Effect of Hydrogen Peroxide on the Photocatalytic Decomposition of 4-Nitrophenol over TiO2/Cr-Ti- MCM-41 Catalysts in Visible Light

2005 ◽  
Vol 486-487 ◽  
pp. 13-16
Author(s):  
Gun Dae Lee ◽  
Y.J. Do ◽  
Seong Soo Park ◽  
Seong Soo Hong
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Light Absorption ◽  
Photocatalytic Decomposition ◽  
Electron Hole ◽  
Visible Light Absorption ◽  
Photocatalytic Activities ◽  
Hole Recombination ◽  
Mcm 41 ◽  
Uv Range

Cr, Ti-substituted TiO2-loaded MCM-41 (TiO2/Cr-Ti-MCM-41) catalysts were prepared, and their photocatalytic activities for decomposition of 4-nitrophenol (4-NP) in visible light were studied. The effect of H2O2 on the photocatalytic decomposition of 4-NP was investigated. Tisubstituted MCM-41 exhibited an absorption in UV range, and the incorporation of both Ti and Cr in the MCM-41 framework created visible light absorption. The visible light absorption capability of TiO2/Cr-Ti-MCM-41 increased with increasing TiO2 loading. The photocatalytic activity of Cr- Ti-MCM-41 for degradation of 4-NP in visible light increased with increasing TiO2 loading up to 33 wt%. The addition of H2O2 enhanced the photocatalytic activity of 33 wt% TiO2/Cr-Ti-MCM-41 for decomposition of 4-NP in visible light. H2O2 was found to promote the adsorption of 4-NP on the Cr-Ti-MCM-41 surface, leading to increased reaction rate. In addition, H2O2 may act as an electron acceptor during photocatalytic reaction, thereby lowering the electron-hole recombination and increasing the efficiency of hole utilization.

scholarly journals A metal-free 3C-SiC/g-C3N4 composite with enhanced visible light photocatalytic activity

RSC Advances ◽  
2017 ◽  
Vol 7 (63) ◽  
pp. 40028-40033 ◽  
Author(s):  
Hao Xu ◽  
Zhixing Gan ◽  
Weiping Zhou ◽  
Zuoming Ding ◽  
Xiaowei Zhang
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Light Absorption ◽  
Carbon Nitride ◽  
Photocatalytic Performance ◽  
Photogenerated Electron ◽  
Electron Hole ◽  
Visible Light Absorption ◽  
Metal Free ◽  
Visible Light Photocatalytic

Insufficient visible light absorption and fast recombination of the photogenerated electron–hole pairs have seriously hampered the photocatalytic performance of graphitic carbon nitride (g-C3N4) up to now.

scholarly journals New insight into effects of 4d transition metals doping on the photocatalytic activities of anatase TiO2(101) surface

2020 ◽  
Author(s):  
Yuehong Ren ◽  
Qingzhen Han ◽  
Qiaozhi Su ◽  
Jie Yang ◽  
Yuehong Zhao ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Light Absorption ◽  
Interband Transition ◽  
Energy Bands ◽  
Tio2 Photocatalysts ◽  
Visible Light Absorption ◽  
Photocatalytic Activities ◽  
Metal Phase Transition ◽  
Insight Into

Aiming at improving the visible-light photocatalytic activities of TiO2(101) surface (TiOS) we make an in-dept study on the TiOS doped with 4d transition metal (TM) atoms. It is shown that the 4d TM dopings can not only produce new impurity energy bands in the bandgap but also result in the semiconductor-metal phase transition. Consequently, the visible-light absorption is strongly strengthened due to the dopings of Y, Zr, Nb, Mo, and Ag, while it is only weakly improved for Tc, Ru, Rh, Pd, and Cd dopings. The improvement in visible-light absorption can be attributed to the intraband or interband transition of electrons. Moreover, the photocatalytic activities are explored, and we find Y and Ag dopings can effectively enhance the photocatalytic activity of TiOS. Thus the mechanism of improving photocatalytic activity of TiOS has been clearly addressed, which is beneficial to further experimental and theoretical researches on TiO2 photocatalysts.

An inverse opal TiO2/g-C3N4 composite with a heterojunction for enhanced visible light-driven photocatalytic activity

2019 ◽  
Vol 48 (10) ◽  
pp. 3486-3495 ◽  
Author(s):  
Juying Lei ◽  
Bin Chen ◽  
Weijia Lv ◽  
Liang Zhou ◽  
Lingzhi Wang ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Light Absorption ◽  
Separation Efficiency ◽  
Photogenerated Electron ◽  
Absorption Efficiency ◽  
Inverse Opal ◽  
Electron Hole ◽  
Visible Light Absorption ◽  
Visible Light Driven

An inverse opal TiO2/g-C3N4 composite with excellent photogenerated electron–hole separation efficiency and enhanced visible light absorption efficiency was constructed.

