Cellulose assisted combustion synthesis of high surface area Ni-MgO catalysts: Mechanistic studies

2020 ◽  
Vol 221 ◽  
pp. 462-475
Author(s):  
V. Danghyan ◽  
T. Orlova ◽  
S. Roslyakov ◽  
E.E. Wolf ◽  
A.S. Mukasyan
Keyword(s):  
Combustion Synthesis ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Mechanistic Studies

Mechanisms of Combustion Synthesis and Magnetic Response of High-Surface-Area Hexaboride Compounds

2011 ◽  
Vol 3 (4) ◽  
pp. 1093-1100 ◽  
Author(s):  
Raghunath Kanakala ◽  
Roberto Escudero ◽  
Gabriel Rojas-George ◽  
Mohan Ramisetty ◽  
Olivia A. Graeve
Keyword(s):  
Combustion Synthesis ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Magnetic Response

Solution Combustion Synthesis: Role of Oxidant to Fuel Ratio on Powder Properties

2013 ◽  
Vol 757 ◽  
pp. 85-98 ◽  
Author(s):  
L.D. Jadhav ◽  
S.P. Patil ◽  
A.P. Jamale ◽  
A.U. Chavan
Keyword(s):  
Combustion Synthesis ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Solution Combustion Synthesis ◽  
Nano Particles ◽  
Cubic Phase ◽  
Solution Combustion ◽  
Fuel Ratio ◽  
Powder Properties

Solution combustion synthesis technique is one of the novel techniques used to prepare nanoparticles, multi-component ceramic oxides and nanocomposites with properties better than conventionally prepared one and these materials have been used for various applications such as sensors, catalysts, and materials for solid oxide fuel cell (SOFCs). In the present work, the method has been used to prepare nanoparticles of 10 mol% Gd doped ceria (GDC) and Cu and its oxides. The oxidant to fuel (O/F) ratio is found to affect the powder properties and even compositional homogeneity. In glycine-nitrate combustion synthesis of GDC, as revealed by XRD studies, phase pure nanoparticles with crystallite size in the range 9-12nm were obtained for all the O/F ratios. TEM measurements of calcined powder showed hexagonal shaped particles of roughly 20nm size. The exothermicity was increased with the oxidant to fuel ratio resulting in high surface area and soft agglomerates. A slightly lean O/F ratio gives surface area of 73 m2/g and soft agglomerates (D50= 5.34 mm), which eventually results into high sintering density at low temperature. Raman Spectra of GDC showed a sharp and intense peak at 467 cm−1which corresponds to CeO2due to F2gsymmetry of the cubic phase. In combustion synthesis of copper nitrate and citirc acid, the compositional homogenity and phase purity was affected by the oxidant to fuel ratio. The combustion at stoichiometric O/F ratio gives Cu nano particles, lean O/F ratio gives nanoparticles of Cu, CuO and Cu2O and rich ratio gives pure CuO nanoparticles. These nanoparticles have been studied with different characterization techniques like XRD, TG-DTA, SEM, TEM, FT-IR and Raman.

Tenacious Mass Transfer Limitations Drive Catalytic Selectivity during Electrochemical Carbon Dioxide Reduction

2019 ◽  
Author(s):  
Kailun Yang ◽  
Recep Kas ◽  
Wilson A. Smith
Keyword(s):  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Catalyst Layer ◽  
Active Surface ◽  
Active Surface Area ◽  
High Concentration ◽  
Copper Electrodes ◽  
Surface Enhanced ◽  
Local Current

<p>This study evaluated the performance of the commonly used strong buffer electrolytes, i.e. phosphate buffers, during CO<sub>2</sub> electroreduction in neutral pH conditions by using in-situ surface enhanced infrared absorption spectroscopy (SEIRAS). Unfortunately, the buffers break down a lot faster than anticipated which has serious implications on many studies in the literature such as selectivity and kinetic analysis of the electrocatalysts. Increasing electrolyte concentration, surprisingly, did not extend the potential window of the phosphate buffers due to dramatic increase in hydrogen evolution reaction. Even high concentration phosphate buffers (1 M) break down within the potentials (-1 V vs RHE) where hydrocarbons are formed on copper electrodes. We have extended the discussion to high surface area electrodes by evaluating electrodes composed of copper nanowires. We would like highlight that it is not possible to cope with high local current densities on these high surface area electrodes by using high buffer capacity solutions and the CO<sub>2</sub> electrocatalysts are needed to be evaluated by casting thin nanoparticle films onto inert substrates as commonly employed in fuel cell reactions and up to now scarcely employed in CO<sub>2</sub> electroreduction. In addition, we underscore that normalization of the electrocatalytic activity to the electrochemical active surface area is not the ultimate solution due to concentration gradient along the catalyst layer.This will “underestimate” the activity of high surface electrocatalyst and the degree of underestimation will depend on the thickness, porosity and morphology of the catalyst layer. </p> <p> </p>

Sign in / Sign up

Export Citation Format

Share Document