Electrocatalytic dechlorination of atrazine

2002 ◽  
Vol 80 (2) ◽  
pp. 200-206 ◽  
Author(s):  
Naomi L Stock ◽  
Nigel J Bunce
Keyword(s):  
Palladium Catalysts ◽  
Catalyst Concentration ◽  
Lag Time ◽  
Vitreous Carbon ◽  
Reticulated Vitreous Carbon ◽  
Hydrogen Atoms ◽  
Pd Catalysts ◽  
Noble Metal Catalysts ◽  
Catalytically Active ◽  
Electrocatalytic Dechlorination

Atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine), a photosynthetic inhibitor that is used in large quantities for weed control in corn and sorghum, is dechlorinated in aqueous solution upon electrolysis at a reticulated vitreous carbon cathode in the presence of noble-metal catalysts. Electrocatalytic hydrogenolysis to 2-ethylamino-4-isopropylamino-s-triazine occurs in quantitative yield, and is most efficient with palladium-based catalysts. Current efficiency increases with atrazine and catalyst concentration, and decreasing current density. A previously unobserved phenomenon with Pd catalysts is that current must be passed for a certain time before dechlorination commences. This lag time is explained in terms of the palladium lattice absorbing a finite amount of hydrogen before catalytically active hydrogen atoms appear on the catalyst surface.Key words: electrocatalytic hydrogenoloysis, dechlorination, atrazine, palladium catalysts.

Model reactions for the study of hydrogenation and acidic activity of palladium catalysts

1987 ◽  
Vol 52 (8) ◽  
pp. 2019-2027 ◽  
Author(s):  
Libor Červený ◽  
Nguyen Thi Du ◽  
Ivo Paseka
Keyword(s):  
Palladium Catalysts ◽  
Styrene Oxide ◽  
Side Reactions ◽  
Pd Catalysts ◽  
Variable Parameters ◽  
Acid Properties ◽  
Liquid Phase Hydrogenation ◽  
Acid Catalysed Reactions ◽  
Different Content ◽  
Model Reactions

Palladium catalysts have been used to study the hydrogenation of 1-phenyl-2-butene-1-ol which is accompanied by several side reactions considered to be acid-catalysed. Another model reaction studied was dehydration and subsequent hydrogenation or hydrogenolysis of 1-phenyl-1,3-propanediol to 3-phenyl-1-propanol, accompanied by formation of propylbenzene. The dehydration and propylbenzene formation can be again classified as acid-catalysed reactions. Another one is methanolysis of styrene oxide taking place under conditions of liquid phase hydrogenation due to the acid properties of Pd-H systems. Hydrogenation activity of Pd catalysts was tested by hydrogenation of cyclohexene. Sixteen Pd catalysts on different supports and with different content of active component were used, their activity and selectivity was determined and the effect of variable parameters in the synthesis of these catalysts on the activity and selectivity is discussed.

scholarly journals Recent advances on modified reticulated vitreous carbon for water and wastewater treatment – A mini-review

Chemosphere ◽  
2021 ◽  
pp. 131573
Author(s):  
Vanessa M. Vasconcelos ◽  
Géssica O.S. Santos ◽  
Katlin I.B. Eguiluz ◽  
Giancarlo R. Salazar-Banda ◽  
Iara de Fatima Gimenez
Keyword(s):  
Wastewater Treatment ◽  
Vitreous Carbon ◽  
Reticulated Vitreous Carbon ◽  
Water And Wastewater Treatment ◽  
Recent Advances ◽  
Water And Wastewater

scholarly journals Development of palladium catalysts modified by ruthenium and molybdenum as anode in direct ethanol fuel cell

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Yonis Fornazier Filho ◽  
Ana Caroliny Carvalho da Cruz ◽  
Rolando Pedicini ◽  
José Ricardo Cezar Salgado ◽  
Priscilla Paiva Luz ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Palladium Catalysts ◽  
Carbon Support ◽  
X Ray Diffraction ◽  
Direct Ethanol Fuel Cell ◽  
Pd Catalysts ◽  
Bifunctional Mechanism ◽  
Catalytic Activities ◽  
Intrinsic Mechanism ◽  
Ternary Catalysts

AbstractPhysical and electrochemical properties of Pd catalysts combined with Ru and Mo on carbon support were investigated. To this end, Pd, Pd1.3Ru1.0, Pd3.2Ru1.3Mo1.0 and Pd1.5Ru0.8Mo1.0 were synthesized on Carbon Vulcan XC72 support by the method of thermal decomposition of polymeric precursors and then physically and electrochemically characterized. The highest reaction yields are obtained for Pd3.2Ru1.3Mo1.0/C and Pd1.5Ru0.8Mo1.0/C and, as demonstrated by thermal analysis, they also show the smallest metal/carbon ratio compared the other catalysts. XRD (X-ray Diffraction) and Raman analyses show the presence of PdO and RuO2 for the Pd/C and the Pd1.3Ru1.0/C catalysts, respectively, a fact not observed for the Pd3.2Ru1.3 Mo1.0 /C and the Pd1.5Ru0.8Mo1.0/C catalysts. The catalytic activities were tested for the ethanol oxidation in alkaline medium. Cyclic voltammetry (CV) shows Pd1.3Ru1.0/C exhibiting the highest peak of current density, followed by Pd3.2Ru1.3Mo1.0/C, Pd1.5Ru0.8Mo1.0/C and Pd/C. From, chronoamperometry (CA), it is possible to observe the lowest rate of poisoning for the Pd1.3Ru1.0/C, followed by Pd3.2Ru1.3Mo1.0/C, Pd1.5Ru0.8Mo1.0/C and Pd/C. These results suggested that catalytic activity of the binary and the ternary catalysts are improved in comparison with Pd/C. The presence of RuO2 activated the bifunctional mechanism and improved the catalytic activity in the Pd1.3Ru1.0/C catalyst. The addition of Mo in the catalysts enhanced the catalytic activity by the intrinsic mechanism, suggesting a synergistic effect between metals. In summary, we suggest that it is possible to synthesize ternary PdRuMo catalysts supported on Carbon Vulcan XC72, resulting in materials with lower poisoning rates and lower costs than Pd/C. Graphic abstract

Reticulated vitreous carbon as a scaffold for enzymatic fuel cell designing

2017 ◽  
Vol 95 ◽  
pp. 1-7 ◽  
Author(s):  
Michal Kizling ◽  
Maciej Dzwonek ◽  
Bartłomiej Olszewski ◽  
Paweł Bącal ◽  
Łukasz Tymecki ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Vitreous Carbon ◽  
Reticulated Vitreous Carbon ◽  
Enzymatic Fuel Cell

Hybrid lead-acid battery with reticulated vitreous carbon as a carrier- and current-collector of negative plate

2010 ◽  
Vol 195 (22) ◽  
pp. 7530-7534 ◽  
Author(s):  
A. Czerwiński ◽  
S. Obrębowski ◽  
J. Kotowski ◽  
Z. Rogulski ◽  
J. Skowroński ◽  
...  
Keyword(s):  
Current Collector ◽  
Vitreous Carbon ◽  
Lead Acid Battery ◽  
Reticulated Vitreous Carbon ◽  
Negative Plate ◽  
Lead Acid
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