High impact of the reducing agent on palladium nanomaterials: new insights from X-ray photoelectron spectroscopy and oxygen reduction reaction

RSC Advances ◽  
2016 ◽  
Vol 6 (15) ◽  
pp. 12627-12637 ◽  
Author(s):  
Yaovi Holade ◽  
Christine Canaff ◽  
Suzie Poulin ◽  
Têko W. Napporn ◽  
Karine Servat ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Chemical Stability ◽  
Photoelectron Spectroscopy ◽  
Reduction Reaction ◽  
High Impact ◽  
Reducing Agent ◽  
X Ray ◽  
Catalytic Performances

The nature of the reduction agent changes drastically the palladium nanomaterials chemical stability, which subsequently alters earnestly their catalytic performances.

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 Facile Synthesis of the Amorphous Carbon Coated Fe-N-C Nanocatalyst with Efficient Activity for Oxygen Reduction Reaction in Acidic and Alkaline Media

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4551 ◽  
Author(s):  
Linglei Jin ◽  
Baikang Zhu ◽  
Xuesong Wang ◽  
Le Zhang ◽  
Debin Song ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Amorphous Carbon ◽  
Photoelectron Spectroscopy ◽  
Potassium Hydroxide Solution ◽  
Reduction Reaction ◽  
Alkaline Media ◽  
X Ray ◽  
Synthesis Strategy ◽  
Fe Nanoparticles

With the assistance of surfactant, Fe nanoparticles are supported on g-C3N4 nanosheets by a simple one-step calcination strategy. Meanwhile, a layer of amorphous carbon is coated on the surface of Fe nanoparticles during calcination. Transmission electron microscopy (TEM), scanning electron microscope (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma (ICP) were used to characterize the morphology, structure, and composition of the catalysts. By electrochemical evaluate methods, such as linear sweep voltammetry (LSV) and cyclic voltammetry (CV), it can be found that Fe25-N-C-800 (calcinated in 800 °C, Fe loading content is 5.35 wt.%) exhibits excellent oxygen reduction reaction (ORR) activity and selectivity. In 0.1 M KOH (potassium hydroxide solution), compared with the 20 wt.% Pt/C, Fe25-N-C-800 performs larger onset potential (0.925 V versus the reversible hydrogen electrode (RHE)) and half-wave potential (0.864 V vs. RHE) and limits current density (2.90 mA cm−2, at 400 rpm). In 0.1 M HClO4, it also exhibits comparable activity. Furthermore, the Fe25-N-C-800 displays more excellent stability and methanol tolerance than Pt/C. Therefore, due to convenience synthesis strategy and excellent catalytic activity, the Fe25-N-C-800 will adapt to a suitable candidate for non-noble metal ORR catalyst in fuel cells.

scholarly journals Non-precious Melamine/Chitosan Composites for the Oxygen Reduction Reaction: Effect of the Transition Metal

2020 ◽  
Vol 7 ◽  
Author(s):  
B. Aghabarari ◽  
M. V. Martínez-Huerta ◽  
M. C. Capel-Sánchez ◽  
M. J. Lázaro
Keyword(s):  
Transition Metal ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Photoelectron Spectroscopy ◽  
Low Cost ◽  
Reduction Reaction ◽  
X Ray ◽  
Transmission Electron ◽  
Electrode Cell ◽  
C And N

The development of active and low-cost electrocatalysts for the oxygen reduction reaction (ORR) is crucial for the sustainable commercialization of fuel cell technologies. In this study, we have synthetized Me/Mo2C (Me = Fe, Co, Cu)-based composites embedded in N- and P-dual doped carbon by means of inexpensive industrial materials, such as melamine and chitosan, as C and N sources, and the heteropolyacid H3PMo12O40 as P and Mo precursor. The effect of the transition metal (Fe, Co, and Cu) on the ORR in alkaline medium has been investigated. The physicochemical properties of the electrocatalysts were performed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and transmission electron microscopy (TEM). Activity towards ORR was carried out in a three-electrode cell using a ring-disk electrode in 0.1M NaOH. The results obtained clearly show the important role played by each transition metal (Fe, Co, and Cu) in the electrochemical activity. Among them, Fe gives rise to the best performing composite in carrying out the oxygen reduction reaction. The formation Fe3C/Mo2C species embedded in N- and P-dual doped carbon seems to be the determining role in the increase of the ORR performance.

scholarly journals Electrocatalytic Oxygen Reduction Reaction at Silver Nanoparticles (AgNPs) Electrode in Neutral Solution: 5-amino- 2-naphthalene-sulfonic acid (ANS) as a Reducing Agent for AgNPs

