Parravano

G. Parravano and M. Boudart The Compensation Effect in Heterogeneous Catalysis E. Cremer... 

Sea Water. The analysis of seawater (Parravano, C., State University of New York at Purchase Steams, C., unpublished) is a three-part experiment employing ion exchange techniques titrations to study the salt content of this familiar... 

Thus, there is excess of zinc over that required by stoichiometry. Sintering was attributed by Lee Parravano (1959) to the diffusion of Zn ions consequent on the difference in concentration of excess Zn " ions between the surface and the bulk. 

Lee, V. J. Parravano, G. (1959). Sintering reactions on zinc oxide. Journal of Applied Physics, 30, 1735-40. 

Molinari and Parravano (30) have also noted that the incorporation of a donor impurity (Al, Ga) into ZnO specimens promotes the exchange reaction, while an acceptor impurity (Li) slows it down. 

Note that the impurities exert opposite influences on the reaction in the dark. The oxidation of CO, like any acceptor reaction, is retarded by acceptor impurities (increase of tB ) and accelerated by donor impurities (decrease of e3 ). As a matter of fact, according to Parravano s data (61)... 

It should be noted in passing that according to Schwab and Block (63) Li added to NiO in the dark reaction of oxidation of CO acts not as a poison, as follows from (61) and (62) and from theory, but as a promoter. This contradiction between the data obtained by Parravano and Keier, Roginsky, and Sazonova, on the one hand, and those of Schwab and Block, on the other, may have a dual origin. 

In any case, going back to the beginning of the past century we may mention the pioneering investigation carried out by Parravano and Sirovich (1912) and Parravano (1914) in the determination by thermal analysis of the phase diagrams of quaternary alloy systems, such as Cu-Fe-Mn-Ni, Bi-Cd-Pb-Sn, Ag-Au-Cu-Ni. 

Witzel, F Sill, GA Hall, WK. The selective reduction of NO and combustion of paraffins over MFI zeolites. Stud. Surf. Sci. Catal, 1994, Volume 84, 1531-1536. Parravano, G. Ferroelectric transitions and heterogenous Catalysis, J. Chem. Phys., 1952, Volume 20,342-343. 

This reaction which takes place both on n-type (for example, on ZnO) and on p-type (for example, NiO) semiconductors has been thoroughly studied by numerous authors. (A summary is given, for example, in the paper by Takaishi 31 and in the book by Germain, 33.) It should be noted that the results of different authors often disagree with one another. (Compare, for example, the results of Schwab and Block, 33, an electronic interpretation of which was attempted by Hauffe and Schlosser, 34, with the results of Parravano, 35, and Keyer et aL, 36.)... 

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