Electrocatalytic Activity of Lanthanum Chromite-Based Composite Cathode for Ammonia Synthesis from Water and Nitrogen

2021 ◽  
Vol 1160 ◽  
pp. 65-74
Author(s):  
Ibrahim A. Amar ◽  
Mohammed M. Ahwidi
Keyword(s):  
Noble Metal ◽  
Electrocatalytic Activity ◽  
Ammonia Synthesis ◽  
Formation Rate ◽  
Sol Gel ◽  
Composite Cathode ◽  
Perovskite Oxide ◽  
Synthesis Process ◽  
Lanthanum Chromite ◽  
Faradaic Efficiency

The electrocatalytic ammonia synthesis using water (along with nitrogen) as a hydrogen source is proposed as an alternative green and clean technology to the energy-intensive and CO2-emitting process (Haber-Bosch) for ammonia production. Besides, a selective electrocatalyst for ammonia synthesis versus the competing hydrogen evolution remains elusive. This study aims to investigate the electrocatalytic activity of non-noble metal Co and Fe-free perovskite oxide-based composite cathode (La0.75Sr0.25Cr0.5Mn0.5O3-δ-Ce0.8Gd0.18Ca0.02O2-δ) towards ammonia synthesis from H2O and N2. The electrocatalyst was synthesized via a sol-gel process and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Ammonia was successfully with a maximum formation rate of 2.5 × 10-10 mol s-1 cm-2 and Faradaic efficiency of 0.52% at 400 oC and applied voltage of 1.4 V. The results demonstrated that the proposed non-noble metal-based electrocatalyst is a promising material for the carbon-free ammonia synthesis process.

Effects of Doped AE (Ca, Sr) on Synthesis and Structure of Lanthanum Chromite-Based Nano-Powder

2012 ◽  
Vol 602-604 ◽  
pp. 249-253
Author(s):  
Xin De Zhu ◽  
Sheng Li Li ◽  
Jian Hua Zhang ◽  
Qing Ao
Keyword(s):  
Perovskite Phase ◽  
Sol Gel ◽  
Synthesis Temperature ◽  
Lanthanum Chromite ◽  
Second Phase ◽  
X Ray Diffraction ◽  
Maximum Solubility ◽  
Scanning Calorimetry ◽  
Nano Powder ◽  
Transmission Electron

Using sol-gel method, a series of nanocrystalline materials La1-xAExCrO3(AE=Ca, Sr) were synthesized. Difference between Ca- and Sr-doped lanthanum chromites were investigated by carrying out differential scanning calorimetry (DSC), thermogravimetric analysis (TG), X-ray diffraction (XRD) and high resolution transmission electron microscope (HRTEM). It was found that the synthesis temperature (1-xCaxCrO3, and CaCrO4as the second phase (x≥0.2) at the room temperature. LSC is composed of single orthorhombic perovskite phase for x=0.1, while the orthorhombic and rhombohedral perovskite phases coexist for x=0.2, and only rhombohedral perovskite phase for x=0.3. Further studies showed that the maximum solubility of Sr was lower than that of Ca in lanthanum chromite.

Sol-gel synthesis and properties of doped lanthanum chromite nanopowders

2013 ◽  
Vol 49 (9) ◽  
pp. 935-938 ◽  
Author(s):  
A. S. Anokhin ◽  
S. S. Strel’nikova ◽  
N. T. Andrianov ◽  
N. A. Makarov ◽  
D. A. Zhirov ◽  
...  
Keyword(s):  
Sol Gel ◽  
Lanthanum Chromite ◽  
Sol Gel Synthesis

Sol-gel synthesis of lanthanum chromite powder

1997 ◽  
Vol 17 (8) ◽  
pp. 1027-1031 ◽  
Author(s):  
S. Bilger ◽  
G. Blaβ ◽  
R. Förthmann
Keyword(s):  
Sol Gel ◽  
Lanthanum Chromite ◽  
Chromite Powder ◽  
Sol Gel Synthesis

Synthesis of lanthanum chromite using the sol-gel method

1998 ◽  
Vol 55 (5-6) ◽  
pp. 182-185 ◽  
Author(s):  
I. A. Zhigalkina ◽  
T. D. Nikolaeva ◽  
Yu. L. Suponitskii ◽  
B. I. Polyak
Keyword(s):  
Sol Gel ◽  
Lanthanum Chromite ◽  
Gel Method ◽  
Sol Gel Method

