scholarly journals Catalytic Performance of Nitrogen-Doped Activated Carbon Supported Pd Catalyst for Hydrodechlorination of 2,4-Dichlorophenol or Chloropentafluoroethane

Molecules ◽  
2019 ◽  
Vol 24 (4) ◽  
pp. 674 ◽  
Author(s):  
Haodong Tang ◽  
Bin Xu ◽  
Meng Xiang ◽  
Xinxin Chen ◽  
Yao Wang ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Liquid Phase ◽  
Gas Phase ◽  
Nitrogen Doping ◽  
Catalyst Surface ◽  
Catalytic Performance ◽  
Atomic Ratio ◽  
Pd Catalyst ◽  
Nitrogen Doped ◽  
The Stability

Nitrogen-doped activated carbon (N-AC) obtained through the thermal treatment of a mixture of HNO3-pretreated activated carbon (AC) and urea under N2 atmosphere at 600 °C was used as the carrier of Pd catalyst for both liquid-phase hydrodechlorination of 2,4-dichlorophenol (2,4-DCP) and gas-phase hydrodechlorination of chloropentafluoroethane (R-115). The effects of nitrogen doping on the dispersion and stability of Pd, atomic ratio of Pd/Pd2+ on the surface of the catalyzer, the catalyst’s hydrodechlorination activity, as well as the stability of N species in two different reaction systems were investigated. Our results suggest that, despite no improvement in the dispersion of Pd, nitrogen doping may significantly raise the atomic ratio of Pd/Pd2+ on the catalyst surface, with a value of 1.2 on Pd/AC but 2.2 on Pd/N-AC. Three types of N species, namely graphitic, pyridinic, and pyrrolic nitrogen, were observed on the surface of Pd/N-AC, and graphitic nitrogen was stable in both liquid-phase hydrodechlorination of 2,4-DCP and gas-phase hydrodechlorination of R-115, with pyridinic and pyrrolic nitrogen being unstable during gas-phase hydrodechlorination of R-115. As a result, the average size of Pd nanocrystals on Pd/N-AC was almost kept unchanged after liquid-phase hydrodechlorination of 2,4-DCP, whereas crystal growth of Pd was clearly observed on Pd/N-AC after gas-phase hydrodechlorination of R-115. The activity test revealed that Pd/N-AC exhibited a much better performance than Pd/AC in liquid-phase hydrodechlorination of 2,4-DCP, probably due to the enhanced stability of Pd exposed to the environment resulting from nitrogen doping as suggested by the higher atomic ratio of Pd/Pd2+ on the catalyst surface. In the gas-phase hydrodechlorination of R-115, however, a more rapid deactivation phenomenon occurred on Pd/N-AC than on Pd/AC despite a higher activity initially observed on Pd/N-AC, hinting that the stability of pyridinic and pyrrolic nitrogen plays an important role in the determination of catalytic performance of Pd/N-AC.

scholarly journals Preformed Pd-Based Nanoparticles for the Liquid Phase Decomposition of Formic Acid: Effect of Stabiliser, Support and Au–Pd Ratio

2020 ◽  
Vol 10 (5) ◽  
pp. 1752 ◽  
Author(s):  
Felipe Sanchez ◽  
Ludovica Bocelli ◽  
Davide Motta ◽  
Alberto Villa ◽  
Stefania Albonetti ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Formic Acid ◽  
Pd Nanoparticles ◽  
Catalytic Performance ◽  
Atomic Ratio ◽  
Phase Decomposition ◽  
Acid Effect ◽  
Formic Acid Decomposition ◽  
Structure Morphology

Hydrogen is one of the most promising energy carriers for the production of electricity based on fuel cell hydrogen technology. Recently, hydrogen storage chemicals, such as formic acid, have been proposed to be part of the long-term solution towards hydrogen economy for the future of our planet. Herein we report the synthesis of preformed Pd nanoparticles using colloidal methodology varying a range of specific experimental parameters, such as the amount of the stabiliser and reducing agent, nature of support and Pd loading of the support. The aforementioned parameters have shown to affect mean Pd particle size, Pd oxidation, atomic content of Pd on the surface as well as on the catalytic performance towards formic acid decomposition. Reusability studies were carried out using the most active monometallic Pd material with a small loss of activity after five uses. The catalytic performance based on the Au–Pd atomic ratio was evaluated and the optimum catalytic performance was found to be with the Au/Pd atomic ratio of 1/3, indicating that the presence of a small amount of Pd is essential to promote significantly Au activity for the liquid phase decomposition of formic acid. Thorough characterisation has been carried out by means of XPS, SEM-EDX, TEM and BET. The observed catalytic performance is discussed in terms of the structure/morphology and composition of the supported Pd and Au–Pd nanoparticles.

