows that carbonization temperature has a significant impact on nitrogen content and that a small percentage of nitrogen may have a positive effect on the catalytic activity of the obtained materials. The number of transferred electrons in ORR was found to range from three to the maximal theoretical value, i.e., four.

Molten Salt‐Assisted Synthesis of Co/N‐Doped Carbon Hybrids for Aqueous‐Phase Aerobic Oxidation of 5‐Hydroxymethylfurfural to 2,5‐Furandicarboxylic Acid

“…The presence of the C−N bond in Co/N−C‐a implies the possibility of rapid electron transfer during the reaction thereby enhancing the catalytic activity of the catalyst. Co−N x and pyridinic N in coordination has been widely reported to be active centers for enhancing oxidation reactions, but only high total N content in the catalyst does not govern the performance of the catalyst; it is rather predominantly dictated by the presence of nitrogen functionalities, which are in close association with the disordered carbon that plays the most crucial role in catalytic reactions [39,45,47,48] …”

Molten salt-mediated synthesis of porous N-doped carbon as an efficient ORR electrocatalyst for zinc–air batteries

“…3b, the peaks at 1350 cm À1 (D-band) and 1600 cm À1 (Gband) represent disorder and defects in carbon materials and I D /I G represents the relative graphitization degree of SZ-NC-T (T indicates different calcination temperature). 30,31 As the temperature increased, I D /I G varied from 0.91 to 1.07, which meant that the carbonization temperature was positively correlated with the degree of graphitization. A higher degree of graphitization can boost the electrical conductivity of the material, thus improving the electrochemical performance of the material.…”

Production of Boron Doped Zinc Oxide Electrode Using Zinc Nitrate Hexahydrate and Effect on Supercapacitor Performance

“…Bu çalışmada saf ZnO'in spesifik kapasitans performansını iyileştirmede bor elementi katkı malzemesi olarak seçilmiştir. Katkılı metal oksitler; sol-jel tekniği [27], hidrotermal yöntem [28], mikrodalga sentez [29], elektrokimyasal biriktirme [30] gibi farklı yöntemlerle sentezlenebilir. Hidrotermal yöntem basit, işlenebilir, düşük maliyetli, düşük sıcaklık ve hızlı sentez gibi avantajlarından dolayı yaygın olarak kullanılan bir yöntemdir [31].…”

“…Functionalised hexagonal 239 boron nitride for energy conversion and storage. Journal of Materials Chemistry A, 8 (29), 14384-14399.…”