A bifunctional catalyst for the single-stage water–gas shift reaction in fuel cell applications. Part 2. Roles of the support and promoter on catalyst activity and stability

Azzam, Khalid G.; Babich, Igor V.; Seshan, Kulathuiyer; Lefferts, Leon

doi:10.1016/j.jcat.2007.07.011

Cited by 120 publications

(131 citation statements)

References 47 publications

Supporting

Mentioning

123

Contrasting

Unclassified

Order By: Relevance

“…On this catalyst, ethanol was first dehydrogenated to acetaldehyde and hydrogen by reaction (6), and at the lowest temperature (673 K), the rate of dehydrogenation was higher than that of reaction (7). With an increase in temperature, the selectivity to CO and CH 4 increased, indicating that the rate of decomposition of CH 3 CHO increased. The drop in selectivity to CO and the increase in the selectivity to CO 2 in the temperature range of 723-773 K indicated that the rate of WGS reaction increased.…”

Section: Steam Reforming Of Ethanolmentioning

confidence: 99%

See 1 more Smart Citation

Microstructured Reactors for Hydrogen Production from Ethanol

Peela

Kunzru

2015

Springer Tracts in Mechanical Engineering

View full text Add to dashboard Cite

The continuously increasing demand for clean and renewable energy warrants the development of renewable, nonpolluting energy resources. Hydrogen is emerging as a natural choice as a more secure and cleaner energy carrier. Fuel cells can be used to produce clean energy from hydrogen, particularly for portable applications. Hydrogen can be produced from a variety of fossil fuel sources, but to decrease the dependence on fossil fuels, hydrogen has to be produced from a renewable source. Hydrogen production from steam reforming of ethanol (a renewable fuel) has emerged as a promising alternative in recent years. For conducting this reaction on board a vehicle, a compact reactor system is required. A microchannel reactor is more efficient and attractive for this purpose, because of the high surface to volume ratio, resulting in high heat and mass transfer rates.The reactions involved in producing CO-free hydrogen from ethanol include steam reforming of ethanol, water-gas shift reaction, and preferential oxidation of carbon monoxide. This chapter discusses the steps involved in the development of a microfuel processor for producing hydrogen from ethanol that include fabrication of the microchannels on the metal substrate, coating of the catalyst and support on the microchannels, assembly of the microchannel reactor, optimization of the catalysts for the three reactions, and, finally, heat integration of the different processes to maximize the efficiency of the fuel processor.

show abstract

Section: Steam Reforming Of Ethanolmentioning

confidence: 99%

“…Azzam et al [4] measured the WGS activity of Pt supported on different oxides such as CeO 2 , ZrO 2 , CeO 2 -ZrO 2 , and TiO 2 . Out of these, Pt/CeO 2 was reported to be the most active.…”

Section: Water-gas Shift Reactionmentioning

confidence: 99%

Microstructured Reactors for Hydrogen Production from Ethanol

Peela

Kunzru

2015

Springer Tracts in Mechanical Engineering

View full text Add to dashboard Cite

show abstract

“…However, an equally well reported mechanism over TiO 2 catalysts is the associative route in which the reaction proceeds via the utilization of surface hydroxyl groups. [51][52][53] Azzam et al 21,22 have carried out pulse experiments on TiO 2 -based catalysts and have found the requirement of surface hydroxyl groups for the reaction to proceed. TGA studies on combustion synthesized TiO 2 have shown large concentration of surface hydroxyl groups.…”

Section: Structural Studiesmentioning

confidence: 99%

“…Several investigators including Lefferts and coworkers 21,22,55,56 have reported the possibility of utilization of oxide ion vacancies and the hydroxyl groups. The hydroxyl group formation and subsequent conversion to surface oxygen species was proposed.…”

Section: Structural Studiesmentioning

confidence: 99%

“…[12][13][14][15][16][17][18][19][20] Various surface reactions taking place over the catalyst are influenced by the identity of the support. Azzam et al 21,22 have reported the influence of the support on the path followed for WGS reaction over the Pt metal catalysts with various supports. The difference in the reducibility of the support was found to be responsible for the stabilization of the various intermediate species and, hence, different pathways were described during the reaction over the catalysts.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Support‐dependent activity of noble metal substituted oxide catalysts for the water gas shift reaction

Deshpande

Madras

2010

AIChE Journal

View full text Add to dashboard Cite

The water gas shift reaction was carried out over noble metal ion substituted nanocrystalline oxide catalysts with different supports. Spectroscopic studies of the catalysts before and after the reaction showed different surface phenomena occurring over the catalysts. Reaction mechanisms were proposed based upon the surface processes and intermediates formed. The dual site mechanism utilizing the oxide ion vacancies for water dissociation and metal ions for CO adsorption was proposed to describe the kinetics of the reaction over the reducible oxides like CeO 2 . A mechanism based on the interaction of adsorbed CO and the hydroxyl group was proposed for the reaction over ZrO 2 . A hybrid mechanism based on oxide ion vacancies and surface hydroxyl groups was proposed for the reaction over TiO 2 . The deactivation of the catalysts was also found to be support dependent. Kinetic models for both activation and deactivation were proposed.

show abstract

A mechanistic model for the water‐gas shift reaction over noble metal substituted ceria

2009

View full text Add to dashboard Cite

The water-gas shift (WGS) reaction was carried out in the presence of Pd and Pt substituted nanocrystalline ceria catalysts synthesized by solution combustion technique. The catalysts were characterized by powder XRD and XPS. The noble metals were found to be present in ionic form substituted for the cerium atoms. The catalysts showed high activity for the WGS reaction with high conversions below 250 C. The products of reaction were only carbon dioxide and hydrogen, and no hydrocarbons were observed even in trace quantities. The reactions were carried out with different amounts of noble metal ion substitution and 2% Pt substituted ceria was found to be the best catalyst. The various possible mechanisms for the reaction were proposed and tested for their consistency with experimental data. The dual site mechanism best described the kinetics of the reaction and the corresponding rate parameters were obtained.

show abstract

A bifunctional catalyst for the single-stage water–gas shift reaction in fuel cell applications. Part 2. Roles of the support and promoter on catalyst activity and stability

Cited by 120 publications

References 47 publications

Microstructured Reactors for Hydrogen Production from Ethanol

Microstructured Reactors for Hydrogen Production from Ethanol

Support‐dependent activity of noble metal substituted oxide catalysts for the water gas shift reaction

A mechanistic model for the water‐gas shift reaction over noble metal substituted ceria

Contact Info

Product

Resources

About