41. Solvothermal synthesis of iron phosphides and their application for efficient electrocatalytic hydrogen evolutionTakwa Chouki, Manel Machreki, Saim Emin, 2020, original scientific article Abstract: Abstract
In this paper, we present a solvothermal synthesis of iron phosphide electrocatalysts using a triphenylphosphine (TPP) precursor. The synthetic protocol generates Fe2P phase at 300 °C and FeP phase at 350 °C. To enhance the catalytic activities of obtained iron phosphide particles heat-treatments were carried out at elevated temperatures. Annealing at 500 °C under reductive atmosphere induced structural changes in the samples: (i) Fe2P provided a pure Fe3P phase (Fe3P−500 °C) and (ii) FeP transformed into a mixture of iron phosphide phases (Fe2P/FeP−500 °C). Pure Fe2P films was prepared under argon atmosphere at 450 °C (Fe2P−450 °C). The electrocatalytic activities of heat-treated Fe2P−450 °C, Fe3P−500 °C, and Fe2P/FeP−500 °C catalysts were studied for hydrogen evolution reaction (HER) in 0.5 M H2SO4. The HER activities of the iron phosphide catalyst were found to be phase dependent. The lowest electrode potential of 110 mV vs. a reversible hydrogen electrode (RHE) at 10 mA cm−2 was achieved with Fe2P/FeP−500 °C catalyst.
Keywords: Solvothermal synthesis, Iron phosphide, Electrocatalyst, Hydrogen evolution, Overpotential
Published in RUNG: 20.07.2020; Views: 4156; Downloads: 0
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42. Improved photocatalytic activity of anatase-rutile nanocomposites induced by low-temperature sol-gel Sn-modification of TiO2Ksenija Maver, Iztok Arčon, Urška Lavrenčič Štangar, Mattia Fanetti, Saim Emin, Matjaž Valant, 2020, original scientific article Abstract: The Sn-modified TiO2 photocatalysts are prepared by low-temperature sol-gel processing based on organic titanium
and tin precursors with varied Sn concentrations (from 0.1–20 mol .%). The role of Sn dopant as the
promotor of the formation of TiO2 rutile crystalline phase is explained and the optimal Sn concentration for
preparation of efficient Sn-modified titania photocatalyst is determined. Up to 40 % increase in photocatalytic
activity is achieved in Sn-modified TiO2 photocatalytic thin films dried at 150 °C with low Sn concentrations in
the range from 0.1 to 1 mol .%. At low Sn concentrations optimal ratio between anatase and rutile (nano)crystals
is obtained, which facilitates charge separation at the TiO2 photocatalyst’s surface. When the concentration of Sn
increases above 5 mol.% or when the films are calcined at 500 °C, the relative amount of rutile phase with
inferior photocatalytic activity, increases and the nanocrystals of titania grow, leading to fewer active sites per
unit mass and the reduction of activity in comparison to unmodified TiO2.
Keywords: Anatase-rutile
Sn-modified TiO2
XAS analysis
Photocatalytic activity
Published in RUNG: 10.02.2020; Views: 3931; Downloads: 0
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43. FOTOELEKTROKEMIČNI RAZKROJ BARVILA RODAMIN B V ODPADNIH VODAH Z UPORABO NANOSOV S FLUOROM DOPIRANEGA KOSITROVEGA OKSIDAMatjaž Reya, 2019, undergraduate thesis Abstract: 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.
Keywords: Fotoelektrokataliza, rodamin B, FTO, razgradnja barvila, čiščenje vode
Published in RUNG: 21.10.2019; Views: 6272; Downloads: 142
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48. Synthesis of molybdenum carbide thin films for production of hydrogen via electrochemical water splitting : M. Sc. thesisCesur Altinkaya, 2018, master's thesis Keywords: molybdenum, platinum, molybdenum carbide thin films, hydrogen evolution reaction, water splitting, electrolysis, electrochemistry, pyrolysis, thin films
Published in RUNG: 30.08.2018; Views: 6072; Downloads: 0
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49. Tungsten carbide electrocatalysts prepared from metallic tungsten nanoparticles for efficient hydrogen evolutionSaim Emin, Cesur Altinkaya, Ali Semerci, Hasan Okuyucu, Abdullah Yildiz, Plamen Stefanov, 2018, original scientific article Keywords: Tungsten carbide, Colloid, Hydrogen evolution, Overpotential, Electrocatalyst
Published in RUNG: 23.05.2018; Views: 5685; Downloads: 0
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