摘要:

The stark realization in recent times that the earth's fossil fuel resources do not represent an inexhaustible supply of fuel to meet society's energy needs has prompted the investigation of many alternative fuel sources. One of these is water splitting which, when combined with solar or nuclear heat sources, provides a renewable portable fuel from water in the form of hydrogen, which can be stored as a gas, liquid, or hydride depending on the application, The benefits of going to a hydrogen economy appear to be many, and in recent years various researchers around the world have devoted considerable effort to developing a viable process for economic large-scale production of hydrogen fuel from water.

ISSN:0161-4940    

DOI:10.1080/03602458008067537

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

Catalytic effects of Mo and W compounds in various chemical reactions have been known for decades. Supported catalysts containing Mo or W components as essential active ingredients are the most widely used catalysts in refinery practice. In spite of this, the forms of active Mo or W species and their intimate roles in catalytic reactions are not well understood, Although the presence of sulfides such as MoS2and WS2is frequently reported in these materials, their participation in catalytic reactions is a matter of speculation. In recent years, significant progress has been made in this respect as the result of applying modern techniques, particularly spectroscopy.

ISSN:0161-4940    

DOI:10.1080/03602458008067538

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

The structural chemistry of Co-Mo-alumina hydrodesulfurization catalysts has been critically reviewed in this article. The location and nature of cobalt in the sulfided catalysts has been discussed. Small MoS2, crystallites (10 to 30 Å) that occur on the surface of a sulfided sample are unstable due to the high, net negative charge on the sulfur ions on their edges. They incorporate cations like Co2+ at the edges of the MoS2sheet (not intercalated between the sheets) and attain stability. It is shown that for the range of crystallito sizes of MoS, in these systems, a maximum of one Co ion can be incorporated per two Mo ions in this manner. Cobalt thus lends structural stability to the MoS2, crystallites and suppresses the excessive formation of anion vacancies at crystallite edges. Molybdenum sulfide crystallites on sulfided Mo-A12O3, lacking this stabilizing influence of cobalt, lose excess sulfur, leading to the creation of a larger concentration of multiple anion vacancies at their edges. The presence of these strongly acidic multiple vacancies, however, leads to a lower structural stability of these crystallites. Moreover, these strongly acidic sites are also deactivated faster in the presence of unsaturated molecules (like diolefins, olefins, etc.), accounting for the fact that the superiority of Co-Mo-Al2O3over Mo-Al2O3manifests itself mainly in the steady-state activity [61–63].

ISSN:0161-4940    

DOI:10.1080/03602458008067539

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

Packed bed reactors are commonly used for carrying out heterogeneous chemical reactions, and the attendant complexities arising out of the interactions of the momentum, heat, and mass transport processes make the design of such units a very involved and cumbersome task. The strategy for rational design depends strongly on the nature of the reaction scheme and its sensitivity to perturbations in operating conditions. Models ranging from simple one-dimensional pseudohomogeneous to two-dimensional heterogeneous are used to describe process behavior. Reviews detailing these aspects of the packed-bed have appeared from time to time.

ISSN:0161-4940    

DOI:10.1080/03602458008067540

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

This is a scanned image of the original Editorial Board page(s) for this issue.

ISSN:0161-4940    

DOI:10.1080/03602458008067536

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor