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Articles 1 - 27 of 27
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Fast Pyrolysis Of Coconut Biomass--An Ftir Study, Tritti Siengchum, Matthew Isenberg, Steven Chuang
Fast Pyrolysis Of Coconut Biomass--An Ftir Study, Tritti Siengchum, Matthew Isenberg, Steven Chuang
Steven S.C. Chuang
The reaction pathway of coconut shell fast pyrolysis was studied by analysis of the transient evolution product profiles as a function of temperature, measured directly in the sample bed. Fast pyrolysis of coconut shell produced (i) pyrolysis liquid containing CH, CO, and COC bands, (ii) char with the absence of COH and CO suggesting that ether and carbonyl compounds were decomposed below 600 °C, and (iii) gaseous product majorly consisting of CO2. Increase the heating rate has a greater effect on increasing the yield of aliphatic and carbonyl compounds compared to that of aromatic compounds. The selectivity of the fast …
In Situ Infrared Study Of The Role Of Peg In Stabilizing Silica-Supported Amines For Co2 Capture, Jak Tanthana, Steven Chuang
In Situ Infrared Study Of The Role Of Peg In Stabilizing Silica-Supported Amines For Co2 Capture, Jak Tanthana, Steven Chuang
Steven S.C. Chuang
The CO(2) capture capacity, adsorption mechanism, and degradation characteristics of two sorbents, silica-supported tetraethylenepentamine (TEPA/SiO(2)) and polyethylene-glycol-modified TEPA/SiO(2) (PEG/TEPA/SiO(2)), are studied by diffuse reflectance infrared Fourier transform spectroscopy and mass spectrometry. The CO(2) capture capacities of TEPA/SiO(2) and PEG/TEPA/SiO(2) are determined to be 2087 and 1110 micromol CO(2) g(-1) sorbent, respectively. Both sorbents adsorb CO(2) as hydrogen-bonding species, NH(2)--O, and carbamate/carboxylate species. The CO(2) adsorption half-time increases with the number of CO(2) capture cycles. Infrared results suggest that the increased adsorption half-time is a result of diffusion limitation, caused by accumulation of TEPA and PEG species on the surface of …
In Situ Ir/Ms Study Of Partial Oxidation Of Ch4 Coupled With Pulse Technique Over Rh/Al2o3, Rahul Singh, Steven Chuang
In Situ Ir/Ms Study Of Partial Oxidation Of Ch4 Coupled With Pulse Technique Over Rh/Al2o3, Rahul Singh, Steven Chuang
Steven S.C. Chuang
Partial oxidation of methane was studied by pulsing O2 into a CH4 flow over Rh/Al2O3 in a sequence of in situ infrared (IR) cell and fixed bed reactor at 773 K. The results obtained from the sequence of an IR cell followed by a fixed bed reactor show that (i) adsorbed CO produced possesses a long residence time, indicating that adsorbed oxygen leading to the formation of CO is significantly different from those leading to CO2 and (ii) CO2 is not an intermediate species for the formation of CO. The results obtained from the reversed reactor sequence show the water–gas …
Analysis Of Gas Products From Direct Utilization Of Carbon In A Solid Oxide Fuel Cell, Tritti Seingchum, Felipe Guzman, Steven Chuang
Analysis Of Gas Products From Direct Utilization Of Carbon In A Solid Oxide Fuel Cell, Tritti Seingchum, Felipe Guzman, Steven Chuang
Steven S.C. Chuang
The evolution of gases from direct utilization of carbon in a solid oxide fuel cell (C-SOFC) was studied by potentiostatic/galvanostatic discharge of a fuel cell with coconut carbon, a carbonaceous material with low ash and sulfur content. Operation of C-SOFC at 750 °C produced less CO and more CO2 than those predicted by thermodynamic calculation using total Gibbs free energy minimization method. The addition of CO2 to the anode chamber increased CO formation and maximum power density from 0.09 W cm−2 to 0.13 W cm−2, indicating the occurrence of Boudouard reaction (CO2 + C ⇔ 2CO) coupling with CO electrochemical …
Spectroscopic Investigation Into Oxidative Degradation Of Silica-Supported Amine Sorbents For Co2 Capture, Chakravartula Srikanth, Steven Chuang
Spectroscopic Investigation Into Oxidative Degradation Of Silica-Supported Amine Sorbents For Co2 Capture, Chakravartula Srikanth, Steven Chuang
Steven S.C. Chuang