2022 ◽  
Author(s):  
Balamurugan Arumugam ◽  
Guru Prasad Kuppuswamy ◽  
S. Yuvaraj
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Sulfonic Acid ◽  
Reduction Reaction ◽  
Reducing Agent ◽  
Simultaneous Formation ◽  
X Ray ◽  
Naphthalene Sulfonic Acid ◽  
Vis Spectroscopy ◽  
Electrocatalytic Oxygen Reduction

Abstract We report electrocatalytic oxygen reduction reaction (ORR) at silver nanoparticle (AgNPs) electrodes. The AgNPs was obtained in a general one-pot synthesis using 5-amino 2-naphthalene-sulfonic acid (ANS) as a reducing agent in aqueous and room-temperature conditions. The simultaneous formation of AgNPs and an oxidation of ANS were monitored by UV-vis spectroscopy. Surface morphology of AgNPs was characterized by transmission electron microscopy, which revealed that AgNPs appeared as a sphere. The average size of AgNPs was found to be 162 nm. Furthermore, the chemical identity of the nanostructures was established using X-ray photoelectron spectroscopy and X-ray diffraction. The prepared AgNPs showed electrocatalytic activity for reduction of oxygen in neutral pH. Rotating disk electrode voltammetry was used to elucidate kinetics of ORR at AgNPs electrode. These results reveal that oxygen reduction reaction at AgNPs-PANS electrode involved direct four electron pathways.

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.

scholarly journals A Platinum Monolayer Core-Shell Catalyst with a Ternary Alloy Nanoparticle Core and Enhanced Stability for the Oxygen Reduction Reaction

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Haoxiong Nan ◽  
Xinlong Tian ◽  
Lijun Yang ◽  
Ting Shu ◽  
Huiyu Song ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Ternary Alloy ◽  
Photoelectron Spectroscopy ◽  
Reduction Reaction ◽  
Core Shell ◽  
X Ray ◽  
The Core ◽  
Platinum Monolayer ◽  
Nanoparticle Core

We synthesize a platinum monolayer core-shell catalyst with a ternary alloy nanoparticle core of Pd, Ir, and Ni. A Pt monolayer is deposited on carbon-supported PdIrNi nanoparticles using an underpotential deposition method, in which a copper monolayer is applied to the ternary nanoparticles; this is followed by the galvanic displacement of Cu with Pt to generate a Pt monolayer on the surface of the core. The core-shell Pd1Ir1Ni2@Pt/C catalyst exhibits excellent oxygen reduction reaction activity, yielding a mass activity significantly higher than that of Pt monolayer catalysts containing PdIr or PdNi nanoparticles as cores and four times higher than that of a commercial Pt/C electrocatalyst. In 0.1 M HClO4, the half-wave potential reaches 0.91 V, about 30 mV higher than that of Pt/C. We verify the structure and composition of the carbon-supported PdIrNi nanoparticles using X-ray powder diffraction, X-ray photoelectron spectroscopy, thermogravimetry, transmission electron microscopy, and energy dispersive X-ray spectrometry, and we perform a stability test that confirms the excellent stability of our core-shell catalyst. We suggest that the porous structure resulting from the dissolution of Ni in the alloy nanoparticles may be the main reason for the catalyst’s enhanced performance.

scholarly journals Synergistic Effects of Active Sites’ Nature and Hydrophilicity on the Oxygen Reduction Reaction Activity of Pt-Free Catalysts

Nanomaterials ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 643 ◽  
Author(s):  
Mariangela Longhi ◽  
Camilla Cova ◽  
Eleonora Pargoletti ◽  
Mauro Coduri ◽  
Saveria Santangelo ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Photoelectron Spectroscopy ◽  
Carbon Nanostructures ◽  
Active Sites ◽  
Active Material ◽  
Reduction Reaction ◽  
X Ray

This work highlights the importance of the hydrophilicity of a catalyst’s active sites on an oxygen reduction reaction (ORR) through an electrochemical and physico-chemical study on catalysts based on nitrogen-modified carbon doped with different metals (Fe, Cu, and a mixture of them). BET, X-ray Powder Diffraction (XRPD), micro-Raman, X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM), Scanning Transmission Electron Microscopy (STEM), and hydrophilicity measurements were performed. All synthesized catalysts are characterized not only by a porous structure, with the porosity distribution centered in the mesoporosity range, but also by the presence of carbon nanostructures. In iron-doped materials, these nanostructures are bamboo-like structures typical of nitrogen carbon nanotubes, which are better organized, in a larger amount, and longer than those in the copper-doped material. Electrochemical ORR results highlight that the presence of iron and nitrogen carbon nanotubes is beneficial to the electroactivity of these materials, but also that the hydrophilicity of the active site is an important parameter affecting electrocatalytic properties. The most active material contains a mixture of Fe and Cu.

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