Plasma-driven catalysis process for toluene abatement: Effect of water vapor

Plasma-driven catalysis (PDC) was used to remove toluene in air. Water vapor is a critical operating parameter in this process. Its effect on toluene removal efficiency, carbon balance, CO 2 selectivity, and outlet O 3 concentration was systematically investigated. Results showed that water vapor imposed negative effect on toluene decomposition since it depressed the formation and catalytic decomposition of O 3. Water vapor deposited on the catalyst would cover the catalytic active sites, resulting in the deactivation of the catalyst. There was an optimum water vapor content for the highest carbon balance and CO 2 selectivity. The present paper sheds some insight into the effect of water vapor and provides a valuable basis for the application of the PDC technology. © 2010 IEEE.published_or_final_versio

Cobalt-based Nanoreactors in Combined Fischer-Tropsch Synthesis and Hydroprocessing: Effects on Methane and CO2_{2} Selectivity

Fischer-Tropsch synthesis: Four types of bi-functional catalysts with cobalt nanoparticles supported on meso- or microporous silicates or aluminosilicates are investigated regarding the obtained CO$_{2}$ and CH$_{4l}$ selectivity under low-temperature Fischer-Tropsch reaction conditions. In situ x-ray absorption spectroscopy results under industrially relevant conditions reveal that strong cobalt-support interactions and oxidized cobalt species are the main factors determining the selectivity depending on the specific support material used. The production of liquid hydrocarbons from syngas (CO and H$_{2}$) via the combined Fischer-Tropsch (FT) synthesis and hydroprocessing (HP) is a promising strategy to provide valuable chemicals and fuels based on renewable feedstocks. High yields of liquid products are essential for industrial implementation since short-chain side products like methane and CO$_{2}$ reduce the overall carbon efficiency, which holds true especially for bi-functional Co/zeolite catalysts. In order to investigate the influence of the support material properties on the methane and CO$_{2}$ selectivities in the combined FT and HP reaction, we synthesized four well-defined catalyst materials with similar cobalt particle sizes. The active material is supported on either meso- or microporous silicates or aluminosilicates. The catalytic properties are investigated in FT experiments at industrially relevant conditions (20 bar, 200–260 °C) and correlated with in situ x-ray absorption spectroscopy results to determine the chemical environment responsible for the selectivity observed. The origin of the high methane selectivity detected for crystalline and amorphous aluminosilicate was mainly traced back to the strong cobalt-support interactions. The high CO$_{2}$ selectivity, observed only for crystalline zeolite materials, is driven by the presence of oxidized cobalt species, while the acidic support in combination with micropores and possible overcracking leads to the observed drop in the C$_{5+}$ selectivity

Potential of Ceria-Zirconia-Based Materials in Carbon Soot Oxidation for Gasoline Particulate Filters

ZrO(2)and Ce(0.8)Zr(0.2)O(2)mixed oxides were prepared and tested in the oxidation of carbon soot at different oxygen partial pressures and degrees of catalyst/soot contact to investigate their activity under typical gasoline direct injection (GDI) operating conditions. Under reductive atmospheres, generation of oxygen vacancies occurs in Ce0.8Zr0.2O2, while no reduction is observed on ZrO2. Both materials can oxidize carbon under high oxygen partial pressures; however, at low oxygen partial pressures, the presence of carbon can contribute to the reduction of the catalyst and formation of oxygen vacancies, which can then be used for soot oxidation, increasing the overall performance. This mechanism is more efficient in Ce(0.8)Zr(0.2)O(2)than ZrO2, and depends heavily on the interaction and the degree of contact between soot and catalyst. Thus, the ability to form oxygen vacancies at lower temperatures is particularly helpful to oxidize soot at low oxygen partial pressures, and with higher CO(2)selectivity under conditions typically found in GDI engine exhaust gases

Hydrocarbon and soot oxidation over cerium and iron doped vanadium SCR catalysts

V$_{2}$O$_{5}$−WO$_{3}$/TiO$_{2}$ (VWTi) catalysts are widely employed for selective catalytic reduction (SCR) of NO$_{x}$. However, due to their poor thermal stability the application in diesel particulate filters (DPFs), i. e. 2‐way SCRonDPF is limited. In this study, the potential of Ce‐ and Fe‐doped VWTi systems for hydrocarbon and soot oxidation in addition to the SCR activity was systematically investigated for fresh and thermally aged samples. The formation of metal vanadates upon thermal aging, as identified by X‐ray diffraction, Raman and X‐ray adsorption spectroscopy, prevents drastic sintering of the support and maintains a high NO$_{x}$−SCR and hydrocarbon oxidation activity. Additionally, the doped VWTi catalysts show a slight increase of the CO$_{2}$ selectivity during hydrocarbon oxidation, which represents an important aspect for such multifunctional catalysts. Despite of the advantages, the formation of metal vanadates hinders the mobility of vanadium species and decreases the soot oxidation ability of the doped catalysts. Interestingly, a promising soot oxidation activity was identified for the VWTi−Fe sample after aging at 650 °C, which resulted in decomposition of the iron vanadate and generation of highly dispersed and mobile V$_{2}$O$_{5}$

Co3O4 catalysts on CeO2-ZrO2 supports and Co3O4-CeO2 catalysts on Al2O3/SiO2 supports for the oxidation of propylene

Different compositions of Co3O4 catalysts on CeO2-ZrO2 solid solution (Ce0.9Zr0.1O2 and Ce0.8Zr0.2O2) have been studied for the oxidation of propylene. The optional amount of Co3O4 active phase on CeO2-ZrO2 support of 30 wt% was found. The mixed Co3O4-CeO2-ZrO2 with the same composition of the optimal supported ones showed approximately the same activity, which was not higher than the activity of the mixed Co3O4-CeO2 catalyst. Catalytic activities of mixed Co3O4-CeO2 with different loading contents supported on high surface area supports (Al2O3, SiO2) were then measured. The optimal composition of active phase was still 30 wt% but the minimum temperature of the highest activity increased to above 300 degrees C due to the inert nature influence of the support

Team One Carbon Catcher Design Report

Overview The burning of fossil fuels largely contributes to the increase of CO2 in the atmosphere. The US Department of Transportation alone contributed almost 6 million metric tons of carbon dioxide emissions in 2018 (EIA). Due to this, this report proposes recycling captured CO2 into a base for cleaner burning fuel in order to reduce emissions from the transportation industry and many others, which has the potential to impact many areas. Extraction of atmospheric CO2 is possible through a membrane filtration system based on traditional nitrogen generation. The passive filtration system autonomously separates the CO2 from other air components, thereby reducing energy consumption. The system's working sensors and actuators utilize similar energy saving strategies, such as distributing cloud-computing services over multiple servers and mainframes to reduce computing power. The movement of air is directed by a scalable fan device, which is presented as a modular design to allow customization of fan parts to specific size and installation requirements. As an integrated device, Team 1’s Carbon Catcher operates with a high efficiency in order to maximize the commercial opportunity of converting captured CO2 into cleaner fuel while also reducing CO2 emissions and the greenhouse effect. Goal The goal of Team 1’s Carbon Catcher project proposal is to design a cost-effective, scalable, and modular atmospheric carbon dioxide removal system that is capable of being utilized in a range of urban environments and may fit a variety of different customer requirements or requests

