Környezetvédelmileg ártalmas anyagok csökkentése arany és ezüst katalizátorral: a szerkezetfüggés modellezése = Gold and silver catalysts for abatement of environmentally harmful materials: modelling the structure dependency

A gepkocsik kipufogo gazaiban nagy mennyisegű NOx, CO es szenhidrogen-szarmazek talalhato, amelyek artalmasak az emberi szervezetre. Ezek a komponensek drasztikusan csokkenthetők a haromutas katalizator alkalmazasaval. A napjainkban alkalmazott haromutas katalizatorokban Pt, Pd es Rh talalhato cirkonium-oxid stabilizalt cerium-oxid, cirkonium-oxid es α-aluminium-oxid hordozon. A jelen munka celja volt Au es Ag alapu katalizator csalad fejlesztese a draga Pt es Rh helyettesitesere. Au-Ag ketfemes es az egyfemes Au es Ag mintakat SiO2, TiO2 es CeO2 hordozon allitottunk elő szol adszorpcios modszerrel, hogy vizsgaljuk a ket fem egymasra hatasat az otvozet fazisban, es a hordozo hatast. Au/ es Ag/redukalhato femoxid hatarfeluletek hatasat kulonboző jol definialt szerkezetű modell katalizatorokon vizsgaltuk. Ezert Au es Ag nanoreszecskeket es retegeket parologtattunk kontrolalt korulmenyek kozott a nativ SiO2-vel boritott Si(100) feluletekre kulonboző modszerekkel (PLD, MBE, magnetron porlasztas). Redukalhato oxid (pl. TiO2 FeOx es CeO2) Au-val es Ag-vel alkotott hatarfeluletet tobbfele szerkezettel hoztuk letre, kulonboző sorrendben epitve egymasra a reszecskes vagy a vekonyreteg szerkezetű komponenseket. A mintak jellemzeset kulonboző modszerekkel vegeztuk (XPS, AFM, TEM, XRD, SIMS), valamint vizsgaltuk őket CO oxidacioban es NOx redukciojaban, valamint kiegesziteskent glukoz szelektiv oxidaciojaban. | Automotive exhaust gas contains high concentrations of NOx, CO, and hydrocarbons, which are harmful to human health. These components can be reduced drastically by the use of a three-way catalyst. All commercial three way catalysts in use at present are based on Pt, Pd, and Rh on a support comprised of zirconia-stabilized ceria, zirconia and α-alumina. The present project was aimed at developing a novel family of catalysts, based on Au and Ag, the most promising alternative candidates, to replace the more expensive Pt and Rh. We produced SiO2, TiO2 and CeO2 supported bimetallic Au-Ag and monometallic Au and Ag particles using sol preparation and adsorption method to clarify the cooperation of the two metals in the alloyed phase, and the support effect. The effect of the Au/, Ag/reducible metal oxide interface was studied with model catalysts of well defined various structures produced by different techniques. For this purpose Au and Ag nanoparticles and layers were evaporated in controlled ways onto Si(100) wafers using different new techniques (PLD, MBE, magnetron sputtering). Interface of gold and different oxides like TiO2, FeOx and CeO2 were created in different morphology fabricating of the layers or particles of the two components and changing of the order of the deposition. The samples were characterized by different techniques (XPS, AFM, TEM, XRD, SIMS), and studied in CO oxidation and NOx reduction as well as additionally in glucose selective oxidation.