scholarly journals Beyond Nitrogen in the Oxygen Reduction Reaction on Nitrogen-Doped Carbons: A NEXAFS Investigation

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1198
Author(s):  
Eugenia Tanasa ◽  
Florentina Iuliana Maxim ◽  
Tugce Erniyazov ◽  
Matei-Tom Iacob ◽  
Tomáš Skála ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Oxygen Reduction Reaction ◽  
Crystallite Size ◽  
Oxygen Reduction ◽  
Photoelectron Spectroscopy ◽  
Nitrogen Concentration ◽  
Nitrogen Plasma ◽  
Reduction Reaction ◽  
Onset Potential ◽  
Nitrogen Doped

Polymer electrolyte membrane fuel cells require cheap and active electrocatalysts to drive the oxygen reduction reaction. Nitrogen-doped carbons have been extensively studied regarding their oxygen reduction reaction. The work at hand looks beyond the nitrogen chemistry and brings to light the role of oxygen. Nitrogen-doped nanocarbons were obtained by a radio-frequency plasma route at 0, 100, 250, and 350 W. The lateral size of the graphitic domain, determined from Raman spectroscopy, showed that the nitrogen plasma treatment decreased the crystallite size. Synchrotron radiation photoelectron spectroscopy showed a similar nitrogen chemistry, albeit the nitrogen concentration increased with the plasma power. Lateral crystallite size and several nitrogen moieties were plotted against the onset potential determined from oxygen reduction reaction curves. There was no correlation between the electrochemical activity and the sample structure, as determine from Raman and synchrotron radiation photoelectron spectroscopy. Near-edge X-ray absorption fine structure (NEXAFS) was performed to unravel the carbon and nitrogen local structure. A difference analysis of the NEXAFS spectra showed that the oxygen surrounding the pyridinic nitrogen was critical in achieving high onset potentials. The work shows that there were more factors at play, other than carbon organization and nitrogen chemistry.

scholarly journals MOF-Derived CuPt/NC Electrocatalyst for Oxygen Reduction Reaction

Catalysts ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 799 ◽  
Author(s):  
Rehan Anwar ◽  
Naseem Iqbal ◽  
Saadia Hanif ◽  
Tayyaba Noor ◽  
Xuan Shi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Photoelectron Spectroscopy ◽  
Rotating Disk ◽  
Reduction Reaction ◽  
Rotating Disk Electrode ◽  
X Ray ◽  
Onset Potential ◽  
Orr Activity

Metal-organic frameworks (MOFs) have been at the center stage of material science in the recent past because of their structural properties and wide applications in catalysis. MOFs have also been used as hard templates for the preparation of catalysts. In this study, highly active CuPt/NC electrocatalyst was synthesized by pyrolyzing Cu-tpa MOF along with Pt precursor under flowing Ar-H2 atmosphere. The catalyst was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray powder diffraction (XRD). Rotating disk electrode study was performed to determine the oxygen reduction reaction (ORR) activity for CuPt/NC in 0.1 M HClO4 at different revolutions per minute (400, 800, 1200, and 1600) and it was also compared with commercial Pt/C catalyst. Further the ORR performance was evaluated by K-L plots and Tafel slope. CuPt/NC shows excellent ORR performance with onset potential of 0.9 V (vs. RHE), which is comparable with commercial Pt/C. The ORR activity of CuPt/NC is demonstrated as an efficient electrocatalyst for fuel cell.

scholarly journals Nitrogen-Doped Superporous Activated Carbons as Electrocatalysts for the Oxygen Reduction Reaction

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1346 ◽  
Author(s):  
María José Mostazo-López ◽  
David Salinas-Torres ◽  
Ramiro Ruiz-Rosas ◽  
Emilia Morallón ◽  
Diego Cazorla-Amorós
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
High Temperatures ◽  
Photoelectron Spectroscopy ◽  
Activated Carbons ◽  
Inert Atmosphere ◽  
Reduction Reaction ◽  
Treatment Temperature ◽  
Onset Potential ◽  
Nitrogen Functionalization

