1. Photocatalytic CO2 reduction over mesoporous TiO2 photocatalystsMartin Reli, Peter Nadrah, Miroslava Filip Edelmannová, Rudolf Ricka, Andrijana Sever Škapin, Urška Lavrenčič Štangar, Kamila Kočí, 2024, izvirni znanstveni članek Povzetek: In this study, we investigated different synthesis methods (template-free and template-based) using copolymers of poly(ethylene oxide) and poly(propylene oxide) to enhance the CO2 reduction activity of mesoporous TiO2. Our main goal was to identify key factors affecting photocatalyst efficiency and selectivity. We compared the newly synthesized TiO2 photocatalysts with the commercial photocatalyst P25. Among the materials studied, TiO2-P123 in its pure anatase form demonstrated the highest photoreduction efficiency and CO2 selectivity. In contrast, TiO2-EG, TiO2-F127, and P25, which contained both rutile and anatase phases, exhibited decreased photoactivity due to the formation of a type II heterojunction between the phases and higher oxygen adsorption on rutile's surface. Additionally, we observed that the choice of chemicals for photocatalyst preparation significantly influenced the specific surface area. TiO2-P123, the most active photocatalyst, had the highest specific surface area, providing more reactive sites for improved light absorption efficiency and prolonged electron-hole pair lifetimes, resulting in enhanced photocatalytic activity. We also calculated apparent quantum yields to support our findings.
Ključne besede: CO2 reduction, TiO2, photocatalysis, mesoporous material, Sol-gel method
Objavljeno v DiRROS: 14.11.2023; Ogledov: 371; Prenosov: 39
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2. Photocatalytic reduction of carbon dioxide to methanol : carbonaceous materials, kinetics, industrial feasibility, and future directionsGanji Parameswaram, Ramesh Kumar Chowdari, Blaž Likozar, 2023, pregledni znanstveni članek Ključne besede: alcohols, catalysts, oxides, photocatalysis, two dimensional materials
Objavljeno v DiRROS: 23.06.2023; Ogledov: 328; Prenosov: 160
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3. Photo, thermal and photothermal activity of ▫$TiO_2$▫ supported Pt catalysts for plasmon-driven environmental applicationsGregor Žerjav, Zafer Say, Janez Zavašnik, Matjaž Finšgar, Christoph Langhammer, Albin Pintar, 2023, izvirni znanstveni članek Povzetek: TiO2+Pt plasmonic solids with 1 wt% Pt and different TiO2 supports (anatase nanoparticles (TNP), polycrystalline nanorods (a-TNR) and single-crystal anatase nanorods (TNR)) were synthesized using the wet impregnation technique and tested as photo, thermal and photothermal catalysts in gas-solid and gas-liquid-solid reactions. Due to the different charges of the TiO2 support surfaces, Pt particles with different sizes, crystallinities and degrees of interaction with the TiO2 supports were formed during the synthesis. The heights of the Schottky barrier (SBH) were 0.38 eV for the a-TNR+Pt, 0.41 eV for the TNP+Pt, and 0.50 eV for the TNR+Pt samples, respectively. The low visible-light-triggered photocatalytic activity of the TNR+Pt catalyst toward the oxidation of water-dissolved bisphenol A (BPA) is attributed to its high SBH and active site deactivation due to the adsorption of BPA and/or BPA oxidation products. The highest photothermal catalytic H2-assisted NO2 reduction rate was expressed by the TNR+Pt catalyst. This can be ascribed to the presence of a narrow particle size distribution of small Pt particles, the absence of the Pt catalysed reduction of the TNR support at higher temperatures, and the lower rate of re-injection of “hot electrons” from the TNR support to the Pt particles.
