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1.
Okolju prijazna sinteza metanola s hidrogeniranjem ogljikovega dioksida preko trikomponentnih katalizatorjev
Teja Cankar, 2017, undergraduate thesis

Abstract: Zaradi naraščanja koncentracije CO2 v ozračju in njenega negativnega vpliva na okolje, se išče načine, s katerimi bi to koncentracijo zmanjšali. Ena izmed možnosti je direktna hidrogenacija atmosferskega CO2 do metanola, s čimer bi CO2 uporabili kot surovino, hkrati pa pridobili metanol, ki je uporabna kemikalija. Ta proces zahteva uporabo učinkovitega in stabilnega katalizatorja ter optimalne reakcijske pogoje. V tem raziskovalnem delu smo s katalitičnimi testi proučevali vpliv reakcijskih pogojev, različnih komponent katalizatorja in sinteznih metod na učinkovitost katalizatorjev za sintezo metanola. Kot optimalna temperatura in tlak sta se izkazala območja od 220 do 240 °C in od 40 do 50 barov, kjer je reakcija dovolj hitra, hkrati pa še ni bistveno termodinamsko zavrta, in pride do zadostne količine sintetiziranega metanola. Kot najbolj učinkovito molsko razmerje plinov se je izkazalo H2 : CO2 = 3 : 1 in kot najbolj učinkovita plinska urna prostorska hitrost 6000 h-1. To sta pogoja, kjer je količina sintetiziranega metanola zadosti velika ob sprejemljivi porabi reaktantov. Kot najbolj učinkovit katalizator se je izkazal komercialno uporabljen HiFUEL®, dobre lastnosti pa sta pokazala tudi CuO/MgO/Al2O3 in CuO/ZnO/CeO2. CuO/MgO/Al2O3 katalizator je dobro aktiven v širšem temperaturnem območju (220–260 °C), njegova aktivnost je okoli 0,6 molCH3OH•l-1•h-1. Prednost CuO/ZnO/CeO2 katalizatorja pa je izredno visoka selektivnost, in sicer pri 220 °C približno 65 %.
Found in: osebi
Keywords: hidrogenacija CO2, sinteza metanola, učinkovitost katalizatorjev, reakcijski pogoji, različna sestava katalizatorjev
Published: 17.11.2017; Views: 1737; Downloads: 103
.pdf Fulltext (5,84 MB)

2.
Synthesis of a Cu/ZnO Nanocomposite by Electroless Plating for the Catalytic Conversion of CO2 to Methanol
Maja Pori, Iztok Arčon, Marjan Marinšek, Goran Dražić, Blaž Likozar, Zorica Crnjak Orel, Damjan Lašič Jurković, 2019, original scientific article

Abstract: The process of methanol synthesis based on the hydrogenation of CO2 was investigated over binary Cu/ZnO catalyst materials, prepared by applying a novel electroless plating fabrication method. The activity of the produced catalytic samples was determined at temperature range between 200 and 300 °C and the feedstock conversion data were supplemented with a detailed microstructure analysis using high-resolution transmission electron microscopy (HRTEM), X-ray powder diffraction (XRD) and Cu and Zn K-edge, X-ray absorption near-edge structure (XANES) measurements and extended X-ray absorption fine-structure (EXAFS) measurements. It was confirmed that the disorder in the Cu crystallites created unique geometrical situations, which acted as the additional reactive centres for the adsorption of the reactant molecule species. Copper and zinc structural synergy (spill-over) was also demonstrated as being crucial for the carbon dioxide’s activation. EXAFS and XANES results provide strong evidence for surface alloying between copper and zinc and thus the present results demonstrate new approach applicable for explaining metal–support interactions.
Found in: osebi
Keywords: EXAFS, CuZn alloy, Spillover mechanism, CO2 valorization, Electroless deposition method, Heterogeneous catalysis
Published: 12.04.2019; Views: 421; Downloads: 0
.pdf Fulltext (1,92 MB)

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