Computational Screening of MOF-Based Mixed Matrix Membranes for CO 2

Atomically detailed simulations were used to examine CO2/N2 separation potential of metal organic framework- (MOF-) based mixed matrix membranes (MMMs) in this study. Gas permeability and selectivity of 700 new MMMs composed of 70 different MOFs and 10 different polymers were calculated for CO2/N2 separation. This is the largest number of MOF-based MMMs for which computational screening is done to date. Selecting the appropriate MOFs as filler particles in polymers resulted in MMMs that have higher CO2/N2 selectivities and higher CO2 permeabilities compared to pure polymer membranes. We showed that, for polymers that have low CO2 permeabilities but high CO2 selectivities, the identity of the MOF used as filler is not important. All MOFs enhanced the CO2 permeabilities of this type of polymers without changing their selectivities. Several MOF-based MMMs were identified to exceed the upper bound established for polymers. The methods we introduced in this study will create many opportunities to select the MOF/polymer combinations with useful properties for CO2 separation applications

Steam reforming of isobutanol for the production of synthesis gas over Ni/g-Al2O3 catalysts

Bio-isobutanol has received widespread attention as a bio-fuel and a source of chemicals and synthesis gas as part of an integrated biorefinery approach. The production of synthesis gas by steam reforming (SR) of isobutanol was investigated in a down-flow stainless steel fixed-bed reactor (FBR) over Ni/g-Al2O3 catalysts in the temperature range of 723–923 K. The NiO/g-Al2O3 catalysts were prepared by the wet impregnation method and reduced in the FBR prior to the reaction. The surface area, metal dispersion, crystalline phase, and reducibility of the prepared catalysts were determined using BET, chemisorption, XRD and TPR, respectively. From the TPR studies, the maximum hydrogen consumption was observed in the temperature range of 748–823 K for all the catalysts. The presence of nickel species was confirmed through the characterization of the catalysts using powder XRD. The time-on-stream (TOS) studies showed that the catalysts remained fairly stable for more than 10 h of TOS. The conversion of carbon to gaseous products (CCGP) was increased by increasing the nickel loading on g-Al2O3 and the temperature and by decreasing the weight hourly space velocity (WHSV). The hydrogen yield was increased by increasing the nickel loading on g-Al2O3, the WHSV, the steam-to-carbon mole ratio (SCMR), and the temperature. The selectivity to methane decreased at high reaction temperatures and SCMRs. The selectivity to CO decreased with increasing SCMRs and decreasing temperatures. The work was further extended to the thermodynamic equilibrium analysis of the SR of isobutanol under experimental conditions using Aspen Plus, and the equilibrium results were then compared to the experimental results. A reasonably good agreement was observed between the trends in the equilibrium and the experimental results

Propan-1-ol Oxidation Reaction on Au/TiO2 Catalysts

Alcohols such as propanol and n- butanol have been oxidised to aldehydes by resin- supported gold in the liquid phase, and several other primary and secondary alcohols have been oxidised with very high selectivity in vapour phase over a 1wt% Au/SiO2 catalyst between 373- 573K. In this work, the adsorption of propan-1-ol was carried over 1%Au/TiO2 catalysts prepared by deposition precipitation method. This was further investigated using Pulse Flow reactor, TPFRP, TPD, and XRD,. The adsorption of propan-1-ol over TiO2 (P25) indicated a full monolayer with much of it in a dissociated state, forming propoxy group on the cationic site and hydroxyl group at anions. The propoxy is relatively stable until about 250oC, at which dehydration to propene occurs by bimolecular surface reaction. As the concentration of propoxy on the surface disappear, so mechanism reverts to a decomposition pathway, producing CO2 and H2O. However, the presence of gold on the catalyst is marked with complete conversion of propan-1-ol at low temperature (230oC) lower than Titania (300oC). Similarly, propan-1-ol oxidation on Au/TiO2 catalyst was followed by dehydration to propene at 300oC (Characteristic of TiO2) and dehydrogenation to propanal at high temperature. The evolution of CO2 and H2 appear to be due to the production of formate species on the surface of the catalyst. This formate species is mainly involved in the complete oxidation reaction of propan-1-ol on the catalysts.Keywords: Gold Catalysis, Propan-1-ol Oxidation, TPD, TPFRP, XR