Catalysis and catalyst is a key technology to solve the problems in
energy and environment issues to sustain our human society. We believe
that comprehensive understanding of the catalysis and catalyst provides
us a chance to develop a new catalyst and contributes greatly to our
society. However, the ?eld of heterogeneous catalyst is dif?cultto study
andstill stays behindmoredeveloped?elds ofchemistry such as organic and
physical chemistries. This is a dilemma to the chemists who study the
catalysis and catalyst. While we can accomplish the progress in the -
dustrial application, the scienti?c understandingis not complete yet. A
gap between the useful application and incomplete scienti?c
understanding, however, becomes smaller and smaller in recent years.
Because zeolites are ?ne crystals, and the structure is clearly known,
the study on the catalysis using the zeolites is easier than those
encountered in other catalysts such as metals and metal oxides. Very
fortunately, zeolites provide us the strong acidity with the ?ne
distribution which enables various useful catalytic reactions. When some
metals and cations are loaded in close to the acid sites, these loadede-
ments show extraordinarycharacters, and many catalytic reactions proceed
thereon.