Role of Nitrogen Precursor on the Activity Descriptor towards Oxygen Reduction Reaction in Iron‐Based Catalysts

Abstract

Nitrogen-doped carbon nanostructures supported non-precious transition metal/metal oxide electrocatalysts are promising alternative to platinum-based electrocatalysts for oxygen reduction reaction (ORR) of polymer electrolyte membrane fuel cell (PEMFC). In this article, a variety of nitrogen-doped carboniron based electrocatalysts were prepared by pyrolyzing a particular nitrogen-containing precursor compound with iron oxide at various reaction conditions using hydrothermal method. Our experimental data showed that the ratio between nitrogen containing precursor and metal ions plays significant role in determining the performance of ORR. The increase in nitrogen containing active sites is not linearly proportional to the quantity of nitrogenous precursor. Careful investigation by different spectroscopic (e. g. X-ray photoelectron spectroscopy, Raman Spectroscopy) as well as microscopic techniques along with electrochemical studies, we can conclude that-(a) nitrogen precursor in the synthesis process plays significant role in determining the morphology and oxidation state of iron in final catalyst; and (b) the overall electrocatalytic behaviour of Fe-NÀC based electrocatalysts are largely dependent upon the oxidation state and morphology of catalyst.

Dual-Template Construction of Iron–Nitrogen-Codoped Hierarchically Porous Carbon Electrocatalyst for Oxygen Reduction Reaction

“…To investigate the Tafel plot, the J k was obtained by the equation as follows where J k is the kinetic current density; meanwhile, J L and J are the diffusion-limiting current density and the apparent current density, respectively.…”

Facile Generation of a Stable Bi-Functional Mixed Phase Fe3O4/Fe-N4 Electrocatalyst for Rechargeable Zinc-Air Battery

“…S3a, exhibiting the various vibrational modes present in the samples, have been thoroughly discussed in our previous work. 40 It is noteworthy that the intensity ratio (I D /I G ) of the D band (1350 cm −1 ) and the G band (1590 cm −1 ) corresponding to the defect-disorder in the structure and in-plane vibration of sp 2 carbon respectively, considered as an important parameter was observed to be increased for the annealed sample, FeNC-800. The formation of more defective structures post-annealing has been known to enhance the number and catalytic activity of the active sites.…”

“…The synthesis procedure is followed exactly from our previous work. 40,41 For the hydrothermal synthesis of α-Fe 2 O 3 , 10 ml of triethylamine was stirred with 10 ml of 0.86 M FeCl 3 .6 H 2 O solution and then kept at 180 °C for 18 h in an oven. After cooling the autoclave to room temperature, the obtained α-Fe 2 O 3 was reduced and functionalized using glucosamine hydrochloride (GAH) as the precursor for carbon and nitrogen.…”

“…In this study, we emphasize the facile synthesis method to obtain the oxygen bifunctional activity of iron-based doped carbon-supported catalyst FeNC-800, derived from our previous research work. 40 The as-synthesized catalyst (FeNC-800) via hydrothermal method followed by annealing, contains a variety of bifunctional electrocatalytically active Fe sites providing a low potential difference between ORR and OER at the specified potential values (ΔE) and was employed successfully as the bifunctional oxygen electrocatalyst for the cathode of the zinc-air battery. The material possesses good stability and cyclability as compared to the precursor and intermediate samples owing to extensive catalytically active sites, less mass transfer resistance due to its highly porous nature, and higher electrochemically active surface area.…”

Recent Advances in Waste Plastic Transformation into Valuable Platinum‐Group Metal‐Free Electrocatalysts for Oxygen Reduction Reaction

“…Moreover, process parameters such as pyrolysis temperature, atmosphere, heating and cooling rates must be studied and optimized to obtain a controlled and defined morphology and surface chemistry [126,127] . For doping and surface functionalization, the role of precursors choice could be an important research topic [128] . Higher surface area of the electrocatalysts could be achieved using sacrificial templating, chemical activation (wet or dry impregnation) and mechanochemical techniques such as ball milling.…”