Nitrogen-containing superporous activated carbons were prepared by chemical polymerization of aniline and nitrogen functionalization by organic routes. The resulting N-doped carbon materials were carbonized at high temperatures (600–800 °C) in inert atmosphere. X-ray Photoelectron Spectroscopy (XPS) revealed that nitrogen amount ranges from 1 to 4 at.% and the nature of the nitrogen groups depends on the treatment temperature. All samples were assessed as electrocatalysts for the oxygen reduction reaction (ORR) in alkaline solution (0.1 M KOH) in order to understand the role of well-developed microporosity as well as the different nitrogen functionalities on the electrocatalytic performance in ORR. It was observed that nitrogen groups generated at high temperatures were highly selective towards the water formation. Among the investigated samples, polyaniline-derived activated carbon carbonized at 800 °C displayed the best performance (onset potential of 0.88 V versus RHE and an electron transfer number of 3.4), which was attributed to the highest concentration of N–C–O sites.

scholarly journals Electrocatalytic Performance of Carbon Supported WO3-Contained Pd-W Nanoalloys for Oxygen Reduction Reaction in Alkaline Media

2018 ◽  
Author(s):  
Nan Cui ◽  
Zengfeng Guo ◽  
Wenpeng Li ◽  
Xun Xu ◽  
Hongxia Zhao ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Photoelectron Spectroscopy ◽  
Reduction Reaction ◽  
Alkaline Media ◽  
Alkaline Electrolyte ◽  
Atom Ratio ◽  
Onset Potential ◽  
Electrocatalytic Performance ◽  
Catalytic Stability

In this paper, we first report that WOx contained nanoalloys exhibit stable electrocatalytic performance in alkaline media, though bulk WO3 are easy to be dissolved in NaOH solutions. Carbon supported oxide-rich Pd-W alloy nanoparticles (PdW/C) with different Pd:W atom ratios were prepared by reduction-oxidation method. Among the catalysts, the oxide-rich Pd0.8W0.2/C (Pd/W = 8:2, atom ratio) exhibits the highest catalytic activity for oxygen reduction reaction. The X-ray photoelectron spectroscopy data shows that ~40% of Pd atoms and ~60% of the W atoms are in their oxides form. The Pd 3d5/2 peaks in oxide-rich Pd-W nanoalloys are positive shift compared with that of Pd/C, which indicates the electronic structure of Pd is affected by the strong interaction between Pd and W/WO3. Compare to Pd/C, the onset potential of oxygen reduction reaction at the oxide-rich Pd0.8W0.2/C is positive shifted. The current density (mA·mg Pd−1) at the oxide-rich Pd0.8W0.2/C is ~1.6 times of that at Pd/C. The oxide-rich Pd0.8W0.2/C also exhibits higher catalytic stability than Pd/C, which demonstrate that it is a prospective candidate for the cathode of fuel cells operated with alkaline electrolyte.

scholarly journals Highly effective Fe-N-C electrocatalysts toward oxygen reduction reaction originated from 2,6-diaminopyridine

2021 ◽  
Author(s):  
Weixiang Yang ◽  
Shuihua Tang ◽  
Qiankuan Huang ◽  
Qian Zhang ◽  
Zhen Tang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Photoelectron Spectroscopy ◽  
Active Sites ◽  
Cost Effective ◽  
Reduction Reaction ◽  
Limiting Current ◽  
X Ray ◽  
Onset Potential

Abstract Fe-N-C electrocatalysts have been intensively studied due to their extraordinary catalytic activity toward oxygen reduction reaction (ORR). Here we prepare a Fe-N-C electrocatalyst through cost-effective and nontoxic precursors of 2,6-diaminopyridine (DAP) and FeCl3, where iron ions react with DAP to formed Fe-Nx species first, followed by polymerization and pyrolysis. X-ray diffraction patterns display no obvious Fe2O3 peaks observed in the catalyst as the nominal content of iron addition is less than 10 wt%. X-ray photoelectron spectroscopy spectra indicate that the catalyst has rich pyridinic nitrogen, graphitic nitrogen and Fe-Nx species, which are considered as active sites for ORR. Therefore the catalyst demonstrates an excellent catalytic activity with an onset potential of about 0.96 V, half-wave potential of about 0.84 V, and a limiting current density of 5.8 mA cm-2, better than commercial Pt/C catalyst in an alkaline medium. Furthermore its stability is also much more excellent than that of Pt/C. This work provides a strategy to synthesize universal M-N-C catalysts.

