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.

Synthesis of Ammonia Directly from Air and Water via a Single-Chamber Reactor Using Lanthanum Chromite-Based Composite as an Electrocatalyst

2021 ◽  
Vol 32 ◽  
pp. 35-44
Author(s):  
Ibrahim A. Amar ◽  
Mohammed M. Ahwidi
Keyword(s):  
Noble Metal ◽  
Ammonia Synthesis ◽  
Direct Synthesis ◽  
Formation Rate ◽  
Lanthanum Chromite ◽  
Ammonia Production ◽  
Faradaic Efficiency ◽  
Single Chamber ◽  
Promising Technology ◽  
Ammonia Formation

Carbon-free electrosynthesis of ammonia using water (H2 source) and air (N2 source) is promising technology to reduce the global CO2 emission resulting from the industrial ammonia production process (Haber-Bosch). In this study, electrocatalysis activity of non-noble metal perovskite-based catalyst (La0.75Sr0.25Cr0.5Fe0.5O3-δ-Ce0.8Gd0.18Ca0.02O2-δ, LSCrF-CGDC) for ammonia synthesis directly from air and water was explored. Ammonia was successfully from wet air (3%H2O) synthesized in a single-chamber type reactor. The highest ammonia formation rate and Faradaic efficiency of about 1.94×10-11 mol s-1 cm-2 and 2.01% were achieved at 375 oC and 1.2 V, respectively. The observed ammonia formation rate is higher than reported for an expensive noble metal-based catalyst (Ru/MgO). The obtained results indicated that the direct synthesis of ammonia from air and water is a promising technology for green and sustainable ammonia synthesis.

Electron Donation by Low-Crystalline Ba-La-Ce Oxygen-Deficient Composite Oxide Accumulating on Ru Nanoparticles for Ammonia Synthesis under Mild Conditions

2019 ◽  
Author(s):  
Katsutoshi Sato ◽  
Shin-ichiro Miyahara ◽  
Yuta Ogura ◽  
Kotoko Tsujimaru ◽  
Yuichiro Wada ◽  
...  
Keyword(s):  
Ammonia Synthesis ◽  
Bond Cleavage ◽  
Synthesis Process ◽  
Strong Electron ◽  
Mild Conditions ◽  
Ru Nanoparticles ◽  
Rate Determining Step ◽  
Highly Active ◽  
Composite Oxides ◽  
Low Crystalline

<p>To mitigate global problems related to energy and global warming, it is helpful to develop an ammonia synthesis process using catalysts that are highly active under mild conditions. Here we show that the ammonia synthesis activity of Ru/Ba/LaCeO<i><sub>x</sub></i> pre-reduced at 700 °C is the highest reported among oxide-supported Ru catalysts. Our results indicate that low crystalline oxygen-deficient composite oxides, which include Ba<sup>2+</sup>, Ce<sup>3+</sup> and La<sup>3+</sup>, with strong electron-donating ability, accumulate on Ru particles and thus promote N≡N bond cleavage, which is the rate determining step for ammonia synthesis.</p>

Electron Donation by Low-Crystalline Ba-La-Ce Oxygen-Deficient Composite Oxide Accumulating on Ru Nanoparticles for Ammonia Synthesis under Mild Conditions

2019 ◽  
Author(s):  
Katsutoshi Sato ◽  
Shin-ichiro Miyahara ◽  
Yuta Ogura ◽  
Kotoko Tsujimaru ◽  
Yuichiro Wada ◽  
...  
Keyword(s):  
Ammonia Synthesis ◽  
Bond Cleavage ◽  
Synthesis Process ◽  
Strong Electron ◽  
Mild Conditions ◽  
Ru Nanoparticles ◽  
Rate Determining Step ◽  
Highly Active ◽  
Composite Oxides ◽  
Low Crystalline