scholarly journals Nitrogen-Doped Carbonaceous Materials for Removal of Phenol from Aqueous Solutions

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Magdalena Hofman ◽  
Robert Pietrzak
Keyword(s):  
Aqueous Solution ◽  
Activated Carbon ◽  
Liquid Phase ◽  
Carbonaceous Material ◽  
Phase Changes ◽  
Waste Materials ◽  
Isotherm Models ◽  
Phenol Content ◽  
Nitrogen Doped ◽  
Adsorption Isotherm Models

Carbonaceous material (brown coal) modified by pyrolysis, activation, and enrichment in nitrogen, with two different factor reagents, have been used as adsorbent of phenol from liquid phase. Changes in the phenol content in the test solutions were monitored after subsequent intervals of adsorption with selected adsorbents prepared from organic materials. Significant effect of nitrogen present in the adsorbent material on its adsorption capacity was noted. Sorption capacity of these selected materials was found to depend on the time of use, their surface area, and pore distribution. A conformation to the most well-known adsorption isotherm models, Langmuir, and Freundlich ones, confirms the formation of mono- and heterolayer solute (phenol) coverage on the surface of the adsorbent applied herein. The materials proposed as adsorbents of the aqueous solution contaminants were proved effective, which means that the waste materials considered are promising activated carbon precursors for liquid phase adsorbents for the environmental protection.

scholarly journals Zinc-Chromium oxide catalyst for gas-phase ketonisation of pentanoic acid

2016 ◽  
Vol 6 (2) ◽  
pp. 1-6 ◽  
Author(s):  
Mohammed Al-ghamdi ◽  
Hossein Bayahia
Keyword(s):  
Gas Phase ◽  
Mixed Oxides ◽  
Ambient Pressure ◽  
Catalytic Performance ◽  
Atomic Ratio ◽  
Bet Surface Area ◽  
Catalyst Characterization ◽  
Pentanoic Acid ◽  
Mixed Catalyst ◽  
Stable Performance

Oxides of Zinc and Chromium mixed catalyst with different atomic ratios of Zinc and Chromium were tested in the ketonisation of pentanoic acid in the gas phase. These catalysts were active to form 5-nonanone, at 300 – 400 oC and ambient pressure. It was found that Zn-Cr with an atomic ratio (10:1) gave the best catalytic performance in comparison with other oxides with higher or lower atomic ratio of Zn and Cr mixed oxides, ZnO and Cr2O3. In this test, Zn-Cr (10:1) gave 82% of selectivity for 5-nonanone as the main product at 86% of conversion of the acid at 350oC. The catalyst showed stable performance at the best selected conditions with a small decrease in acid conversion. For catalyst characterization, BET surface area and porosity technique, X-ray diffraction and DRIFTS of pyridine adsorption were used.

Carbonization conditions influence the emission characteristics and the stability against photobleaching of nitrogen doped carbon dots

Nanoscale ◽  
2017 ◽  
Vol 9 (32) ◽  
pp. 11730-11738 ◽  
Author(s):  
Yuan Xiong ◽  
Julian Schneider ◽  
Claas J. Reckmeier ◽  
He Huang ◽  
Peter Kasák ◽  
...  
Keyword(s):  
Carbon Dots ◽  
Nitrogen Doping ◽  
Luminescence Properties ◽  
Emission Characteristics ◽  
Nitrogen Doped ◽  
The Stability ◽  
Doped Carbon Dots ◽  
Nitrogen Doped Carbon

Our study provides insights into the origin of the luminescence properties of carbon dots, by addressing the role of carbonization conditions, nitrogen doping, and formation of molecular fluorophores.