A nitrogen-doped mesoporous carbon containing an embedded network of carbon nanotubes as a highly efficient catalyst for the oxygen reduction reaction

Nanoscale ◽  
2015 ◽  
Vol 7 (45) ◽  
pp. 19201-19206 ◽  
Author(s):  
Jin-Cheng Li ◽  
Shi-Yong Zhao ◽  
Peng-Xiang Hou ◽  
Ruo-Pian Fang ◽  
Chang Liu ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Mesoporous Carbon ◽  
Reduction Reaction ◽  
Efficient Catalyst ◽  
Onset Potential ◽  
Nitrogen Doped ◽  
Highly Efficient ◽  
Embedded Network

A Fe–N-doped mesoporous carbon embedded with a network of CNTs shows a 59 mV more positive onset potential than Pt/C.

scholarly journals Nitrogen-Doped Reduced Graphene Oxide Supported Pd4.7Ru Nanoparticles Electrocatalyst for Oxygen Reduction Reaction

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2727
Author(s):  
Gil-Ryeong Park ◽  
Seung Geun Jo ◽  
Anuraj Varyambath ◽  
Jeonghyun Kim ◽  
Jung Woo Lee
Keyword(s):  
Graphene Oxide ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Reduced Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Reduction Reaction ◽  
Initial Current ◽  
Nitrogen Doped ◽  
Reduced Graphene ◽  
Pyridinic N

It is imperative to design an inexpensive, active, and durable electrocatalyst in oxygen reduction reaction (ORR) to replace carbon black supported Pt (Pt/CB). In this work, we synthesized Pd4.7Ru nanoparticles on nitrogen-doped reduced graphene oxide (Pd4.7Ru NPs/NrGO) by a facile microwave-assisted method. Nitrogen atoms were introduced into the graphene by thermal reduction with NH3 gas and several nitrogen atoms, such as pyrrolic, graphitic, and pyridinic N, found by X-ray photoelectron spectroscopy. Pyridinic nitrogen atoms acted as efficient particle anchoring sites, making strong bonding with Pd4.7Ru NPs. Additionally, carbon atoms bonding with pyridinic N facilitated the adsorption of O2 as Lewis bases. The uniformly distributed ~2.4 nm of Pd4.7Ru NPs on the NrGO was confirmed by transmission electron microscopy. The optimal composition between Pd and Ru is 4.7:1, reaching −6.33 mA/cm2 at 0.3 VRHE for the best ORR activity among all measured catalysts. Furthermore, accelerated degradation test by electrochemical measurements proved its high durability, maintaining its initial current density up to 98.3% at 0.3 VRHE and 93.7% at 0.75 VRHE, whereas other catalysts remained below 90% at all potentials. These outcomes are considered that the doped nitrogen atoms bond with the NPs stably, and their electron-rich states facilitate the interaction with the reactants on the surface. In conclusion, the catalyst can be applied to the fuel cell system, overcoming the high cost, activity, and durability issues.

scholarly journals Correction: Green synthesis of nitrogen-doped multiporous carbons for oxygen reduction reaction using water-caltrop shells and eggshell waste

RSC Advances ◽  
2021 ◽  
Vol 11 (30) ◽  
pp. 18408-18408
Author(s):  
Chun-Han Hsu ◽  
Zheng-Bang Pan ◽  
Hau-Ting Qu ◽  
Chuan-Ren Chen ◽  
Hong-Ping Lin ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Green Synthesis ◽  
Oxygen Reduction ◽  
Reduction Reaction ◽  
Nitrogen Doped ◽  
Eggshell Waste

Correction for ‘Green synthesis of nitrogen-doped multiporous carbons for oxygen reduction reaction using water-caltrop shells and eggshell waste’ by Chun-Han Hsu et al., RSC Adv., 2021, 11, 15738–15747. DOI: 10.1039/D1RA02100A.

scholarly journals Green synthesis of nitrogen-doped multiporous carbons for oxygen reduction reaction using water-caltrop shells and eggshell waste

RSC Advances ◽  
2021 ◽  
Vol 11 (26) ◽  
pp. 15738-15747
Author(s):  
Chun-Han Hsu ◽  
Zheng-Bang Pan ◽  
Hau-Ting Qu ◽  
Chuan-Ren Chen ◽  
Hong-Ping Lin ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Green Synthesis ◽  
Oxygen Reduction ◽  
Reduction Reaction ◽  
Synthetic Method ◽  
Nitrogen Doped ◽  
Activating Agent ◽  
Eggshell Waste

A green synthetic method is proposed for the preparation of nitrogen-doped multiporous carbons (denoted as N-MPCs) from water-caltrop-shell (WCS) biochar by using eggshell waste as both a nitrogen-dopant and an activating agent.

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