Preparation and characterization of noble metal modified titanium dioxide hollow spheres – new insights concerning the light trapping efficiency

Gyulavári, Tamás; Kovács, Kata; Kovács, Zoltán; Bárdos, Enikő; Kovács, Gábor; Baán, Kornélia; Magyari, Klára; Veréb, Gábor; Pap, Zsolt

doi:10.1016/j.apsusc.2020.147327

Cited by 17 publications

(10 citation statements)

References 54 publications

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“…It should be mentioned that usually, deposition of NMs results in significant activity enhancement under UV irradiation [50,52,[77][78][79][80]. However, there are also some reports showing that NMs could decrease photocatalytic activity [81][82][83][84].…”

Section: Sample Codementioning

confidence: 99%

TiO2/Au/TiO2 Plasmonic Photocatalysts: The Influence of Titania Matrix and Gold Properties

2022

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Plasmonic photocatalysts have gained more and more attention because of possible applications for solar energy conversion, environmental decontamination, and water treatment. However, the activity under visible light is usually very low, and the property-governed activity as well as the mechanisms are not fully understood yet. Accordingly, this study examines four different titania photocatalysts (anatase and rutile with fine and large crystallites) modified with gold by photodeposition. Three kinds of samples were prepared, as follows: (i) gold-modified titania (Au/TiO2), (ii) physically mixed Au/TiO2 samples (Au/TiO2(1) + Au/TiO2(2)), and (iii) Au/(TiO2(1) + Au/TiO2(2)) samples, prepared by subsequent deposition of gold on the mixture of bare and gold-modified titania. In total, twelve samples were prepared and well characterized, including diffuse reflectance spectroscopy (DRS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning transmission electron microscopy (STEM). The photocatalytic activity was examined in three reaction systems: (i) methanol dehydrogenation during gold photodeposition under UV/vis irradiation, (ii) oxidative decomposition of acetic acid (UV/vis), and (iii) oxidation of 2-propanol to acetone under visible light irradiation (λ > 450 nm). It was found that during subsequent deposition, gold is mainly formed on the surface of pre-deposited Au nanoparticles (NPs), localized on fine titania NPs, through the electrostatic attractions (negatively charged gold resulting from photogenerated electrons’ accumulation). This gold aggregation, though detrimental for UV activity (many “naked” large titania with low activity), is highly beneficial for vis activity because of efficient light harvesting and increased interface between gold and titania (gold deposits surrounded by fine titania NPs). Moreover, it was found that rutile is more active than anatase for plasmonic photocatalysis, probably due to easier electron transfer from gold via titania to adsorbed oxygen (more negative conduction band), which might hinder the back reaction (electron transfer: Au→TiO2→Au).

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Section: Sample Codementioning

confidence: 99%

TiO2/Au/TiO2 Plasmonic Photocatalysts: The Influence of Titania Matrix and Gold Properties

2022

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“…The hydrothermal synthesis of CS templates was carried out according to our recent publication [28] as follows. In a PTFE-lined autoclave, a 0.15 M water-based solution of sucrose was prepared (V fill /V total = 29%) and the pH was set to 12 using a 2 M NaOH solution.…”

Section: Synthesis Of Carbon Sphere Templatesmentioning

confidence: 99%

“…In the case of glucose-derived CSs used in the literature using ZnAc 2 and ZnCl 2 the impregnation of the surface occurred relatively successful [31][32][33]. The used purification method for the CSs has already proven in our previous research that efficiently removes the by-products of the carbonization process [28]. This results in less functional groups on the surface which could participate in polar-polar interactions.…”

Section: Morphological Characterization Of Zno Hssmentioning

confidence: 99%

“…In our previous publication, a low-cost method was applied to prepare similar carbon spheres from sucrose, which were used as a template to synthesize hollow TiO 2 spheres. This way, the photocatalytic efficiency of TiO 2 spheres could also be improved [28]. This made the method more versatile and further reduced cost of materials.…”