Ključne besede: heterogeneous photocatalysis, titanium dioxide, plasmonic noble metal, platinum particles, visible light illumination, Schottky barrier height, bisphenol A, wastewater treatment, NOx abatement, air cleaning, microreactor, thermal catalysis, photothermal catalysis
Objavljeno v DiRROS: 23.06.2023; Ogledov: 379; Prenosov: 196
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4. Metal and non-metal modified titania : the effect of phase composition and surface area on photocatalytic activityBoštjan Žener, Lev Matoh, Martin Reli, Andrijana Sever Škapin, Romana Cerc Korošec, 2022, izvirni znanstveni članek Povzetek: The application of TiO 2 photocatalysis in various environmental fields has been extensively studied in the last decades due to its ability to induce the degradation of adsorbed organic pollutants. In the present work, TiO 2 powders doped and co-doped with sulfur and nitrogen and modified with platinum were prepared by particulate sol-gel synthesis. PXRD measurements revealed that the replacement of HCl with H 2SO4 during synthesis reduced the size of the crystallites from ~ 30 nm to ~20 nm, increasing the surface area from ~44 m2/g to ~80 m2/g. This is consistent with the photocatalytic activity of the samples and the measured photocurrent behavior of the photocatalysts. The results showed that the prop- erties of the powders (i.e., surface area, crystallite size, photocurrent behavior) depend strongly not only on the type but also on the amount of acid and dopants used in the synthesis. Doping, co-doping and modification of TiO 2 samples with nitrogen, sulfur and platinum increased their photocatalytic activity up to 6 times.
Ključne besede: titanium dioxide, powders, doping, photocatalysis, photocurrent, SEM
Objavljeno v DiRROS: 04.05.2023; Ogledov: 340; Prenosov: 142
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5. Synthesis and characterization of plasmonic ▫$Au/TiO_2$▫ nanorod solids for heterogeneous photocatalysisŠpela Slapničar, Gregor Žerjav, Janez Zavašnik, Matjaž Finšgar, Albin Pintar, 2023, izvirni znanstveni članek Povzetek: Plasmonic Au (1 wt%) catalysts deposited on hydrothermally synthesized TiO2 nanorods (TNR) were investigated in this study. Based on the duration of mixing of the Au precursor/TNR suspension during the wet impregnation synthesis and parameters of the end calcination, Au/TiO2 catalysts with different sizes of Au nanoparticles (Au NPs) were obtained. The prepared solids were thoroughly characterized by several instrumental techniques to investigate property-activity relationships. Regardless of the size of Au particles on the catalyst surface, an absorption peak at 550 nm occurred in all UV-Vis diffuse reflectance spectra of the investigated Au/TiO2 catalysts, which is characteristic of the localized surface plasmon resonance effect exerted by metallic Au NPs. By measuring the formation of reactive oxygen species under visible-light illumination using various scavengers, the production of superoxide anion radicals (O2•single bond) and hydroxyl radicals were identified, however, the former were found to represent the main reactive oxygen species that govern the oxidation of aqueous bisphenol A (BPA) employed as a model organic pollutant. The activity of Au/TiO2 catalysts for the generation of O2•single bond radicals (and BPA oxidation) increases by increasing the Schottky barrier height, which is due to the slow reduction of water-dissolved O2 on the catalyst surface.
Ključne besede: heterogeneous photocatalysis, titanate nanorods, gold nanoparticles, wet impregnation, localized surface plasmon resonance effect
Objavljeno v DiRROS: 26.04.2023; Ogledov: 516; Prenosov: 231
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6. Influence of the calcination duration of ▫$g-C_3N_4/TiO_2$▫ veggie-toast-like photocatalyst on the visible-light triggered photocatalytic oxidation of bisphenol AMatevž Roškarič, Gregor Žerjav, Matjaž Finšgar, Janez Zavašnik, Albin Pintar, 2023, izvirni znanstveni članek Povzetek: Two commercially available TiO2 (hexagonal-like and spherical-like particles) were used to investigate the effect of g-C3N4 “melting” on the photocatalytic properties of g-C3N4/TiO2 composites. Improvement in the contact between the components was observed when they were thermally treated at 350 °C for an extended period of time (between 2 and 72 h) due to the partial melting and phase fusion of g-C3N4. Consequently, the enhanced contact between the phases allows easier injection of photogenerated electrons from the conduction band of g-C3N4 into TiO2, improving charge carrier separation. The prepared composites were tested for bisphenol A degradation under visible-light illumination, which showed that the components that had been calcined for 24 h performed better due to the improved charge carrier separation. Superoxide anionic radicals and photogenerated holes were identified as active species in the photooxidation experiments conducted under visible-light illumination.
Ključne besede: titanium dioxide, photocatalyst, calcination time, photocatalysis under visible-light illumination, water remediation, bisphenol A
Objavljeno v DiRROS: 17.03.2023; Ogledov: 562; Prenosov: 274
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