Enhanced Oxygen Reduction Stability and Activity by Co and N (or O) Interaction in CoO on N-Doped Carbon Prepared through Spray Pyrolysis

2018 ◽  
Vol 5 (15) ◽  
pp. 2089-2097 ◽  
Author(s):  
In Gyeom Kim ◽  
In Wook Nah ◽  
Sehkyu Park
Keyword(s):  
Spray Pyrolysis ◽  
Oxygen Reduction ◽  
Reduction Stability

scholarly journals Flame Spray Pyrolysis Co3O4/CoO as Highly-Efficient Nanocatalyst for Oxygen Reduction Reaction

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 925
Author(s):  
Loukas Belles ◽  
Constantinos Moularas ◽  
Szymon Smykała ◽  
Yiannis Deligiannakis
Keyword(s):  
Oxygen Reduction Reaction ◽  
Spray Pyrolysis ◽  
Oxygen Reduction ◽  
Reduction Reaction ◽  
Alkaline Media ◽  
Superior Performance ◽  
Cathode Side ◽  
Flame Spray Pyrolysis ◽  
Oxide Surface ◽  
Flame Spray

The oxygen reduction reaction (ORR) is the rate-limiting reaction in the cathode side of fuel cells. In the quest for alternatives to Pt-electrodes as cathodes in ORR, appropriate transition metal oxide-based electrocatalysts are needed. In the present work, we have synthesized Co3O4 and CoO/Co3O4 nanostructures using flame spray pyrolysis (FSP), as electrocatalysts for ORR in acidic and alkaline media. A detailed study of the effect of (Co-oxide)/Pt ratio on ORR efficiency shows that the present FSP-made Co-oxides are able to perform ORR at very low-Pt loading, 0.4% of total metal content. In acid medium, an electrode with (5.2% Pt + 4.8% Co3O4), achieved the highest ORR performance (Jmax = 8.31 mA/cm2, E1/2 = 0.66 V). In alkaline medium, superior performance and stability have been achieved by an electrode with (0.4%Pt + 9.6% (CoO/Co3O4)) with ORR activity (Jmax = 3.5 mA/cm2, E1/2 = 0.08 V). Using XRD, XPS, Raman and TEM data, we discuss the structural and electronic aspects of the FSP-made Co-oxide catalysts in relation to the ORR performance. Cyclic voltammetry data indicate that the ORR process involves active sites associated with Co3+ cations at the cobalt oxide surface. Technology-wise, the present work demonstrates that the developed FSP-protocols, constitutes a novel scalable process for production of co-oxides appropriate for oxygen reduction reaction electrodes.

scholarly journals Structural and Electrochemical Properties of Nesting and Core/Shell Pt/TiO2 Spherical Particles Synthesized by Ultrasonic Spray Pyrolysis

Metals ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 11 ◽  
Author(s):  
Milica G. Košević ◽  
Milana M. Zarić ◽  
Srećko R. Stopić ◽  
Jasmina S. Stevanović ◽  
Thomas E. Weirich ◽  
...  
Keyword(s):  
Spray Pyrolysis ◽  
Oxygen Reduction ◽  
Hollow Spheres ◽  
Ultrasonic Spray Pyrolysis ◽  
Ex Situ ◽  
Spherical Particles ◽  
Core Shell ◽  
Ultrasonic Spray ◽  
Solid Spheres

Pt/TiO2 composites were synthesized by single-step ultrasonic spray pyrolysis (USP) at different temperatures. In an in-situ method, Pt and TiO2 particles were generated from tetra-n-butyl orthotitanate and chloroplatinic acid, and hydrothermally-prepared TiO2 colloidal dispersion served as Pt support in an ex-situ USP approach. USP-synthesized Pt/TiO2 composites were generated in the form of a solid mixture, morphologically organized in nesting huge hollow and small solid spheres, or TiO2 core/Pt shell regular spheroids by in-situ or ex-situ method, respectively. This paper exclusively reports on characteristic mechanisms of the formation of novel two-component solid composites, which are intrinsic from the USP approach and controlled precursor composition. The generation of the two morphological components within the in-situ approach, the hollow spheres and all-solid spheres, was indicated to be caused by characteristic sol-gel/solid phase transition of TiO2. Both the walls of the hollow spheres and the cores of all-solid ones consist of TiO2 matrix populated by 10 nm-sized Pt. On the other hand, spherical, uniformly-sized, Pt particles of a few nanometers in size created a shell uniformly deposited onto TiO2 spheres of ca. 150 nm size. Activities of the prepared samples in an oxygen reduction reaction and combined oxygen reduction and hydrogen evolution reactions were electrochemically tested. The ex-situ synthesized Pt/TiO2 was more active for oxygen reduction and combined oxygen reduction and hydrogen reactions in comparison to the in-situ Pt/TiO2 samples, due to better availability of Pt within a core/shell structure for the reactions.

Rational prediction of multifunctional bilayer single atom catalysts for the hydrogen evolution, oxygen evolution and oxygen reduction reactions

Nanoscale ◽  
2020 ◽  
Vol 12 (39) ◽  
pp. 20413-20424
Author(s):  
Riming Hu ◽  
Yongcheng Li ◽  
Fuhe Wang ◽  
Jiaxiang Shang
Keyword(s):  
Oxygen Reduction ◽  
Hydrogen Evolution ◽  
Oxygen Evolution ◽  
Single Atom ◽  
Reduction Reactions ◽  
Oxygen Reduction Reactions

Bilayer single atom catalysts can serve as promising multifunctional electrocatalysts for the HER, ORR, and OER.

Preparation of TI-1223 and TI-2223 superconducting films by spray pyrolysis

2001 ◽  
Vol 11 (PR11) ◽  
pp. Pr11-157-Pr11-161 ◽  
Author(s):  
S. Phok ◽  
Z. I. Supardi ◽  
A. Sin ◽  
Ph. Galez ◽  
J. L. Jorda ◽  
...  
Keyword(s):  
Spray Pyrolysis ◽  
Superconducting Films
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