A critical review of different prominent
nanotechnologies adapted
to catalysis is provided, with focus on how they contribute to the
improvement of selectivity in heterogeneous catalysis. Ways to modify
catalytic sites range from the use of the reversible or irreversible
adsorption of molecular modifiers to the immobilization or tethering
of homogeneous catalysts and the development of well-defined catalytic
sites on solid surfaces. The latter covers methods for the dispersion
of single-atom sites within solid supports as well as the use of complex
nanostructures, and it includes the post-modification of materials
via processes such as silylation and atomic layer deposition. All
these methodologies exhibit both advantages and limitations, but all
offer new avenues for the design of catalysts for specific applications.
Because of the high cost of most nanotechnologies and the fact that
the resulting materials may exhibit limited thermal or chemical stability,
they may be best aimed at improving the selective synthesis of high
value-added chemicals, to be incorporated in organic synthesis schemes,
but other applications are being explored as well to address problems
in energy production, for instance, and to design greener chemical
processes. The details of each of these approaches are discussed,
and representative examples are provided. We conclude with some general
remarks on the future of this field.