Oxidative degradation characteristics of silica-supported amine sorbents with varying amounts of tetraethylenepentamine (TEPA) and polyethylene glycol (PEG; P200 or P600 represents PEG with molecular weights of 200 or 600) have been studied by IR and NMR spectroscopy. Thermal treatment of the sorbents and liquid TEPA at 100 °C for 12 h changed their color from white to yellow. The CO2 capture capacity of the TEPA/SiO2 sorbents (i.e., SiO2-supported TEPA with a TEPA/SiO2 ratio of 25:75) decreased by more than 60 %. IR and NMR spectroscopy studies showed that the yellow color of the degraded sorbents resulted from the formation of …
Catalysis Of Solid Oxide Fuel Cells, Steven Chuang
Catalysis Of Solid Oxide Fuel Cells, Steven Chuang
Steven S.C. Chuang
Solid oxide fuel cells (SOFCs) and solid oxide electrolyzers (SOEs) hold much promise as highly efficient devices for the direct interconversion of chemical and electrical energy. Commercial application of these devices, however, requires further improvements in their performance and stability. Because the performance of SOFC and SOE electrodes depends on their microstructures, electronic and ionic conductivities, and chemical reactivities, the needed improvements require the expertise of various disciplines, with catalytic science playing an important role. Highly active and thermally stable catalysts are required to limit the internal losses in the devices, increase the range of fuels they can use, and …
Probing Methylene Blue Photocatalytic Degradation By Adsorbed Ethanol With In Situ Ir, Zhiqiang Yu, Steven Chuang
Probing Methylene Blue Photocatalytic Degradation By Adsorbed Ethanol With In Situ Ir, Zhiqiang Yu, Steven Chuang
Steven S.C. Chuang
The dynamic behavior of infrared (IR)-observable species during the methylene blue [i.e., MB, (CH3)2N(C6H3)NS+(C6H3)N(CH3)2Cl-] photocatalytic degradation (PCD) on TiO2 has been investigated at 30 °C. Exposure of MB/TiO2 to UV illumination led to the scission of the N−CH3 bond followed by breaking of the C−H and CN bonds in the MB central aromatic ring and the side aromatic rings, indicating demethylation as the first step of the MB PCD. The bond breaking in the MB molecule and subsequent reactions produced charge-containing intermediates (i.e., carboxylate (RCOO-) and R−NH3+), slowing down the conversion of MB to CO2, H2O, NH4+, and SO42-. Probing …
Thermal And Chemical Stability Of Regenerable Solid Amine Sorbent For Co2 Capture, Rajesh Khatri, Steven Chuang, Yee Soong, Mcmahan Gray
Thermal And Chemical Stability Of Regenerable Solid Amine Sorbent For Co2 Capture, Rajesh Khatri, Steven Chuang, Yee Soong, Mcmahan Gray
Steven S.C. Chuang
The adsorption and desorption of CO2 and SO2 on an amine-grafted SBA-15 sorbent has been studied by in situ infrared spectroscopy coupled with mass spectrometry. CO2 adsorbed on an amine-grafted sorbent as carbonates and bicarbonates, while SO2 adsorbed as sulfates and sulfites. The CO2 adsorption capacity of the amine-grafted sorbent was almost twice as much as that of a commercial sorbent. The adsorption of CO2 in the presence of H2O and D2O shows an isotopic shift in the IR frequency of adsorbed carbonate and bicarbonate bands, revealing that water plays a role in the CO2 adsorption on amine-grafted sorbents. Although …
Co2 Capture By Amine-Enriched Fly Ash Carbon Sorbents, Steven Chuang, M. Gray, Y. Soong, K. Champagne, John Baltrus, R. Stevens, P. Toochinda
Co2 Capture By Amine-Enriched Fly Ash Carbon Sorbents, Steven Chuang, M. Gray, Y. Soong, K. Champagne, John Baltrus, R. Stevens, P. Toochinda
Steven S.C. Chuang
The capture of CO2 from gas streams has been achieved by the utilization of amine-enriched fly ash carbon sorbent system. The initial fly ash carbon sorbents were generated by the chemical treatment of carbon-enriched fly ash concentrates with a 3-chloropropylamine-hydrochloride (CPAHCL) solution at 25 °C. It was determined that these amine-enriched fly ash carbon sorbents performed at a 9% CO2 capture capacity based on commercially available sorbents. The chemical sorption performance of these amine-enriched fly ash carbon sorbents will be described within this paper.