scholarly journals Zinc-Chromium oxide catalyst for gas-phase ketonisation of pentanoic acid

2016 ◽  
Vol 6 (2) ◽  
pp. 1
Author(s):  
Mohammed Al-ghamdi ◽  
Hossein Bayahia
Keyword(s):  
Gas Phase ◽  
Mixed Oxides ◽  
Ambient Pressure ◽  
Catalytic Performance ◽  
Atomic Ratio ◽  
Bet Surface Area ◽  
Catalyst Characterization ◽  
Pentanoic Acid ◽  
Mixed Catalyst ◽  
Stable Performance

Oxides of Zinc and Chromium mixed catalyst with different atomic ratios of Zinc and Chromium were tested in the ketonisation of pentanoic acid in the gas phase. These catalysts were active to form 5-nonanone, at 300 – 400 <sup>o</sup>C and ambient pressure.  It found that Zn-Cr with an atomic ratio (10:1) gave the best catalytic performance in  comparison with other oxides with higher or lower atomic ratio of Zn and Cr mixed oxides, ZnO and Cr<sub>2</sub>O<sub>3</sub>. In this test, Zn-Cr (10:1) gave 82% selectivity of 5-nonanone as the main product at 86% conversion of acid at 350<sup>o</sup>C. The catalyst showed stable performance at the best selected conditions with a small decrease of acid conversion. For catalyst characterization, BET surface area and porosity technique, X-ray diffraction and DRIFTS of pyridine adsorption were used.

scholarly journals Improvement of low-temperature NH3-SCR catalytic performance over nitrogen-doped MOx–Cr2O3–La2O3/TiO2–N (M = Cu, Fe, Ce) catalysts

RSC Advances ◽  
2021 ◽  
Vol 11 (37) ◽  
pp. 22780-22788
Author(s):  
Xiaoyi Sun ◽  
Qingjie Liu ◽  
Shuai Liu ◽  
Xintang Zhang ◽  
Shanshan Liu
Keyword(s):  
Low Temperature ◽  
Nitrogen Doping ◽  
Catalytic Performance ◽  
Impregnation Method ◽  
Nitrogen Doped ◽  
Nh3 Scr

A series of MOx–Cr2O3–La2O3/TiO2–N (M = Cu, Fe, Ce) catalysts with nitrogen doping were prepared via the impregnation method.

scholarly journals Effect of textual features and surface properties of activated carbon on the production of hydrogen peroxide from hydroxylamine oxidation

RSC Advances ◽  
2017 ◽  
Vol 7 (41) ◽  
pp. 25305-25313 ◽  
Author(s):  
Wei Song ◽  
Lin Yu ◽  
Xiaowei Xie ◽  
Zhifeng Hao ◽  
Ming Sun ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Activated Carbon ◽  
Liquid Phase ◽  
Gas Phase ◽  
Surface Properties ◽  
Textural Features ◽  
Production Of Hydrogen ◽  
Textual Features

Herein, the textural features and surface properties of activated carbon were mediated by oxidation in the gas-phase or liquid-phase.

Role of lattice oxygen in oxidative steam reforming of toluene as a tar model compound over Ni/La0.8Sr0.2AlO3 catalyst

2015 ◽  
Vol 5 (7) ◽  
pp. 3585-3597 ◽  
Author(s):  
Usman Oemar ◽  
Ming Li Ang ◽  
Yin Chee Chin ◽  
Kus Hidajat ◽  
Sibudjing Kawi
Keyword(s):  
Gas Phase ◽  
Model Compound ◽  
Catalyst Surface ◽  
Catalytic Performance ◽  
Lattice Oxygen ◽  
Tar Model Compound ◽  
Steam Reforming Of Toluene ◽  
Direct Partial Oxidation ◽  
Partial Oxidation Of Toluene

High catalytic performance of Ni/La0.8Sr0.2AlO3 catalyst due to high amount of mobile lattice oxygen which favors direct partial oxidation of toluene while gas-phase oxygen favors complete oxidation. Both oxygen species actively oxidize coke deposited on catalyst surface, conferring coking resistance.

Sign in / Sign up

Export Citation Format

Share Document