scholarly journals Plasmonic Titania Photocatalysts Active under UV and Visible-Light Irradiation: Influence of Gold Amount, Size, and Shape

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Ewa Kowalska ◽  
Sven Rau ◽  
Bunsho Ohtani
Keyword(s):  
Acetic Acid ◽  
Visible Light ◽  
Surface Area ◽  
Visible Light Irradiation ◽  
Light Irradiation ◽  
Methanol Dehydrogenation ◽  
Size And Shape ◽  
Anatase Titania ◽  
Rutile Titania ◽  
Gold Nps

Plasmonic titania photocatalysts were prepared by titania modification with gold by photodeposition. It was found that for smaller amount of deposited gold (≤0.1 wt%), anatase presence and large surface area were beneficial for efficient hydrogen evolution during methanol dehydrogenation. After testing twelve amounts of deposited gold on large rutile titania, the existence of three optima for 0.5, 2 and >6 wt% of gold was found during acetic acid degradation. Under visible light irradiation, in the case of small gold NPs deposited on fine anatase titania, the dependence of photoactivity on gold amount was parabolic, and large gold amount (2 wt%), observable as an intensively coloured powder, caused photoactivity decrease. While for large gold NPs deposited on large rutile titania, the dependence represented cascade increase, due to change of size and shape of deposited gold with its amount increase. It has been thought that spherical/hemispherical shape of gold NPs, in comparison with rod-like ones, is beneficial for higher level of photoactivity under visible light irradiation. For all tested systems and regardless of deposited amount of gold, each rutile Au/TiO2photocatalyst of large gold and titania NPs exhibited much higher photoactivity than anatase Au/TiO2of small gold and titania NPs.

scholarly journals Gemini surfactant abetted synthesis of mesoporous Mn/Mg bimetal doped TiO2 nanomaterial: Characterization and photocatalytic activity studies under visible light irradiation

2020 ◽  
Author(s):  
Sankara Rao Miditana ◽  
Siva Rao Tirukkovalluri ◽  
Imandi Manga Raju ◽  
Shaik Abdul Alim ◽  
Genji Jaishree ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Surface Area ◽  
Visible Light Irradiation ◽  
Gemini Surfactant ◽  
Light Irradiation ◽  
Oh Radicals ◽  
X Ray ◽  
Ft Ir

Abstract The present work mainly aimed to synthesize different weight percentages (0.25-1.00 wt%) of Manganese (Mn2+) and Magnesium (Mg2+) bimetal ions doped TiO2 nanomaterial assisted with different weight percentages (5-15 wt%) of Gemini Surfactant (GS) using sol-gel method. The bimetal doped and undoped TiO2 photocatalysts were characterized by X-ray Diffraction, Scanning Electron Microscopy, Energy Dispersive X-ray Spectroscopy, Fourier Transform Infrared Spectroscopy (FT-IR), UV-Visible Diffused Reflectance Spectroscopy, Transmission Electron Microscopy, Brunauer-Emmett-Teller surface area analyzer, and Photoluminescence Spectroscopy. Characterization results evinced that Mn2+/Mg2+ bimetal ions doping and encapsulation of GS on TiO2 nanoparticles promote the formation of mesoporous multi-particle anatase TiO2 nanocatalysts with a narrowed band gap, less particle size, and high surface area. The surface elemental composition of the 0.25 wt% Mn2+& 1.00 wt% Mg2+ bimetal doped TiO2 in presence of 10 wt% of Gemini surfactant (after calcination) revealed the presence of both the metal dopants Mn2+ and Mg2+ along with the Ti and O and their chemical interactions were further confirmed by FT-IR results. The photocatalytic activity of these catalysts was assessed by the degradation of Methyl Red (MR) using visible light irradiation. To understand the effect of different reaction parameters on the photocatalytic activity of the nanocatalysts such as the dopant concentration, GS concentration, catalyst dosage, solution pH, and initial dye concentrations were investigated and optimized to achieve the best performance. The photoluminescence results conclude that OH radicals are the crucial reactive species responsible for oxidative photocatalytic degradation of MR.

Development of Plasmonic Photocatalysts for Environmental Application

2014 ◽  
Vol 93 ◽  
pp. 174-183 ◽  
Author(s):  
Ewa Kowalska ◽  
Zhi Shun Wei ◽  
Baris Karabiyik ◽  
Marcin Janczarek ◽  
Maya Endo ◽  
...  
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Noble Metals ◽  
Light Irradiation ◽  
Environmental Application ◽  
Shape Distribution ◽  
Photocatalytic Activities ◽  
Catalytically Active ◽  
Gold Nps ◽  
High Level