Static And Dynamic Hydrogen Adsorption On Pt/Ac And Mof-5, Andrew Chien, Steven Chuang
Static And Dynamic Hydrogen Adsorption On Pt/Ac And Mof-5, Andrew Chien, Steven Chuang
Steven S.C. Chuang
Hydrogen adsorption has been studied by static and dynamic methods on activated carbon (AC), platinum/activated carbon (Pt/AC), metal organic frameworks (MOF-5), and Pt/AC_MOF-5.The static method showed that all of adsorbents used in this study exhibited a Langmuir (type I) adsorption isotherm at 77 K and a linear function of hydrogen partial pressure at 298 K. The dynamic method produced breakthrough curves, indicating (i) slow rate of hydrogen diffusion in the densely packed activated carbon and Pt/AC beds and (ii) high rate of hydrogen diffusion in the loosely packed bed with large MOF-5 crystallites. Temperature variable adsorption resulted in the higher …
Effect Of Gas Flow Rates And Boudouard Reactions On The Performance Of Ni/Ysz Anode Supported Solid Oxide Fuel Cells With Solid Carbon Fuels, Andrew Chien, Steven Chuang
Effect Of Gas Flow Rates And Boudouard Reactions On The Performance Of Ni/Ysz Anode Supported Solid Oxide Fuel Cells With Solid Carbon Fuels, Andrew Chien, Steven Chuang
Steven S.C. Chuang
The effects of carrier gas flow rates and Boudouard reaction on the performance of Ni/YSZ anode-supported solid oxide fuel cells (SOFCs) have been studied with coconut coke fuels at 800 °C. Decreasing flow rates of carrier gas from 1000 to 50 ml min−1 increased open circuit voltages and current densities from 0.71 to 0.87 V and from 0.12 to 0.34 A cm−2, respectively. The increased cell performance was attributed to the increasing extent of electrochemical oxidation of CO, a product of Boudouard reaction. The contribution of CO oxidation to current generation was estimated to 66% in flowing inert carrier gas …
Investigating The Ch 4 Reaction Pathway On A Novel Lscf Anode Catalyst In The Sofc, James Fisher, Steven Chuang
Investigating The Ch 4 Reaction Pathway On A Novel Lscf Anode Catalyst In The Sofc, James Fisher, Steven Chuang
Steven S.C. Chuang
For the first time, the perovskite lanthanum strontium cobalt ferrite (LSCF) is demonstrated to exhibit catalytic activity for the direct electrochemical oxidation of CH4 in a solid oxide fuel cell (SOFC) anode environment for more than 72 h with a steady state flow of CH4 at 900 °C, producing a maximum of 186 W/cm2. Results of the transient response studies suggested that the electrochemical oxidation of CH4 on the anode produced electricity, H2O, and CO2 via (i) CH4 decomposition, (ii) electrochemical oxidation of hydrogen to H2O, and (iii) electrochemical oxidation of carbon to CO2. The formation of CO2 and CO …
Carbon Dioxide Capture By Diamine-Grafted Sba-15: A Combined Fourier Transform Infrared And Mass Spectrometry Study, Rajesh Khatri, Steven Chuang, Yee Soong, Mcmahan Gray
Carbon Dioxide Capture By Diamine-Grafted Sba-15: A Combined Fourier Transform Infrared And Mass Spectrometry Study, Rajesh Khatri, Steven Chuang, Yee Soong, Mcmahan Gray
Steven S.C. Chuang
The adsorption and desorption of CO2 on diamine-grafted SBA-15 have been studied by infrared spectroscopy coupled with mass spectrometry. Diamine was grafted onto the SBA-15 surface by the reaction of [N-(2-aminoethyl)-3-aminopropyl]trimethoxysilane with the surface OH. CO2 is adsorbed on the diamine-grafted SBA-15 as bidentate carbonate and bidentate and monodentate bicarbonates at 25 °C. Bidentate carbonate and monodentate bicarbonates are the major surface species formed and decomposed during the concentration-swing adsorption/desorption process at 25 °C. Temperature-programmed desorption revealed that the monodentate and bidentate bicarbonates bound stronger to the diamine-grafted SBA-15 surface than the bidentate carbonate. The amount of CO2 desorbed from …
Tracing The Reaction Steps Involving Oxygen And Ir Observable Species In Ethanol Photocatalytic Oxidation On Tio2, Felipe Guzman, Steven Chuang
Tracing The Reaction Steps Involving Oxygen And Ir Observable Species In Ethanol Photocatalytic Oxidation On Tio2, Felipe Guzman, Steven Chuang
Steven S.C. Chuang
The rate-determining step of ethanol photocatalytic oxidation was identified to be the adsorption of O2 by an infrared (IR) spectroscopy coupled with mass spectrometry method. Dosing O2 during reaction showed that adsorption of O2 controls the accumulation of photogenerated electrons and the formation of acetate (CH3COO−ad), acyl species (CH3COad), acetaldehyde (CH3CHOad), CO2, and H2O. Accumulation of CH3COO−ad on the TiO2 surface slowed down the conversion of ethanol to CO2 and H2O. Removal of CH3COO−ad from the TiO2 surface holds the key to accelerating the rate of ethanol photocatalytic oxidation. This study bridges the gap between results of nanosecond and millisecond …
Oxide-Supported Tetraethylenepentamine For Co2 Capture, James Fisher, Jak Tanthana, Steven Chuang
Oxide-Supported Tetraethylenepentamine For Co2 Capture, James Fisher, Jak Tanthana, Steven Chuang
Steven S.C. Chuang
CO2 capture capacity of tetraethylenepentamine (TEPA) supported on beta zeolite, SiO2, and Al2O3 has been studied by transient flow switching approach and temperature programmed desorption (TPD) technique coupled with diffuse infrared reflectance Fourier transform spectroscopy and mass spectrometry (MS). TEPA/beta zeolite shows the highest CO2 capture capacity. Adsorbed CO2 on TEPA/beta zeolite can be characterized as weakly and strongly adsorbed CO2. The former desorbs when CO2 partial pressure decreases; the latter desorbs during TPD. Strongly adsorbed CO2 is in the form of carbonates interacting with the NH functional groups of TEPA. This interaction caused the NH and CH intensity to …
Direct Use Of Sulfur-Containing Coke On A Ni- Yttria-Stabilized Zirconia Anode Solid Oxide Fuel Cell, Felipe Guzman, Rahul Singh, Steven Chuang
Direct Use Of Sulfur-Containing Coke On A Ni- Yttria-Stabilized Zirconia Anode Solid Oxide Fuel Cell, Felipe Guzman, Rahul Singh, Steven Chuang
Steven S.C. Chuang
The direct use of sulfur-containing coke to generate electricity has been studied by a transient approach that involves feeding a batch of coke samples to a Ni−yttria-stabilized zirconia (YSZ) anode solid oxide fuel cell operating at 750 °C in flowing He, measuring the fuel cell performance, and monitoring the concentration of the exhaust gases with a mass spectrometer (MS) and a gas chromatograph (GC). Feeding coke to the fuel cell produced current densities as high as 261 mA/cm2 at a load of 0.56 V with the concomitant evolution of CO2, giving an energy efficiency (i.e., the ratio of the electric …
In Situ Ir Study Of Transient Co2 Reforming Of Ch4 Over Rh/Al2o3, Steven Chuang, Robert Stevens
In Situ Ir Study Of Transient Co2 Reforming Of Ch4 Over Rh/Al2o3, Steven Chuang, Robert Stevens
Steven S.C. Chuang
The CO2−CH4 reaction on Rh/Al2O3 was studied by in situ infrared spectroscopy coupled with pulse and step transient techniques. Steady-state isotopic 13CO transient studies at 773 K and 0.1 MPa show that the formation of gaseous 13CO2 closely follows that of linear 13CO, indicating that linear CO is an active adsorbate. Pulsing CH4 into CO2 flow and step switching from He to CO2/CH4 flow showed that the formation of H2 led that of CO, revealing that the first step of the reaction sequence is the decomposition of CH4 into *CHx species and hydrogen. Hydrogen activated adsorbed CO2 to produce linear …
Performance And Byproduct Analysis Of Coal Gas Solid Oxide Fuel Cell, Rahul Singh, Felipe Guzman, Rajesh Khatri, Steven Chuang
Performance And Byproduct Analysis Of Coal Gas Solid Oxide Fuel Cell, Rahul Singh, Felipe Guzman, Rajesh Khatri, Steven Chuang
Steven S.C. Chuang
The direct electrochemical oxidation of coal gas was studied by pyrolyzing a sample of Ohio #5 coal in flowing Ar at 700, 800, 900, and 950 °C and transporting the resulting gaseous products to a Cu (Copper) anode solid oxide fuel cell (SOFC) operated at 950 °C. Pyrolysis of coal at 700 °C produced a H2-rich coal gas containing 89% H2, 4% CO, 6% CH4, 1% CO2, and sulfur compounds (i.e., 1% COS and 1% SO2), which yielded a maximum current density of 320 mA/cm2 at 0.5 V. Raising the pyrolysis temperature from 700 to 950 °C increased the CO …
Mechanism Of C 2+ Oxygenate Synthesis On Rh Catalysts, Steven Chuang, Robert Stevens, Rajesh Khatri
Mechanism Of C 2+ Oxygenate Synthesis On Rh Catalysts, Steven Chuang, Robert Stevens, Rajesh Khatri
Steven S.C. Chuang
This paper examines the reaction pathways and the nature of active sites for CO hydrogenation in general and C2+ oxygenate synthesis over Rh catalysts in particular.
