Bio-nanohybrid materials based on the combination of biomolecules and inorganic supports are interesting by their versatile applications in regenerative medicine, drug delivery, bio-engineering and catalysis. In that context, understanding of organic/inorganic interactions offers an important key to design new and more complex bio-systems with modified interactions. In this thesis, amino acids and synthesised poly-amino acids were immobilised in hydrotalcite-like materials under green, controllable and efficient protocols. Additionally, these nanohybrid materials were used as heterogenized catalysts exhibiting high catalytic activity and selectivity in comparison with their counterpart components. All result data showed that the location and nature of the immobilization had an important role in the final chemical properties; moreover, this novel bio-nanohybrid material exhibited excellent synergistic behaviour which was unique for each material and could be modified according with the reaction requirements. All novel bio-nanohybrid materials were easily synthesised, recovered and, in some cases, reused without appreciable deactivation. / Materiales bio-nanohíbridos compuestos por la combinación de biomoléculas y soportes inorgánicos son interesantes por sus versátiles aplicaciones en medicina regenerativa, transporte de medicamentos, bio-ingeniería y catálisis. En este contexto, el entendimiento de las interacciones orgánico/inorgánicas ofrece importante información para el diseño de nuevos y más complejos bio-sistemas con interacciones modificadas. En esta tesis, amino ácidos y poli-amino ácidos sintéticos fueron inmovilizados en materiales tipo hidrotalcita a través de eficientes y controlables protocolos amigables con el medioambiente. Adicionalmente, estos materiales fueron usados como catalizadores heterogeneizados mostrando alta actividad y selectividad en comparación con sus componentes de partida. En este sentido, la localización y naturaleza de la interacción tuvo un importante rol en las propiedades catalíticas finales; además, estos novedosos materiales mostraron un excelente comportamiento sinérgico el cual fue único y pudo ser modificado de acuerdo a las necesidades en reacción. Todos los materiales bio-nanohíbirdos fueron sintetizados y recuperados con facilidad del medio de reacción y en algunos casos fueron reutilizados sin desactivación apreciable.

<p>Ispitivani su dvostruki slojeviti hidroksidi, LDH i me&scaron;oviti oksidi nastali njihovom<br />razgradnjom, sa različitim sadržajem Mg-Al-Fe i pro&scaron;irenom supstitucijom aluminijuma.<br />Koprecipitacione metode male i velike prezasićenosti odabrane su za sintezu LDH op&scaron;te<br />formule [Mg1_-xM(III)_x(OH)₂](CO₃)_x/2 &sdot; mH₂O, gde M(III) pretstavlja Al i/ili Fe, a x udeo<br />trovalentnih anjona, x = M(III) / [M(II) + M(III)], variran u intervalu 0,15 &lt; x &lt; 0,7.<br />Katalizatori na bazi me&scaron;ovitih oksida sa gvožđem pogodni za upotrebu u redoks<br />reakcijama, formirani su nakon termičke aktivacije - razlaganja LDH. Izvr&scaron;ena je<br />karakterizacija me&scaron;ovitih oksida nastalih iz LDH, kao i netretiranih LDH, ispitivanjem<br />kristalne strukture (XRD), termičke stabilnosti (TG-DTA), teksture (adsorpcija N₂), redoks<br />(H₂ TPR) i kiselo-baznih karakteristika (NH₃ TPD), a utvrđena je i priroda prisutnih vrsta<br />gvožđa (Moessbauer spektroskopija). Pokazano je kako metoda pripreme i obim<br />supstitucije M(III) jona utiču na strukturne, povr&scaron;inske i redoks karakteristike LDH i<br />njihovih me&scaron;ovitih oksida u korelaciji sa katalitičkim svojstvima u odabranim test<br />reakcijama (razgradnja N₂O i redukcija sa NH₃). Utvrđeno je da na katalitičku aktivnost<br />dominantno utiču redoks karakteristike i priroda vrste gvožđa u me&scaron;ovitom oksidu, ali<br />takođe i strukturne karakteristike polaznog LDH, pri čemu je povr&scaron;inska struktura aktivnih<br />centara intervalentnog Fe²⁺-Fe³⁺gvožđa ključna za redoks procese ispitivanih reakcija.<br />Kod svih me&scaron;ovitih oksida dobijenih iz LDH aktivni centri imaju relativno jednake jačine,<br />dok razlike u katalitičkom pona&scaron;anju potiču od razlika u dostupnosti aktivnih centara.<br />Najbolje performanse u katalitičkim reakcijama pokazali su uzorci sa najmanjom<br />stabilno&scaron;ću inicijalnih LDH kod kojih je količina supstituisanih M(III) jona bila blizu<br />granice za inkorporaciju u LDH matricu (x = 0,5), a naročito uzorak sintetisan metodom<br />velike prezasićenosti sa malom količinom dodatne Al(OH)₃ faze.</p> / <p>Layered double hydroxides (LDHs) and derived mixed oxides with different Mg-Al-Fe content and extended aluminum substitution were investigated. High and low supersaturation precipitation methods were used for the synthesis of LDHs with general formula [Mg1_-x M(III)_x (OH)₂](CO₃)_x/2 &sdot; mH₂O where M(III) presents Al and/or Fe and x the content of trivalent ions, x = M(III) / [M(II) + M(III)], varied between 0.15 &lt; x &lt; 0.7. Iron-containing mixed oxides, suitable as catalysts for redox reactions, were formed after thermal activation - decomposition of LDH. Both, LDHs and derived mixed oxides were characterized with respect to crystalline structure (XRD), thermal stability (TG-DTA), textural (N₂ adsorption), redox (H₂ TPR) and acid-base properties (NH₃ TPD) as well as the nature of the iron species (Moessbauer spectroscopy). It was demonstrated how preparation method and the extent of M(III) substitution influence the structure, surface and redox properties of LDHs and derived mixed oxides in correlation to catalytic properties in chosen test reactions (N₂O decomposition and reduction with NH3). The catalytic behavior is mainly determined by the redox properties and the nature of the iron species in mixed oxides, but also by the structural properties of initial LDHs. It was confirmed that surface structure of intervalent Fe²⁺-Fe³⁺ iron active sites is crucial for the redox processes in chosen reactions. The strength of active sites is similar for all mixed oxides derived from LDH, but the differences in catalytic behavior arise from the differences in active sites accessibility. The best catalytic results were obtained when the stability of the initial LDH matrix was lowest e.g. when the amount of substituted M(III) was near the limit for the incorporation into LDH matrix (x = 0.5), especially for the sample synthesized with high superasaturation method containing a small amount of additional Al(OH)₃ phase.</p>