Regarding catalytic and plasmonic properties of gold nanoparticles (NPs), the novel area of research on photocatalytic gold properties has been recently started. In contrast with catalytically active gold NPs, where nanosized gold is recommended, our results showed that polydispersity of deposited gold NPs on semiconducting support was beneficial for photocatalytic activity under visible light irradiation. It is thought that wide size/shape distribution of gold NPs, and thus the ability of absorption of light in a wide wavelengths range is responsible for the high level of photoactivity. Though desirable absorption properties of plasmonic photocatalysts can be easily obtained by preparation of nanoparticles of different sizes and shapes, their photocatalytic activities under visible light irradiation are still low and should be enanced. The improvement of photocatalytic activities under visible light irradiation was achieved by enlargement of interfacial contact between titania and NPs of noble metals, extension of photoabsorption ranges (by preparation of NPs of various sizes and shapes or composed of two kinds of noble metals), and by deposition of noble metals NPs on faceted titania, i.e., octahedral (OAPs) and decahedral (DAPs). Plasmonic photocatalysts composed of titania and NPs of silver, gold or copper showed also high antiseptic properties under visible light irradiation, due to possible synergism of antiseptic properties of noble metals and photodisinfection properties of photocatalyst, since reactive oxygen species or photogenerated holes are formed on the surface of irradiated semiconductor.

scholarly journals Gemini surfactant assisted synthesis of mesoporous Mn/Mg bimetal doped TiO2 nanomaterial: Characterization and photocatalytic activity studies under visible light irradiation

2021 ◽  
Author(s):  
Sankara Rao Miditana ◽  
Siva Rao Tirukkovalluri ◽  
Imandi Manga Raju ◽  
Shaik Abdul Alim ◽  
Genji Jaishree ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Surface Area ◽  
Visible Light Irradiation ◽  
Gemini Surfactant ◽  
Light Irradiation ◽  
Methyl Red ◽  
X Ray ◽  
Ft Ir

Abstract The present work mainly aimed to synthesize different weight percentages (0.25-1.00 wt%) of Manganese (Mn2+) and Magnesium (Mg2+) bimetal ions doped TiO2 nanomaterial assisted with different weight percentages (5-15 wt%) of Gemini surfactant (GS) using sol-gel method. The bimetal doped and undoped TiO2 photocatalysts were characterized by X-ray Diffraction, Scanning Electron Microscopy, Energy Dispersive X-ray Spectroscopy, Fourier Transform Infrared Spectroscopy (FT-IR), UV-Visible Diffused Reflectance Spectroscopy, Transmission Electron Microscopy, Brunauer-Emmett-Teller surface area analyzer, and Photoluminescence Spectroscopy. Characterization results revealed that mesoporous multi-particle anatase TiO2 nanoparticles with a narrowed band gap, small particle size, and high surface area were formed due to the combined effect of Mn2+/Mg2+ bimetal ions doping and effective encapsulation of GS over the initially formed TiO2 nanoparticles. The surface elemental composition of the 0.25 wt% Mn2+ and 1.00 wt% Mg2+ bimetal doped TiO2 in the presence of 10 wt% of GS (after calcination) revealed the presence of both the metal dopants Mn2+ and Mg2+ along with the Ti and O and their chemical interactions were further confirmed by FT-IR results. The photocatalytic activity of these catalysts was assessed by the degradation of Methyl Red using visible light irradiation. To understand the effect of different reaction parameters on the photocatalytic activity of the nanocatalysts such as the dopant concentration, surfactant concentration, catalyst dosage, solution pH, and initial dye concentrations were investigated and optimized to achieve the best performance. The photoluminescence results conclude that OH radicals are the crucial reactive species responsible for oxidative photocatalytic degradation of Methyl Red.

Highly photodegradation of organic dye pollutant RhB using TiO2-modified reduced graphene oxide

2021 ◽  
Author(s):  
Rahmat Hidayat ◽  
Sayekti Wahyuningsih ◽  
Ganjar Fadillah ◽  
Ari Handono Ramelan
Keyword(s):  
Graphene Oxide ◽  
Visible Light ◽  
Reduced Graphene Oxide ◽  
Surface Area ◽  
Visible Light Irradiation ◽  
Light Irradiation ◽  
X Ray Diffraction ◽  
Process Step ◽  
Photodegradation Efficiency ◽  
Reduced Graphene

Abstract TiO2-modified reduced graphene oxide (TiO2-rGO) has been studied in one-process step synthesis via the hydrothermal method. In this study, the various concentrations of rGO were investigated and characterized by fourier transform infrared (FTIR), x-ray diffraction (XRD), scanning electron microscope (SEM), surface area analyzer (SAA), thermogravimetric analysis/differential thermal analysis (TGA/DTA), and spectroscopy UV-Vis. In addition, the photodegradation of rhodamine-B was studied by a batch system under visible light irradiation at wavelength 554 nm. The optimum experimental results showed that the presence of rGO in TiO2 nanostructures could improve the specific surface area until 248.58 m2 g− 1 and enhanced the photodegradation efficiency until 70.66% under visible light irradiation. The photocatalyst stability was evaluated for five cycles experiment and the performance have reduced 6.58% efficiency.

scholarly journals Photocatalytic activity of BiFeO3/ZnFe2O4 nanocomposites under visible light irradiation

RSC Advances ◽  
2018 ◽  
Vol 8 (13) ◽  
pp. 6988-6995 ◽  
Author(s):  
B. Safizade ◽  
S. M. Masoudpanah ◽  
M. Hasheminiasari ◽  
A. Ghasemi
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Visible Light Irradiation ◽  
Light Irradiation ◽  
Photocatalytic Efficiency

BiFeO3-25 wt% ZnFe2O4 exhibits a low specific surface area, high magnetization, and maximum photocatalytic efficiency of 97%.