<p>To mitigate global problems related to energy and global warming, it is helpful to develop an ammonia synthesis process using catalysts that are highly active under mild conditions. Here we show that the ammonia synthesis activity of Ru/Ba/LaCeO<i><sub>x</sub></i> pre-reduced at 700 °C is the highest reported among oxide-supported Ru catalysts. Our results indicate that low crystalline oxygen-deficient composite oxides, which include Ba<sup>2+</sup>, Ce<sup>3+</sup> and La<sup>3+</sup>, with strong electron-donating ability, accumulate on Ru particles and thus promote N≡N bond cleavage, which is the rate determining step for ammonia synthesis.</p>

An intelligent quantitative risk assessment method for ammonia synthesis process

2021 ◽  
Vol 420 ◽  
pp. 129893
Author(s):  
Zijian Liu ◽  
Wende Tian ◽  
Zhe Cui ◽  
Honglong Wei ◽  
Chuankun Li
Keyword(s):  
Risk Assessment ◽  
Ammonia Synthesis ◽  
Assessment Method ◽  
Quantitative Risk Assessment ◽  
Synthesis Process ◽  
Risk Assessment Method

scholarly journals Tailoring Mesoporous Titania Features by Ultrasound-Assisted Sol-Gel Technique: Effect of Surfactant/Titania Precursor Weight Ratio

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1263
Author(s):  
Elvira Mahu ◽  
Cristina Giorgiana Coromelci ◽  
Doina Lutic ◽  
Iuliean Vasile Asaftei ◽  
Liviu Sacarescu ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Sol Gel ◽  
Weight Ratio ◽  
Soft Template ◽  
Synthesis Process ◽  
Mesoporous Titania ◽  
Cavitation Effect ◽  
Titania Precursor ◽  
Gel Technique ◽  
Ultrasound Assisted

A mesoporous titania structure has been prepared using the ultrasound-assisted sol-gel technique in order to find out a way to tailor its structure. The TiO2 obtained was compared to the same version of titania but synthesized by a conventional sol-gel method with the objective of understanding the effect of ultrasound in the synthesis process. All synthesis experiments were focused on the preparation of a titania photocatalyst. Thus, the anatase photocatalytic active phase of titania was proven by X-ray diffraction. Additionally, the ultrasonation treatment proved to increase the crystallinity of titania samples, being one of the requirements to having good photocatalytic activity for titania. The influence of surfactant/titania precursor weight ratio on the structural (XRD), textural (N2-sorption measurements), morphological (TEM), surface chemistry (FTIR) and optical properties (UVDR) was investigated. It was observed that the crystallite size, specific surface area, band gap energy and even photocatalytic activity was affected by the synergism occurring between cavitation effect and the surfactant/titania precursor weight ratio. The study yielded interesting great results that could be considered for further application of ultrasound to tailor mesoporous titania features via sol-gel soft template synthesis, against conventional sol-gel process.

Noble Metal Collection through Air: Perovskite Oxide as a Novel Collector

ChemPhysChem ◽  
2010 ◽  
Vol 12 (1) ◽  
pp. 109-111 ◽  
Author(s):  
Masakazu Daté ◽  
Katsuhiro Nomura ◽  
Hiroyuki Kageyama ◽  
Tadahiro Fujitani
Keyword(s):  
Noble Metal ◽  
Perovskite Oxide

Sol-Gel Synthesis and Characterization of Ultrafine ZrSiO4 Powder

2014 ◽  
Vol 906 ◽  
pp. 66-71
Author(s):  
Zhen Quan Li ◽  
Qiang Zhen ◽  
Ya Li Wang
Keyword(s):  
Wavelength Range ◽  
High Purity ◽  
Raw Materials ◽  
Formation Rate ◽  
Sol Gel ◽  
Molar Ratio ◽  
Sem And Tem ◽  
Homogeneous Product ◽  
Sol Gel Synthesis ◽  
Calcined Temperature