Section: Introductionmentioning

confidence: 98%

“…Higher economic feasibility can be achieved because the degradation efficiency to mass ratio is increased [25][26][27]. v. These materials can possess enhanced light harvesting capabilities through the constructive interference of light waves in the cavity [28].…”

Section: Introductionmentioning

confidence: 99%

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Noble Metal Modified (002)-Oriented ZnO Hollow Spheres for the Degradation of a Broad Range of Pollutants

et al. 2021

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Adsorption‐Induced In‐Situ Construction of TiO₂ Hollow Sphere/UiO‐66‐NH₂ Heterostructures with Boosted Photocatalytic Activity toward Cr(VI) Reduction

et al. 2023

ChemNanoMat

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Water contamination caused by highly toxic Cr(VI) should be resolved imminently with a more efficient photocatalytic approach. The interaction between photocatalyst heterostructure is critical for charge separation which largely affects the photocatalytic efficiency. Herein, TiO2 hollow sphere/UiO‐66‐NH2 (TiO2/UiO‐66‐NH2) heterostructures were successfully synthesized by an adsorption‐induced in‐situ solvothermal growth strategy. The UiO‐66‐NH2 particles were well dispersed on TiO2 hollow spheres by solvothermal treatment of Zr4+ adsorbed TiO2 hollow spheres with NH2‐BDC ligand. The photocatalytic activities of TiO2/UiO‐66‐NH2 heterostructures were investigated by reduction of Cr(VI) with visible light irradiation. With the introduction of UiO‐66‐NH2, the reduction efficiency toward Cr(VI) by TiO2/UiO‐66‐NH2 heterostructures reached 89% after 180 min of irradiation, which is much higher than those of TiO2 hollow spheres (10%) and UiO‐66‐NH2 crystals (29%). Moreover, the TiO2/UiO‐66‐NH2 heterostructures display good regeneration ability and can still maintain 70% of Cr(VI) removal ability after four cycles. The integration of TiO2 and UiO‐66‐NH2 could construct a type‐II heterojunction to broaden the absorption range of light and suppress the recombination of photoproduced electrons and holes. As a result, such unique composite structure significantly enhance the photocatalytic performance towards Cr(VI) reduction. This work not only inspires a new approach for in‐situ solvothermal synthesis of semiconductor@MOFs composites, but provides a novel photocatalyst for highly efficient removal of Cr(VI) from wastewater.

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Preparation and characterization of noble metal modified titanium dioxide hollow spheres – new insights concerning the light trapping efficiency

Cited by 17 publications

References 54 publications

TiO2/Au/TiO2 Plasmonic Photocatalysts: The Influence of Titania Matrix and Gold Properties

TiO2/Au/TiO2 Plasmonic Photocatalysts: The Influence of Titania Matrix and Gold Properties

Noble Metal Modified (002)-Oriented ZnO Hollow Spheres for the Degradation of a Broad Range of Pollutants

Adsorption‐Induced In‐Situ Construction of TiO₂ Hollow Sphere/UiO‐66‐NH₂ Heterostructures with Boosted Photocatalytic Activity toward Cr(VI) Reduction

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Preparation and characterization of noble metal modified titanium dioxide hollow spheres – new insights concerning the light trapping efficiency

Cited by 17 publications

References 54 publications

TiO2/Au/TiO2 Plasmonic Photocatalysts: The Influence of Titania Matrix and Gold Properties

TiO2/Au/TiO2 Plasmonic Photocatalysts: The Influence of Titania Matrix and Gold Properties

Noble Metal Modified (002)-Oriented ZnO Hollow Spheres for the Degradation of a Broad Range of Pollutants

Adsorption‐Induced In‐Situ Construction of TiO2 Hollow Sphere/UiO‐66‐NH2 Heterostructures with Boosted Photocatalytic Activity toward Cr(VI) Reduction

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Product

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Adsorption‐Induced In‐Situ Construction of TiO₂ Hollow Sphere/UiO‐66‐NH₂ Heterostructures with Boosted Photocatalytic Activity toward Cr(VI) Reduction