TEM visualization of surface replicated acid and base catalyzed sol-gel glasses

1986 ◽  
Vol 44 ◽  
pp. 448-449
Author(s):  
George C. Ruben ◽  
Merrill W. Shafer
Keyword(s):  
Elevated Temperatures ◽  
Sol Gel ◽  
Basic Medium ◽  
Glass Transition Point ◽  
Structural Space ◽  
Acid And Base ◽  
Organometallic Precursors ◽  
New Processing ◽  
Gel Glasses ◽  
Physical Phenomena

Traditionally ceramics have been shaped from powders and densified at temperatures close to their liquid point. New processing methods using various types of sols, gels, and organometallic precursors at low temperature which enable densificatlon at elevated temperatures well below their liquidus, hold the promise of producing ceramics and glasses of controlled and reproducible properties that are highly reliable for electronic, structural, space or medical applications. Ultrastructure processing of silicon alkoxides in acid medium and mixtures of Ludox HS-40 (120Å spheres from DuPont) and Kasil (38% K2O &62% SiO2) in basic medium have been aimed at producing materials with a range of well defined pore sizes (∼20-400Å) to study physical phenomena and materials behavior in well characterized confined geometries. We have studied Pt/C surface replicas of some of these porous sol-gels prepared at temperatures below their glass transition point.

Electron microscopy studies of PZT ferroelectric film capacitor structures

1992 ◽  
Vol 50 (2) ◽  
pp. 1364-1365
Author(s):  
V. Kaushik ◽  
P. Maniar ◽  
J. Olowolafe ◽  
R. Jones ◽  
A. Campbell ◽  
...  
Keyword(s):  
Electric Fields ◽  
Sol Gel ◽  
Ferroelectric Material ◽  
Dielectric Constants ◽  
Dielectric Films ◽  
Lead Zirconium Titanate ◽  
Si Substrate ◽  
Film Capacitor ◽  
Pzt Films ◽  
High Dielectric

Lead zirconium titanate films (Pb (Zr,Ti) O3 or PZT) are being considered for potential application as dielectric films in memory technology due to their high dielectric constants. PZT is a ferroelectric material which shows spontaneous polarizability, reversible under applied electric fields. We report herein some results of TEM studies on thin film capacitor structures containing PZT films with platinum-titanium electrodes.The wafers had a stacked structure consisting of PZT/Pt/Ti/SiO2/Si substrate as shown in Figure 1. Platinum acts as electrode material and titanium is used to overcome the problem of platinum adhesion to the oxide layer. The PZT (0/20/80) films were deposited using a sol-gel method and the structure was annealed at 650°C and 800°C for 30 min in an oxygen ambient. XTEM imaging was done at 200KV with the electron beam parallel to <110> zone axis of silicon.Figure 2 shows the PZT and Pt layers only, since the structure had a tendency to peel off at the Ti-Pt interface during TEM sample preparation.

The crystallization of thin-film ceramics

1992 ◽  
Vol 50 (1) ◽  
pp. 338-339
Author(s):  
J.M. Schwartz ◽  
L.F. Francis ◽  
L.D. Schmidt ◽  
P.S. Schabes-Retchkiman
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Sol Gel ◽  
Processing Route ◽  
Small Areas ◽  
Ceramic Thin Films ◽  
Complex Shapes ◽  
Sol Gel Process ◽  
Ceramic Precursors ◽  
Crystalline Ceramic

Ceramic thin films and coatings are of interest for electrical, optical, magnetic and thermal barrier applications. Critical for improved properties in thin films is the development of specific microstructures during processing. To this end, the sol-gel method is advantageous as a versatile processing route. The sol-gel process involves depositing a solution containing metalorganic or colloidal ceramic precursors onto a substrate and heating the deposited layer to form a crystalline or non-crystalline ceramic coating. This route has several advantages, including the ability to create tailored microstructures and properties, to coat large or small areas, simple or complex shapes, and to more easily prepare multicomponent ceramics. Sol-gel derived coatings are amorphous in the as-deposited state and develop their crystalline structure and microstructure during heat-treatment. We are particularly interested in studying the amorphous to crystalline transformation, because many key features of the microstructure such as grain size and grain size distribution may be linked to this transformation.

Sign in / Sign up

Export Citation Format

Share Document