Stoichiography as applied to studying composition and real structure of catalysts

The general principles of a new concept of chemical analysis, called stoich iography, are represented. Stoichiography allows the reference-free analyzi ng of the molecular and phase composition of complex substances. The differ ential dissolving technique as a new stoichiography method was developed to characterize in detail the phase composition of heterogeneous catalysts an d to identify known and absolutely unknown phases composing the catalyst. T he analyzed phases may be in crystalline or amorphous state, which is of no importance for the analysis performance. Such phase analysis is performed with a high sensitivity and very fast. Equipment, developed specially for t his analysis, is called stoichiograph. The advantages of differential disso lving in studying the phase composition of catalysts are demonstrated throu gh many particular examples. (C) 2000 Elsevier Science B.V. All rights rese rved.