Improved Immobilized Carbon Dioxide Capture Sorbents, M. Gray, Y. Soong, K. Champagne, H. Pennline, J. Baltrus, R. Stevens, R. Khatri, Steven Chuang, T. Filburn
Improved Immobilized Carbon Dioxide Capture Sorbents, M. Gray, Y. Soong, K. Champagne, H. Pennline, J. Baltrus, R. Stevens, R. Khatri, Steven Chuang, T. Filburn
Steven S.C. Chuang
The capture of carbon dioxide from simulated flue gas streams has been achieved by using immobilized and aminated-SBA-15 solid sorbents. SBA-15, a mesoporous silica material with a uniform pore size of 21 nm and a surface area of 200∼230 m2/g. The solid sorbents prepared in this study exhibit similar or improved capacities relative to those already used to control CO2 concentrations in submarine and spacecraft applications. The results suggest that immobilized secondary amines have a stronger affinity for the capture of carbon dioxide from simulated flue gas streams than primary amines. The performance of these immobilized and aminated-SBA-15 solid sorbents …
In Situ Infrared Study Of No Reduction Over Pd/Al2o3 And Ag-Pd/Al2o3 Catalysts Under H2 Rich And Lean-Burn Conditions, Duane Miller, Steven Chuang
In Situ Infrared Study Of No Reduction Over Pd/Al2o3 And Ag-Pd/Al2o3 Catalysts Under H2 Rich And Lean-Burn Conditions, Duane Miller, Steven Chuang
Steven S.C. Chuang
Catalytic reduction of NO under H2-rich and lean-burn conditions over Pd/Al2O3 and Ag-Pd/Al2O3 has been studied by temperature programmed reaction (TPR) coupled with in situ infrared (IR) and mass spectrometry (MS) techniques. Under H2-rich conditions, Pd/Al2O3 produces, Pd-NCO, Pd+-NO, Pd0-NO, and adsorbed nitrate at temperatures below 398 K. N2 and adsorbed NH3 are produced at temperatures above 400 K. Addition of Ag to Pd/Al2O3 suppresses the Pd+-NO formation and lowers the formation temperature of NH3 species to 373 K. Under lean-burn conditions, Pd/Al2O3 produces Pd-NCO, Pd+-NO, Pd0-NO, and adsorbed nitrate at temperatures below 373 K, while the addition of Ag …
Pulse Transient Responses Of No Decomposition And Reduction With H2 On Ag- Pd/Al2o3, Duane Miller, Steven Chuang
Pulse Transient Responses Of No Decomposition And Reduction With H2 On Ag- Pd/Al2o3, Duane Miller, Steven Chuang
Steven S.C. Chuang
Catalytic decomposition of nitric oxide (NO) over Pd/Al2O3 and Ag−Pd/Al2O3 has been studied using the pulse transient response technique coupled with in situ infrared (IR) and mass spectrometry (MS) at 723−823 K. In the absence of H2, pulsing NO over the Pd/Al2O3 catalyst produces adsorbed NO species (i.e., Pd+−NO, Pd0−NO, and Pd−NO−) as well as gaseous N2, O2, and N2O products. Transient responses of the N2 and O2 profiles show that the addition of Ag onto Pd/Al2O3 catalyst shifts the O2 profile forward, increases oxygen formation and the oxidation resistance of Pd, but did not decrease the amount of retained …
Silica-Supported Amine Catalysts For Carbon--Carbon Addition Reactions, Ernesto Silva, Srikanth Chakravartula, Steven Chuang
Silica-Supported Amine Catalysts For Carbon--Carbon Addition Reactions, Ernesto Silva, Srikanth Chakravartula, Steven Chuang
Steven S.C. Chuang
Basic catalysts for carbon–carbon addition reactions were synthesized by immobilization of amine species on silica supports. Tetraethylenepentamine was impregnated and immobilized on amorphous silica (SiO2) and SBA-15 using an epoxy resin. The basicity of the catalysts was determined by adsorption–desorption of CO2 and the degree of immobilization was evaluated by FTIR. The catalytic activity towards the Claisen condensation reaction of methyl benzoate and methyl ethyl ketone was evaluated by an in-situ FTIR micro-scale reactor. A mechanism is proposed to show that the catalysts promote the formation of β-diketone and methanol; the effects of the support and amine immobilization degree are …