High purity ZrSiO4 powder were synthesized using Si (C2H5O)4 and ZrOCl2·8H2O as raw materials by the sol-gel method, LiCl was added as mineralizer to promote crystallization of zircon. The influences of molar ratio of Zr:Si, calcined time and calcined temperature on the synthesis of ZrSiO4 powder were investigated. XRD, SEM and TEM were used to characterize the powders. It was found that when the molar ratio of Zr:Si was 1:1.2, the calcined temperature was 1600°C and the calcined time was 4h, the high purity ZrSiO4 ultrafine powder was obtained. The ZrSiO4 formation began at 1300°C and when the gel was calcined at 1600°Cfor 4 h, the formation rate of ZrSiO4 was up to 95%. SEM and TEM studies reveal a homogeneous product with particle sizes on the order of 0.1-1μm. The IR emissivity of ultrafine ZrSiO4 is 0.892 at the whole wavelength range, and that is up to 0.951 at the wavelength range of 8-14 μm.

High-Speed Synthesis and Electric Properties of Magnesium Doped Lead Titanate Ceramics

2007 ◽  
Vol 121-123 ◽  
pp. 149-152
Author(s):  
Liang Sheng Qiang ◽  
Dong Yan Tang ◽  
Xing Hong Zhang ◽  
L. Jin
Keyword(s):  
Lead Titanate ◽  
High Speed ◽  
Sintering Temperature ◽  
Water Solution ◽  
Sol Gel ◽  
Electric Properties ◽  
Synthesis Process ◽  
Pure Lead ◽  
Alcohol Water ◽  
Titanate Ceramics

By adding methyl alcohol/water solution with certain concentration into sol to hydrolysis directly and sintering the fresh sol directly, lead titanate(PbTiO3) ceramics doped with magnesium are prepared by using magnesium acetate as doper to prohibit the disadvantages contained in conventional sol-gel method, such as low hydrolytic rate, high sintering temperature, long preparation period. The changes of structure, microstructure, synthesis process and electric properties of modified ceramics are studied in detail. The sizes and morphology of high purely and high density magnesium doped lead titanate nanocrystals thus obtained are observed by TEM photographs and the structures and affection of sintering temperature of to lattice constant and sizes of nanocrystals are detected by XRD. Electric properties detection results show that doped lead titanate ceramics exhibite excellent dielectric, ferroelectric and pyroelectric properties compare with pure lead titanate.

Sintering and Oxygen Ionic Conducting Properties of Bi2V0.9Co0.1O5.5-δ Derived from an EDTA-Citrate Precursor

2007 ◽  
Vol 124-126 ◽  
pp. 731-734
Author(s):  
Feng Zhang ◽  
Qing Xu ◽  
Duan Ping Huang ◽  
Wen Chen ◽  
Han Xing Liu ◽  
...  
Keyword(s):  
Sol Gel ◽  
Fine Powder ◽  
Synthesis Process ◽  
Complexing Agents ◽  
Aurivillius Phase ◽  
Disorder Phase Transition ◽  
Dense Microstructure ◽  
Ionic Conducting ◽  
Sintering Properties ◽  
The Difference

Bi2V0.9Co0.1O5.5-δ with a pure Aurivillius phase was synthesized by a sol-gel method using EDTA and citric as mixed complexing agents. It was found that homogeneous and fine powder (100-200 nm) with a pure Aurivillius phase can be produced by calcining the complex precursor at 450 °C for 1h in air. The sintering properties of Bi2V0.9Co0.1O5.5-δ were investigated in the range of 560-680 °C with respect to relativity density. Sintering at 640 °C was ascertained to be preferred for Bi2V0.9Co0.1O5.5-δ, producing a dense microstructure with uniform grains around 3-5 μm. The Bi2V0.9Co0.1O5.5-δ ceramic exhibits an oxygen ionic conductivity of 1.0×10-1 S·cm-1 at 600 °C. The difference between the activation energies for the ionic conducting in low and high temperature regions is qualitatively interpreted in terms of an order-disorder phase transition. This research demonstrates the advantage of the EDTA-citrate method in preparing Bi2V0.9Co0.1O5.5-δ with respect to the simplicity of synthesis process, desired morphology of synthesized powder, low sintering temperature and superior ionic conducting properties of ceramic specimen.

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