31. FOTOELEKTROKEMIČNI RAZKROJ BARVILA RODAMIN B V ODPADNIH VODAH Z UPORABO NANOSOV S FLUOROM DOPIRANEGA KOSITROVEGA OKSIDAMatjaž Reya, 2019, diplomsko delo Opis: V diplomskem delu smo z metodo fotoelektrokatalitičnega procesa opazovali razgradnjo barvila rodamin B v vodi. Izmerili smo čas, ki je bil potreben, da se je barvilo razgradilo in se je voda razbarvala. Vzorce smo analizirali s pomočjo UV-Vis spektroskopije. Raziskavo smo izvajali v foto-elektrokemijski celici, pri čemer smo uporabili anodo, katodo in referenčno elektrodo. Za anodo smo uporabili steklo z nanosom s fluorom dopiranim kositrovim oksidom (ang. fluorine doped tin oxide - FTO). Enako steklo smo izbrali za katodo, premazali smo jo s platino (Pt), za referenčno elektrodo pa smo uporabili srebro-srebrovo kloridno elektrodo (Ag|AgCl). Eksperiment je bil sestavljen iz treh obravnav z namenom primerjanja podatkov v različnih pogojih. Uporabili smo svetila treh valovnih dolžin 365 nm, 405 nm, in Vis svetlobo (> 400 nm). Potek reakcije smo preverili z uporabo 0,01 M žveplove kisline (H2SO4) in 0,001 M natrijevega hidroksida (NaOH). Ugotovili smo, da se je barvilo rodamin B koncentracije 1 × 10-5 mol/L, razgradilo samo v kislem mediju, z uporabo svetila valovne dolžine = 405 nm. Razgradnja je v tem primeru potekala od 30 do 80 min. Na čas, ki je bil potreben za razgradnjo barvila, je bistveno vplivala aktivacija filma FTO. Eksperiment smo izvedli tudi brez svetila, v popolni temi, ta je, glede na poskuse z svetilom, potekel bistveno počasneje ali sploh ni potekel. Ključne besede: Fotoelektrokataliza, rodamin B, FTO, razgradnja barvila, čiščenje vode Objavljeno v RUNG: 21.10.2019; Ogledov: 4788; Prenosov: 129 Celotno besedilo (1,73 MB) |
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36. Synthesis of molybdenum carbide thin films for production of hydrogen via electrochemical water splitting : M. Sc. thesisCesur Altinkaya, 2018, magistrsko delo Ključne besede: molybdenum, platinum, molybdenum carbide thin films, hydrogen evolution reaction, water splitting, electrolysis, electrochemistry, pyrolysis, thin films Objavljeno v RUNG: 30.08.2018; Ogledov: 4819; Prenosov: 0 Gradivo ima več datotek! Več... |
37. Tungsten carbide electrocatalysts prepared from metallic tungsten nanoparticles for efficient hydrogen evolutionSaim Emin, Cesur Altinkaya, Ali Semerci, Hasan Okuyucu, Abdullah Yildiz, Plamen Stefanov, 2018, izvirni znanstveni članek Ključne besede: Tungsten carbide, Colloid, Hydrogen evolution, Overpotential, Electrocatalyst Objavljeno v RUNG: 23.05.2018; Ogledov: 4618; Prenosov: 0 Gradivo ima več datotek! Več... |
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39. Photoelectrochemical Water Splitting Studies with nanostructured n and p-type semiconductor electrodesSaim Emin, Matjaž Valant, 2017, objavljeni povzetek znanstvenega prispevka na konferenci (vabljeno predavanje) Opis: Photoelectrochemical water splitting has been demonstrated as a promising way to efficiently split water. Currently, solar-to-hydrogen conversion efficiency using state-of-the-art material combinations in PEC system is in the order of 7%. Fabrication of nanostructured materials with unique morphologies and compositions is an important factor to fully utilize the possibilities in this field. We will present different strategies for the preparation of nanostructured metal oxide thin films by using electrodeposition and wet-chemistry techniques. Focus will be given on the preparation of ZnO and CuO thin films where intermediate phases like Zn(OH)8Cl2.H2O and CuX (X=Br, Cl) were electrodeposited. Wet-chemistry synthesis techniques will be also explored for the preparation of nanostructured WO3 and a-Fe2O3 thin films. Especially, the hot-pyrolysis technique for the preparation of colloidal W and Fe/Fe-oxide nanoparticles will be shown. Spin-coating of W and Fe/Fe-oxide NPs onto optically conductive substrates and subsequent heat treatment of the obtained films was found to be a convenient way for the preparation of nanostructured WO3 and a-Fe2O3 thin films. Ključne besede: photoelectrochemical water splitting, colloidal nanoparticles, semiconductor Objavljeno v RUNG: 24.10.2017; Ogledov: 4378; Prenosov: 0 Gradivo ima več datotek! Več... |
40. Metal oxide and metal carbides thin films for photo/electrochemical water splitting studiesSaim Emin, 2017, objavljeni povzetek znanstvenega prispevka na konferenci Opis: We used wet-chemistry techniques to prepare colloidal tungsten (W) nanoparticles (NPs). The synthesis of W NPs was conducted using the so called hot-matrix method in 1-octadecene [1]. The sizes of obtained W NPs are in the order of 2 - 5 nm. These W NPs are coated with hydrophobic molecules which allow their dispersion in organic solvents like choloroform (CHCl3). It was found that the colloidal stability of the dispersions is exceptionally high exceeding several years. The stability of W NPs which prevents coagulation allows the preparation of thin films with uniform thicknesses by spin-coating, inkjet-printing and spray coating.
We have prepared both tungsten trioxide (WO3) and tungsten carbide (W2C, WC) thin films. The preparation of WO3 thin films was achieved by spin-coating of W NPs on fluorine doped tin oxide (FTO) glass substrates and following thermal treatment in air at 500°C. The preparation of W2C and WC were done after spin-coating of W NPs on graphite substrate and following heat treatment under Ar atmosphere at 1000 and 1450°C.
The obtained WO3 and W2C (e.g WC) films were used both in photo/electrochemical water splitting studies. In conclusion, we have developed a procedure for the synthesis of W NPs which can be used for the preparation of different class of materials for water splitting studies. Ključne besede: metal oxides, metal carbides, tungsten nanoparticles Objavljeno v RUNG: 09.10.2017; Ogledov: 5188; Prenosov: 0 Gradivo ima več datotek! Več... |