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BACKGROUND
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Spatially
structured systems, extensively represented in biology, play a significant
growing role also in chemistry, catalysis and chemical technology. From the
scientific viewpoint the ability to replace the random structures and processes
with the ordered ones presents a highly challenging issue, with application
potential extending from material engineering and precision technology to
the life sciences and medicine.
Structured catalysts and reactors appear to be one of the most significant
and promising developments in the field of heterogeneous catalysis and chemical
engineering of the recent years.
They have already found numerous applications ranging from car afterburners
(this way monolithic converters became the most widespread type of catalytic
reactors) to large-scale chemical technologies for environmental protection.
In order to comply with the current and upcoming polluting emissions regulations
for Diesel vehicles, the automotive industry nowadays relies on innovative
oxidative and deNOx structured catalytic converters, integrated with particulate
filters.
Structured catalysts can also greatly intensify chemical processes, resulting
in smaller, safer, cleaner and more energy efficient technologies. Multifunctional
reactors, in which chemical conversion is advantageously integrated with another
unit operation, are largely based on structured catalytic systems, such as
open crossflow catalysts for reactive distillation units or catalytic membranes
for membrane reactors. Microreactors are another area of growing interest
which relies on structuring of catalysts.