Objetivos e Atividades
It is well known that of homogeneous catalysts have remarkable properties, such as high activity, and enantioselectivity, but heterogeneous systems have advantages like longer catalyst lifetimes, easier separation and possible recycling. The aim of this project was to combine the best of those "two worlds", by anchoring (soluble) metal complexes on porous (carbon, solid) materials.
Complexes of Au, but also of other metals, such as Fe and V complexes were heterogenized on carbon supports (activated carbon, carbon xerogels, carbon nanotubes, micro- and nano-diamonds, etc). Gold nanoparticles deposited on those supports (and also on metal oxides) were used for comparison. Catalysis were used for the transformation of alkanes and alcohols into high added value products.
In addition, gold catalysts and noble metal free mixed oxides were also used for other reactions, such as CO and volatile compounds oxidation, photocatalysis, among others.
Resultados Esperados/Atingidos
It was shown that heterogenized gold complexes could have superior activities than the homogenous counterparts, and also the possibility of recycling. The use of such materials also allowed reactions to be made in milder and "greener" conditions, like the absence of acid. In some cases, activities of heterogenized gold complexes were superior to those obtained with gold nanoparticles on the same supports, like in alkane oxidation. Also, gold showed activities superior to other metals in several reactions, like the oxidation of alcohols. Catalysts without noble metals also shown very interesting and promising results.
This project led to the publication of more than 60 papers, 6 of them were journal covers, 2 being considered as "highly cited" (by the Web of Knowledge), 5 chapters in books, more than 80 conference presentations and 1 national patent, with international request already granted in Europe (pending for USA, China and Japan).
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