Deactivation Mechanism Study for Sulfur-Tolerance Enhanced NiO Nanocatalysts of Lean Methane Oxidation

2021 ◽  
Vol 125 (4) ◽  
pp. 2485-2491
Author(s):  
Jianzhou Wu ◽  
Kaimin Du ◽  
Jianwei Che ◽  
Shihui Zou ◽  
Liping Xiao ◽  
...  
Keyword(s):  
Methane Oxidation ◽  
Sulfur Tolerance ◽  
Mechanism Study ◽  
Deactivation Mechanism

Hydrotreating of waste cooking oil over supported CoMoS catalyst – Catalyst deactivation mechanism study

2017 ◽  
Vol 443 ◽  
pp. 228-240 ◽  
Author(s):  
Hui Wang ◽  
Guoliang Li ◽  
Kyle Rogers ◽  
Hongfei Lin ◽  
Ying Zheng ◽  
...  
Keyword(s):  
Catalyst Deactivation ◽  
Waste Cooking Oil ◽  
Mechanism Study ◽  
Cooking Oil ◽  
Deactivation Mechanism

scholarly journals A deactivation mechanism study of phosphorus-poisoned diesel oxidation catalysts: model and supplier catalysts

2020 ◽  
Vol 10 (16) ◽  
pp. 5602-5617
Author(s):  
Aiyong Wang ◽  
Jihao Wang ◽  
Sahil Sheti ◽  
Sandra Dahlin ◽  
Joonsoo Han ◽  
...  
Keyword(s):  
Oxidation Catalysts ◽  
Mechanism Study ◽  
Catalytic Behavior ◽  
Phosphorus Poisoning ◽  
Diesel Oxidation Catalysts ◽  
Diesel Oxidation ◽  
Monolith Catalysts ◽  
Deactivation Mechanism

The effect of phosphorus poisoning on the catalytic behavior of diesel oxidation catalysts was investigated over model and supplier monolith catalysts, i.e., Pd–Pt/Al2O3.

Methane Oxidation on a Coverage Layer Study

2008 ◽  
Author(s):  
Juliana L. Rose ◽  
Pedro Paulo F. Gouvêa ◽  
Cláudio F. Mahler
Keyword(s):  
Methane Oxidation

Ultra-Low Amounts of Palladium (0.005-0.05 Wt% Pd) Supported on Titania: Remarkable Low-Temperature Activity for NO Reduction with CO and Structure-Function Property Relationships in Methane Oxidation

2020 ◽  
Author(s):  
Konstantin Khivantsev ◽  
Libor Kovarik ◽  
Nicholas R. Jaegers ◽  
János Szanyi ◽  
Yong Wang
Keyword(s):  
Nitric Oxide ◽  
Carbon Monoxide ◽  
Methane Oxidation ◽  
Steam Reforming ◽  
Methane Steam Reforming ◽  
Oxide Reduction ◽  
Water Steam ◽  
Methane Steam ◽  
Anatase Titania ◽  
Nitric Oxide Reduction

<p>Atomically dispersed Pd +2 cations with ultra-dilute loading of palladium (0.005-0.05 wt%) were anchored on anatase titania and characterized with FTIR, microscopy and catalytic tests. CO infrared adsorption produces a sharp, narrow mono-carbonyl Pd(II)-CO band at ~2,130 cm<sup>-1</sup> indicating formation of highly uniform and stable Pd+2 ions on anatase titania. The 0.05 wt% Pd/TiO<sub>2</sub> sample was evaluated for methane combustion under dry and wet (industrially relevant) conditions in the presence and absence of carbon monoxide. Notably, we find the isolated palladium atoms respond dynamically upon oxygen concentration modulation (switching-on and switching off). When oxygen is removed from the wet methane stream, palladium ions are reduced to metallic state by methane and catalyze methane steam reforming instead of complete methane oxidation. Re-admission of oxygen restores Pd<sup>+2</sup> cations and switches off methane steam reforming activity. Moreover, 0.05 wt% Pd/TiO<sub>2</sub> is a competent CO oxidation catalyst in the presence of water steam with 90% CO conversion and TOF ~ 4,000 hr<sup>-1</sup> at 260 ⁰C. </p><p>More importantly, we find that diluting 0.05 wt% Pd/titania sample with titania to ultra-low 0.005 wt% palladium loading produces a remarkably active material for nitric oxide reduction with carbon monoxide under industrially relevant conditions with >90% conversion of nitric oxide at 180 ⁰C (~460 ppm NO and 150 L/g*hr flow rate in the presence of >2% water steam) and TOF ~6,000 hr<sup>-1</sup>. Pd thus outperforms state-of-the-art rhodium containing catalysts with (15-20 times higher rhodium loading; rhodium is ~ 3 times more expensive than palladium). Furthermore, palladium catalysts are more selective towards nitrogen and produce significantly less ammonia relative to the more traditional rhodium catalysts due to lower Pd amount nd lower water-gas-shift activity. Our study is the first example of utilizing ultra-low (0.05 wt% and less) noble metal (Pd) amounts to produce heterogeneous catalysts with extraordinary activity for nitric oxide reduction. This opens up a pathway to study other Pd, Pt and Rh containing materials with ultra-low loadings of expensive noble metals dispersed on titania or titania-coated oxides for industrially relevant nitric oxide abatement.</p>

Assemblies of D-peptides for Targeting Cell Nucleolus

2019 ◽  
Author(s):  
Huaimin Wang ◽  
Zhaoqianqi Feng ◽  
Weiyi Tan ◽  
Bing Xu
Keyword(s):  
Particle Morphology ◽  
Side Chain ◽  
Mechanism Study ◽  
Structural Analogue ◽  
Hydrophobic Residues ◽  
Subcellular Organelles ◽  
First Case ◽  
New Strategy ◽  
Peptide Derivative ◽  
Peptide Nanoparticles

<p>Selectively targeting cell nucleolus remains a challenge. Here we report the first case that D-peptides form membraneless molecular condensates with RNA for targeting cell nucleolus. A D-peptide derivative, enriched with lysine and hydrophobic residues, self-assembles to form nanoparticles, which enter cells through clathrin dependent endocytosis and mainly accumulate at cell nucleolus. Structural analogue of the D-peptide reveals that particle morphology of the assemblies, which depends on the side chain modification, favors the cellular uptake. Contrasting to those of the D-peptide, the assemblies of the corresponding L-enantiomer largely localize in cell lysosomes. Preliminary mechanism study suggests that the D-peptide nanoparticles interact with RNA to form membraneless condensates in the nucleolus, which further induces DNA damage and results in cell death. This work illustrates a new strategy for rationally designing supramolecular assemblies of D-peptides for targeting subcellular organelles.</p>

Environmental Factors and Deactivation Mechanism of Au/α-Fe2O3 Catalyst during Storage in Ambient Air

2011 ◽  
Vol 31 (12) ◽  
pp. 1489-1495 ◽  
Author(s):  
Jiying WEI ◽  
Guifang FAN ◽  
Feng JIANG ◽  
Zhenzhong ZHANG ◽  
Lan ZHANG
Keyword(s):  
Environmental Factors ◽  
Ambient Air ◽  
Deactivation Mechanism
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