Tuning the Photocatalytic Performance of Tungsten Oxide by Incorporating Cu3V2O8 Nanoparticles for H2 Evolution Under Visible Light Irradiation

2019 ◽  
Vol 17 (1) ◽  
Author(s):  
M. B. Tahir ◽  
T. Iqbal ◽  
I. Zeba ◽  
A. Hasan ◽  
Shabbir Muhammad ◽  
...  
Keyword(s):  
Visible Light ◽  
Surface Area ◽  
Hydrogen Evolution ◽  
Visible Light Irradiation ◽  
Charge Separation ◽  
Photocatalytic Performance ◽  
Green Energy ◽  
Light Irradiation ◽  
Composite Sample ◽  
Average Crystalline Size

Abstract The green energy production through water splitting under visible light irradiation has become an emerging challenge in the 21st century. Photocatalysis, being a cost-competitive and efficient technique, has grabbed much more attention for environmental applications, especially for hydrogen evolution. In this article, the hybrid Cu3V2O8-WO3 nanostructures were prepared through the hydrothermal method by using copper acetate, ammonium metavanadate, and Na2WO4 · 2H2O as precursors. The varying contents of Cu3V2O8 in WO3 were 0.2%, 0.5%, 1.0%, 2.0%, and 3.0%. The X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET), UV-Vis, and photoluminescence (PL) emission spectroscopy were used to investigate the structural, morphological, surface area, and optical properties of prepared samples. The average crystalline size of the pure WO3 ranges from 10 to 15 nm and 70 to 195 nm for an optimal composite sample. The structural phase of the hybrid WO3-Cu3V2O8 nanoparticles was found to transfer from monoclinic to hexagonal by incorporating the Cu3V2O8 contents. The enhanced photocatalytic performance for hydrogen evolution was observed for 2% Cu3V2O8-WO3 composite sample. The key to this enhancement lies at the heterojunction interface, where charge separation occurs. In addition, the excellent photocatalytic activity was attributed to a higher surface area, efficient charge separation, and extended visible light absorption. This work provides an in-depth understanding of efficient separation of charge carriers and transfer processes and steer charge flow for efficient solar-to-chemical energy applications.

scholarly journals CdS aerogels as efficient photocatalysts for degradation of organic dyes under visible light irradiation

2017 ◽  
Vol 4 (9) ◽  
pp. 1451-1457 ◽  
Author(s):  
Lasantha Korala ◽  
Jason R. Germain ◽  
Erica Chen ◽  
Irina R. Pala ◽  
Da Li ◽  
...  
Keyword(s):  
Visible Light ◽  
Surface Area ◽  
Visible Light Irradiation ◽  
Organic Dyes ◽  
Light Irradiation ◽  
Light Activation ◽  
Interfacial Surface ◽  
Visible Light Activation

CdS aerogel photocatalysts enable a high-interfacial surface area for analyte reactivity and visible light activation.

Preparation and Characterization of Nitrogen Doped TiO2 Nanoparticles as an Effective Catalyst in Photodegradation of Phenol under Visible Light

2014 ◽  
Vol 875-877 ◽  
pp. 28-33 ◽  
Author(s):  
Armineh Hassanvand ◽  
Morteza Sohrabi ◽  
Sayed Javid Royaee ◽  
Morteza Jafarikajour
Keyword(s):  
Visible Light ◽  
Tio2 Nanoparticles ◽  
Surface Area ◽  
Visible Light Irradiation ◽  
Light Irradiation ◽  
Bet Surface Area ◽  
Doped Tio2 ◽  
X Ray ◽  
Nitrogen Doped ◽  
Degussa P25

Nitrogen-doped TiO2 nanoparticles of commercial Degussa P25 have been prepared via a direct impregnation reaction using ammonium hydroxide solution as nitrogen source. The Samples were characterized by X-ray diffraction (XRD), BET surface area BJH pore charecterization and scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDX). The results demonstrated that the nitrogen-doped TiO2 nanoparticles had a crystallite size 70.8 nm and a specific surface area of 6.4 m2/g with average pore diameter of 23.3 nm consisting mainly of titanium and oxygen. The photocatalyst activity was determined by degradation of phenol in an impinging stream reactor under visible light irradiation (λ> 400 nm). N-TiO2 catalyst exhibited higher photocatalytic activity in comparison with Degussa P25 under visible light irradiation.

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