Figure 3 is an attempt to synthesize our collective knowledge of the influence of surface functionality on the activity of carbon-supported catalysts. Its roots can be traced to the incisive questions posed by Frank Derbyshire and his colleagues in Ref. 1, as well as to improved understanding of "the compatibility of the two chemical structures" . Apart from the effects of wetting and pore size distribution, carbon surface functionality governs the extent of adsorption of the catalyst precursor and the extent of its reduction or conversion to active state. Thus, for example, in catalyzing the oxygen transfer reactions illustrated here, the optimum surface chemistry is the one that (a) provides the anchoring sites for the catalyst precursor (e.g., carboxyl groups for ion exchange with cationic precursors), (b) allows favorable electrostatic interaction between the support and catalyst precursor (e.g., adsorption of anions at a pH less than the point of zero charge of the carbon), (c) prevents excessive catalyst mobility on the support surface, and (d) also facilitates the achievement of an intermediate oxidation state of the active phase, which in turn promotes oxygen transfer from the gas phase to the carbon surface. The two-tiered value of the Science Citation Index to researchers, as opposed to librarians and research administrators, has been demonstrated here. On one hand it provides a quick start in the evaluation of scientific impact of a peer-reviewed publication. On the other hand, its increased use along the lines suggested here will hopefully force us all to be more careful, more selective and more responsible in collecting the lists of references for our publications. Perhaps sometime soon this important, yet too often neglected, activity will again be regarded as an opportunity to give credit where credit is really due and not as a matter of convenience, tradition and even nuisance. Had this been the case with Ref. 1, its "objective impact" would have been much closer to the admittedly subjective but arguably more appropriate evaluation presented here.
|Number of pages
|ACS Division of Fuel Chemistry, Preprints
|Published - Dec 1 2000
All Science Journal Classification (ASJC) codes
- General Energy