Activated carbon from waste biomass as catalyst support: formation of active phase in copper and cobalt catalysts for methanol decomposition

2015 ◽  
Vol 22 (5) ◽  
pp. 1127-1136 ◽  
Author(s):  
Tanya Tsoncheva ◽  
Izabela Genova ◽  
Ivanka Stoycheva ◽  
Ivanka Spassova ◽  
Radostina Ivanova ◽  
...  
2021 ◽  
Author(s):  
Radostina Ivanova ◽  
Momtchil Dimotrov ◽  
Daniela Kovacheva ◽  
Boyko Tsyntsarski ◽  
Ivanka Spassova ◽  
...  

2021 ◽  
Author(s):  
Petar Djinović ◽  
Janez Zavašnik ◽  
Janvit Teržan ◽  
Ivan Jerman

AbstractCeO2, V2O5 and CeVO4 were synthesised as bulk oxides, or deposited over activated carbon, characterized by XRD, HRTEM, CO2-TPO, C3H8-TPR, DRIFTS and Raman techniques and tested in propane oxidative dehydrogenation using CO2. Complete oxidation of propane to CO and CO2 is favoured by lattice oxygen of CeO2. The temperature programmed experiments show the ~ 4 nm AC supported CeO2 crystallites become more susceptible to reduction by propane, but less prone to re-oxidation with CO2 compared to bulk CeO2. Catalytic activity of CeVO4/AC catalysts requires a 1–2 nm amorphous CeVO4 layer. During reaction, the amorphous CeVO4 layer crystallises and several atomic layers of carbon cover the CeVO4 surface, resulting in deactivation. During reaction, V2O5 is irreversibly reduced to V2O3. The lattice oxygen in bulk V2O5 favours catalytic activity and propene selectivity. Bulk V2O3 promotes only propane cracking with no propene selectivity. In VOx/AC materials, vanadium carbide is the catalytically active phase. Propane dehydrogenation over VC proceeds via chemisorbed oxygen species originating from the dissociated CO2. Graphic Abstract


Fuel ◽  
1986 ◽  
Vol 65 (10) ◽  
pp. 1436-1446 ◽  
Author(s):  
H. Jüntgen

2019 ◽  
Author(s):  
Kevin Gu ◽  
Eric J. Kim ◽  
Sunil K. Sharma ◽  

<p>Carbon aerogel possesses unique structural and electrical properties, such as high mesopore volume, specific surface area, and electrical conductivity, which make it suitable for use as a catalyst support in Proton Exchange Membrane Fuel Cells (PEMFC). In this study, we present a novel synthesis of highly mesoporous carbon aerogel via ambient-drying and investigate its application in PEMFCs. The structural effects of activation on carbon aerogel were also studied. The TEM, XRF, Non Localized Density Function Theory (NLDFT) and BJH analysis were carried out to observe the morphology and pore structure. Pt on carbon aerogel and activated carbon aerogel show efficient activity in both oxygen reduction and hydrogen oxidation reactions compared to Pt on Vulcan XC-72, with increases up to 715% and 195% in specific power density, respectively. The enhanced performance of carbon aerogel is attributed to its large specific surface area and high mesopore to micropore ratio. Accelerated stress tests show that carbon aerogel has comparable durability with Vulcan XC-72, while activated carbon aerogel is less durable than both materials. Thus, the mesoporous carbon aerogel provides an efficient, lower-cost alternative to existing microporous carbon material as a catalyst support in PEMFCs.</p><p></p>


Catalysts ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 857 ◽  
Author(s):  
Harrison Williams ◽  
Muthu K. Gnanamani ◽  
Gary Jacobs ◽  
Wilson D. Shafer ◽  
David Coulliette

Nearly a century ago, Fischer and Tropsch discovered a means of synthesizing organic compounds ranging from C1 to C70 by reacting carbon monoxide and hydrogen on a catalyst. Fischer–Tropsch synthesis (FTS) is now known as a pseudo-polymerization process taking a mixture of CO as H2 (also known as syngas) to produce a vast array of hydrocarbons, along with various small amounts of oxygenated materials. Despite the decades spent studying this process, it is still considered a black-box reaction with a mechanism that is still under debate. This investigation sought to improve our understanding by taking data from a series of experimental Fischer–Tropsch synthesis runs to build a computational model. The experimental runs were completed in an isothermal continuous stirred-tank reactor, allowing for comparison across a series of completed catalyst tests. Similar catalytic recipes were chosen so that conditional comparisons of pressure, temperature, SV, and CO/H2 could be made. Further, results from the output of the reactor that included the deviations in product selectivity, especially that of methane and CO2, were considered. Cobalt was chosen for these exams for its industrial relevance and respectfully clean process as it does not intrinsically undergo the water–gas shift (WGS). The primary focus of this manuscript was to compare runs using cobalt-based catalysts that varied in two oxide catalyst supports. The results were obtained by creating two differential equations, one for H2 and one for CO, in terms of products or groups of products. These were analyzed using sensitivity analysis (SA) to determine the products or groups that impact the model the most. The results revealed a significant difference in sensitivity between the two catalyst–support combinations. When the model equations for H2 and CO were split, the results indicated that the CO equation was significantly more sensitive to CO2 production than the H2 equation.


Molecules ◽  
2020 ◽  
Vol 25 (18) ◽  
pp. 4063
Author(s):  
Arnon Khamkeaw ◽  
Tatdanai Asavamongkolkul ◽  
Tianpichet Perngyai ◽  
Bunjerd Jongsomjit ◽  
Muenduen Phisalaphong

The porous carbon (bacterial cellulose (BC)-activated carbon (AC)(BA)) prepared via two-step activation of bacterial nanocellulose by treatments with potassium hydroxide (KOH) and then phosphoric acid (H3PO4) solutions showed superior adsorption properties and effective performance as catalyst support. BC-AC(BA) had an open and interconnected multi-porous structure, consisting of micropores (0.23 cm3/g), mesopores (0.26 cm3/g), and macropores (4.40 cm3/g). The BET surface area and porosity were 833 m2/g and 91.2%, respectively. The methylene blue adsorption test demonstrated that BC-AC(BA) was superior in its mass transfer rate and adsorption capacities. Moreover, BC-AC(BA) modified by H3PO4 treatment showed a significant enhancement of catalytic performance for dehydration of ethanol. At the reaction temperature of 250–400 °C, 30P/BC-AC(BA) gave ethanol conversion at 88.4–100%, with ethylene selectivity of 82.6–100%, whereas, high selectivity for diethyl ether (DEE) at 75.2%, at ethanol conversion of 60.1%, was obtained at the reaction temperature of 200 °C.


2013 ◽  
Vol 47 (4) ◽  
pp. 347-364 ◽  
Author(s):  
MS Islam ◽  
MA Rouf

A review of the production of activated carbons from waste biomass has been presented. The effects of various process parameters on the pyrolysis stage have been reviewed. Influences of activating conditions, physical and chemical, on the active carbon properties have been discussed. Under certain process conditions several active carbons with BET surface areas, ranging between 250 and 2410 m2/g and pore volumes of 0.022 and 91.4 cm3/g, have been produced. A comparison in characteristics and uses of activated carbons from waste biomass with those of commercial carbons has been made. Waste biomass being highly efficient, low cost and renewable sources of activated carbon production. Bangladesh J. Sci. Ind. Res. 47(4), 347-364, 2012 DOI: http://dx.doi.org/10.3329/bjsir.v47i4.14064


2013 ◽  
Vol 38 (25) ◽  
pp. 10364-10372 ◽  
Author(s):  
Palanichamy Kalyani ◽  
Ariharaputhiran Anitha ◽  
Andre Darchen

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