The Effect Of Pt On The Photocatalytic Degradation Pathway Of Methylene Blue Over Tio2 Under Ambient Conditions, Zhiqiang Yu, Steven Chuang
The Effect Of Pt On The Photocatalytic Degradation Pathway Of Methylene Blue Over Tio2 Under Ambient Conditions, Zhiqiang Yu, Steven Chuang
Steven S.C. Chuang
Photocatalytic degradation pathway of methylene blue (MB) has been studied over TiO2, 0.5 wt.% Pt/TiO2, and 3 wt.% Pt/TiO2 at ambient conditions (30 °C and 1 atm of air) by infrared (IR) spectroscopy. The reaction was proposed to be initiated via the abstraction of H from MB molecule by hydroxyl radical (·OH), followed by –CH3 elimination and CAr–N scission. The correlation in IR intensity between the decrease in C–H bond in MB molecule and the increase in hydroxyl group (–OH) at 3672 cm−1 during the reaction (i) provides an indirect evidence to support the proposed ·OH-initiating pathway, (ii) suggests that …
Pulse Ch 4/D 2o Reaction On A Ni/Ysz Anode In Sofc, Zhiqiang Yu, Steven Chuang
Pulse Ch 4/D 2o Reaction On A Ni/Ysz Anode In Sofc, Zhiqiang Yu, Steven Chuang
Steven S.C. Chuang
The activity and coking characteristics of a nickel/yttrium stabilized zirconia (Ni/YSZ) anode in a YSZ electrolyte/LSM cathode fuel cell have been investigated by steady state H2 as well as pulse CH4 and D2O/CH4 reactions. Pulse CH4 reaction produced H2, CO and carbon deposits (i.e., coke); pulse D2O/CH4 reaction led to the formation of H2, HD, D2 and CO under the open circuit condition where O2− was not able to diffuse across the YSZ membrane. Closing the circuit allowed O2− to diffuse across the YSZ membrane from the lanthanum strontium manganate (LSM) cathode to the Ni/YSZ anode, leading to oxidation of …
Mechanistic Investigation Of Heterogeneous Catalysis By Transient Infrared Methods, Steven Chuang, Felipe Guzman
Mechanistic Investigation Of Heterogeneous Catalysis By Transient Infrared Methods, Steven Chuang, Felipe Guzman
Steven S.C. Chuang
This paper provides an overview of the use of various transient infrared methods to determine the role of infrared observable species in the mechanisms of the NO–CO reaction, heterogeneous ethylene hydroformylation, and photocatalytic oxidation of ethanol. The transient infrared methods with a judicious choice of ways in changing the concentration of reactants and their isotope counterparts produce responses, allowing (i) identification of the spectators, (ii) determination of active adsorbed species, and (iii) verification of kinetic models and their parameters. The method has also been recently extended to monitor infrared absorbance of photogenerated electrons during photocatalysis, correlating variation in the concentration …
The Effect Of O2 On The No--Co Reaction Over Ag--Pd/Al2o3: An In Situ Infrared Study, Steven Chuang
The Effect Of O2 On The No--Co Reaction Over Ag--Pd/Al2o3: An In Situ Infrared Study, Steven Chuang
Steven S.C. Chuang
The effect of O2 on the NO–CO reaction over Pd/Al2O3 and Ag–Pd/Al2O3 has been studied by in situ infrared (IR) spectroscopy coupled with the O2 pulse technique at 373–573 K. Pulsing O2 into the NO–CO flow at 373 K causes the oxidation of Pd+–NO to gaseous NO2 over Pd/Al2O3 and the emergence of Pd0–NO on Ag–Pd/Al2O3. The formation of Pd0–NO during the O2 pulse over Ag–Pd/Al2O3 catalyst suggests that (i) O2 disrupts the Ag overlayers on the Pd surface, allowing the Pd surface to be exposed to NO; and (ii) Ag species is able to keep the Pd surface in …