摘要:

This review has been structured to provide a bridge between the fields of electrocatalysis and gas-phase catalysis on solid surfaces. Considerable emphasis has been placed upon the characterization of adsorbed species on electrocatalysts. Electrocatalytic studies show surface interactions between adsorbed CO and H on Pt, which parallel similar studies in the gas phase.

ISSN:0161-4940    

DOI:10.1080/01614947508067520

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

The advent of enzyme immobilization, allowing re-use of enzymes, and essentially eliminating product contamination, has greatly increased the potential of enzymatic processes for industrial use. Although this is a relatively new field of study, the literature is rapidly expanding. The compendium of references prepared by the New England Research Applications Center for Corning Glass Works now lists over 800 papers concerning immobilized enzymes. For this reason the scope of this paper is limited to immobilized enzyme engineering, including reactor design and performance. Although medical and analytical applications of immobilized enzymes are important, they will not be discussed as such here. Another large body of information concerning enzyme immobilization techniques will be treated only briefly as an introduction. Other general articles and reviews [1–5] may be useful in providing additional background information.

ISSN:0161-4940    

DOI:10.1080/01614947508067521

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

This paper discusses the surface order-dependent adsorptive activity at the surfaces of tetrahedrally coordinated semiconductors. It stresses the differences between elemental (e.g., Si) and compound materials (e.g., Gas, CdS, and ZnO) as well as the differences between ordered and disordered nonpolar compound semiconductor surfaces. Several examples will be presented that compare oxygen adsorption on ordered and disordered surfaces. It will be shown that adsorption on ordered nonpolar compound semiconductor surfaces is weak in comparison to adsorption on ordered elemental semiconductor surfaces, that among the compound semiconductors the ordered nonpolar surfaces of the II-VI materials (e.g.,) are much weaker adsorbents than the similar surfaces of the III-V materials (e.g., GaAs), and that adsorption on nonpolar compound semiconductor surfaces is much enhanced by surface disorder. It will be argued that these phenomena can collectively be attributed to bonding ionicity. Finally, an attempt will be made to establish a connection between the order/disorder phenomena described here and the collective electronic and active site models of surfaceactive catalysis.

ISSN:0161-4940    

DOI:10.1080/01614947508067522

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

Metal catalysts are commonly employed in the form of metal dispersed as small crystallites on high surface area supports. The use of these supported metal catalysts increases the utilization of the metal as a catalyst since a large fraction of the metal atoms are at the surface of the small metal crystallites. Another important function of the support is to physically separate the small metal crystallites and thereby hinder the agglomeration of the small metal crystallites into larger crystallites. This agglomeration would decrease the number of surface metal atoms per unit mass of metal, and thereby decrease the utilization of the metal and the activity of the catalyst.

ISSN:0161-4940    

DOI:10.1080/01614947508067523

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

The chemistry of transition metal complexes in zeolites has received considerable attention in our laboratory because we believe that such complexes have potential both in fundamental and applied catalysis. To scientists outside of the field of heterogeneous catalysis it often appears virtually hopeless to obtain meaningful chemistry from surface reactions because the active centers are so poorly characterized. Although most catalytic chemists would not totally agree with this viewpoint, one would have to admit that it contains an element of truth. The traditional approach to solving this problem has been to attempt better characterization of active sites on known catalysts, and while some significant advances have been made in this direction, the progress in general has been painfully slow. Another approach, and the one which will be described here, has been to synthesize surface complexes which are both well defined and active as catalysts. These then may serve as model systems for conventional catalysts, but more than this, they may be unique catalysts which are important in their own right.

ISSN:0161-4940    

DOI:10.1080/01614947508067524

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

The use of spectroscopic techniques in the study of catalysts is rapidly increasing and has given a stimulus to research in catalysis. All techniques, however, are of restricted applicability; for example, ESR, NMR, reflection spectroscopy, and X-ray electron spectroscopy. Often a number of techniques have to be applied to give the full answer to a problem. The same is true for the technique under discussion in this paper. Luminescence spectroscopy can be helpful for a certain number of systems but is far from being generally applicable. It is, however, specific in the sense that it can solve certain problems, especially in oxidic catalysts, which are very difficult to solve with other techniques.

ISSN:0161-4940    

DOI:10.1080/01614947508067525

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

Catalytic processes on solid catalysts dominate among large-scale operations in chemical and petrochemical industry.

ISSN:0161-4940    

DOI:10.1080/01614947508067526

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

In 1970 Merrill reviewed the application of molecular beams to studies of gas-surface interactions related to catalysis [1]. Since that time there has been a rather impressive increase in the number of experimental studies in this area. More recently, Saltsburg has reviewed the dynamical aspects of gas-surface collisions, with some emphasis on beam experiments [2]. The latest advances in experimental techniques in molecular beam studies of reactive scattering and heterogeneous catalysis have been reviewed by Smith [3] and most recently by Madix [4]. The purpose of this review is to present both a comprehensive survey of the experimental work that has been reported subsequent to the review by Merrill and to focus critical attention on what is felt to be the more significant features of this work. While our first intent can be carried out rather objectively, we have chosen to focus on those aspects of the work that relate more closely to our own research.

ISSN:0161-4940    

DOI:10.1080/01614947508067527

出版商:Taylor & Francis Group    

年代:1975

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:10.1080/01614947508067519

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor