scholarly journals Ultrafine TaOx/CB Oxygen Reduction Electrocatalyst Operating in Both Acidic and Alkaline Media

Catalysts ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 35
Author(s):  
Jun-Woo Park ◽  
Jeongsuk Seo
Keyword(s):  
Oxygen Reduction ◽  
Annealing Treatment ◽  
Reduction Reaction ◽  
Alkaline Media ◽  
Oxide Nanoparticles ◽  
Potential Region ◽  
Surface Stability ◽  
Onset Potential ◽  
Alkaline Electrolytes ◽  
Acidic And Alkaline Media

The high activity of non-platinum electrocatalysts for oxygen reduction reaction (ORR) in alkaline media is necessary for applications in energy conversion devices such as fuel cells and metal-air batteries. Herein, we present the electrocatalytic activity of TaOx/carbon black (CB) nanoparticles for the ORR in an alkaline atmosphere as well as in an acidic electrolyte. Ultrafine TaOx nanoparticles 1–2 nm in size and uniformly dispersed on CB supports were prepared by potentiostatic electrodeposition in a nonaqueous electrolyte and subsequent annealing treatment in an H2 flow. The TaOx/CB nanoparticles largely catalyzed the ORR with an onset potential of 1.03 VRHE in an O2-saturated 0.1 M KOH solution comparable to that of a commercial Pt/CB catalyst. ORR activity was also observed in 0.1 M H2SO4 solution. According to the rotating ring disk electrode measurement results, the oxide nanoparticles partly produced H2O2 during the ORR in 0.1 M KOH, and the ORR process was dominated by both the two- and four-electron reductions of oxygen in a diffusion-limited potential region. The Tafel slope of −120 mV dec−1 in low and high current densities revealed the surface stability of the oxide nanoparticles during the ORR. Therefore, these results demonstrated that the TaOx/CB nanoparticles were electroactive for the ORR in both acidic and alkaline electrolytes.

scholarly journals Superior FexN electrocatalyst derived from 1,1′-diacetylferrocene for oxygen reduction reaction in alkaline and acidic media

2020 ◽  
Vol 9 (1) ◽  
pp. 843-852
Author(s):  
Hunan Jiang ◽  
Jinyang Li ◽  
Mengni Liang ◽  
Hanpeng Deng ◽  
Zuowan Zhou
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Current Density ◽  
Active Sites ◽  
Reduction Reaction ◽  
Alkaline Media ◽  
Acidic Media ◽  
Onset Potential ◽  
Acidic And Alkaline Media ◽  
The Stability

AbstractAlthough Fe–N/C catalysts have received increasing attention in recent years for oxygen reduction reaction (ORR), it is still challenging to precisely control the active sites during the preparation. Herein, we report FexN@RGO catalysts with the size of 2–6 nm derived from the pyrolysis of graphene oxide and 1,1′-diacetylferrocene as C and Fe precursors under the NH3/Ar atmosphere as N source. The 1,1′-diacetylferrocene transforms to Fe3O4 at 600°C and transforms to Fe3N and Fe2N at 700°C and 800°C, respectively. The as-prepared FexN@RGO catalysts exhibited superior electrocatalytic activities in acidic and alkaline media compared with the commercial 10% Pt/C, in terms of electrochemical surface area, onset potential, half-wave potential, number of electrons transferred, kinetic current density, and exchange current density. In addition, the stability of FGN-8 also outperformed commercial 10% Pt/C after 10000 cycles, which demonstrates the as-prepared FexN@RGO as durable and active ORR catalysts in acidic media.

2D Layered non-precious metal mesoporous electrocatalysts for enhanced oxygen reduction reaction

2017 ◽  
Vol 5 (10) ◽  
pp. 4868-4878 ◽  
Author(s):  
Lili Huo ◽  
Baocang Liu ◽  
Geng Zhang ◽  
Rui Si ◽  
Jian Liu ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Specific Surface ◽  
Oxygen Reduction ◽  
Electrocatalytic Activity ◽  
Precious Metal ◽  
Reduction Reaction ◽  
High Specific Surface Area ◽  
Alkaline Media ◽  
Homogeneous Distribution ◽  
Acidic And Alkaline Media

2D Layered meso-M/N-C/N-G nanocomposites with high specific surface area, homogeneous distribution of ultra-small M-N-C nanoparticles less than 5 nm, and mesopores with a size of ∼3.6 nm exhibit excellent electrocatalytic activity toward oxygen reduction reaction (ORR) in acidic and alkaline media.

scholarly journals Some reflections on the understanding of the oxygen reduction reaction at Pt(111)

2013 ◽  
Vol 4 ◽  
pp. 956-967 ◽  
Author(s):  
Ana M Gómez-Marín ◽  
Ruben Rizo ◽  
Juan M Feliu
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Surface Oxidation ◽  
Reduction Reaction ◽  
Alkaline Media ◽  
Oxidation Reactions ◽  
Vicinal Surfaces ◽  
Cooperative Approach ◽  
Acidic And Alkaline Media ◽  
The Right

The oxygen reduction reaction (ORR) is a pivotal process in electrochemistry. Unfortunately, after decades of intensive research, a fundamental knowledge about its reaction mechanism is still lacking. In this paper, a global and critical view on the most important experimental and theoretical results regarding the ORR on Pt(111) and its vicinal surfaces, in both acidic and alkaline media, is taken. Phenomena such as the ORR surface structure sensitivity and the lack of a reduction current at high potentials are discussed in the light of the surface oxidation and disordering processes and the possible relevance of the hydrogen peroxide reduction and oxidation reactions in the ORR mechanism. The necessity to build precise and realistic reaction models, which are deducted from reliable experimental results that need to be carefully taken under strict working conditions is shown. Therefore, progress in the understanding of this important reaction on a molecular level, and the choice of the right approach for the design of the electrocatalysts for fuel-cell cathodes is only possible through a cooperative approach between theory and experiments.

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.

Comparative Study of the Oxygen Reduction Reaction on Pyrolyzed FePc in Acidic and Alkaline Media

2018 ◽  
Vol 5 (24) ◽  
pp. 3946-3952 ◽  
Author(s):  
Xue Zhang ◽  
Chi Chen ◽  
Jiao Dong ◽  
Rui‐Xiang Wang ◽  
Qiang Wang ◽  
...  
Keyword(s):  
Comparative Study ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Reduction Reaction ◽  
Alkaline Media ◽  
Acidic And Alkaline Media

Facile and scalable synthesis of coal tar-derived, nitrogen and sulfur-codoped carbon nanotubes with superior activity for O2 reduction by employing an evocating agent

2015 ◽  
Vol 3 (45) ◽  
pp. 22723-22729 ◽  
Author(s):  
Ziwu Liu ◽  
Xin Fu ◽  
Xianyong Wei ◽  
Feng Peng
Keyword(s):  
Carbon Nanotubes ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Coal Tar ◽  
Reduction Reaction ◽  
Alkaline Media ◽  
O2 Reduction ◽  
Acidic And Alkaline Media ◽  
Scalable Synthesis

Nitrogen and sulfur-codoped carbon nanotubes were synthesized with coal tar as nitrogen and sulfur precursors by employing the evocating agent of dicyandiamide. Resultant samples exhibited superior activities for the oxygen reduction reaction in both acidic and alkaline media.

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