Impact of Rutile Fraction on TiO2 Visible-Light Absorption and Visible-Light-Induced Photocatalytic Activity

2018 ◽  
Author(s):  
David Maria Tobaldi ◽  
Luc Lajaunie ◽  
ana caetano ◽  
nejc rozman ◽  
Maria Paula Seabra ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Light Absorption ◽  
Solid Phase ◽  
Diffraction Method ◽  
Band Alignment ◽  
Quantitative Phase Analysis ◽  
Transmission Microscopy ◽  
Visible Light Absorption ◽  
X Ray

<div>Titanium dioxide is by far the most utilised semiconductor material for photocatalytic applications. Still, it is transparent to visible-light. Recently, it has been proved that a type-II band alignment for the rutile−anatase mixture would improve its visible-light absorption.</div><div>In this research paper we thoroughly characterised the real crystalline and amorphous phases of synthesised titanias – thermally treated at different temperatures to get distinct ratios of anatase-rutile-amorphous fraction – as well as that of three commercially available photocatalytic nano-TiO2. </div><div>The structural characterisation was done via advanced X-ray diffraction method, namely the Rietveld-RIR method, to attain a full quantitative phase analysis of the specimens. The microstructure was also investigated via an advanced X-ray method, the whole powder pattern modelling. These methods were validated combining advanced aberration-corrected scanning transmission microscopy and high-resolution electron energy-loss spectroscopy. The photocatalytic activity was assessed in the liquid- and gas-solid phase (employing rhodamine B and 4-chlorophenol, and isopropanol, respectively, as the organic substances to degrade) using a light source irradiating exclusively in the visible-range.</div><div>Optical spectroscopy showed that even a small fraction of rutile (2 wt%) is able to shift to lower energies the apparent optical band gap of an anatase-rutile mixed phase. But is this enough to attain a real photocatalytic activity promoted by merely visible-light?</div><div>We tried to give a reply to that question.</div><div>Photocatalytic activity results in the liquid-solid phase showed that a high surface hydroxylation led to specimen with superior visible light-induced catalytic activity (i.e. dye and ligand-to-metal charge transfer complexes sensitisation effects). That is: not photocatalysis <i>sensu-strictu</i>.</div><div>On the other hand, the gas-solid phase results showed that a higher amount of the rutile fraction (around 10 wt%), together with less recombination of the charge carriers, were more effective for an actual photocatalytic oxidation of isopropanol.</div>

scholarly journals Nickel and sulfur codoped TiO2 nanoparticles for efficient visible light photocatalytic activity

2021 ◽  
Author(s):  
Mehala Kunnamareddy ◽  
Ranjith Rajendran ◽  
Megala Sivagnanam ◽  
Ramesh Rajendran ◽  
Barathi Diravidamani
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Light Absorption ◽  
Fourier Transforms ◽  
Phase Particle ◽  
Energy Dispersive Spectrometer ◽  
Sol Gel ◽  
Bandgap Energy ◽  
Visible Light Absorption

AbstractIn this work, Nickel (Ni) and sulfur (S) codoped TiO2 nanoparticles were prepared by a sol-gel technique. The as-prepared catalyst was characterized using X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), FT-Raman spectroscopy, scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectra (DRS) for investigating crystal structure, crystal phase, particle size and bandgap energy of these samples. The photocatalytic performances of all the prepared catalysts have been investigated for the degradation of methylene blue (MB) under visible light irradiation. It was noticed that Ni-S codoped TiO2(Ni-S/TiO2) nanoparticles exhibited much higher photocatalytic activity compared with pure, Ni and S doped TiO2 due to higher visible light absorption and probable decrease in the recombination of photo-generated charges. It was decided that the great visible light absorption was created for codoped TiO2 by the formation of impurity energy states near both the edges of the collection, which works as trapping sites for both the photogenerated charges to decrease the recombination process.

Enhanced visible-active photocatalytic behaviors observed in Mn-doped BiFeO3

2018 ◽  
Vol 32 (17) ◽  
pp. 1850185 ◽  
Author(s):  
Yun-Hui Si ◽  
Yu Xia ◽  
Ya-Yun Li ◽  
Shao-Ke Shang ◽  
Xin-Bo Xiong ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Band Gap ◽  
Diffuse Reflectance Spectroscopy ◽  
X Ray Diffraction ◽  
Electron Hole ◽  
X Ray ◽  
Mn Doped ◽  
Hole Recombination ◽  
Narrow Band Gap Semiconductors

A series of BiFeO3 and BiFe[Formula: see text]Mn[Formula: see text]O3 (x = 0, 0.02, 0.04, 0.06, 0.08, 0.10) were synthesized by a hydrothermal method. The samples were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy (EDS) and UV–Vis diffuse reflectance spectroscopy, and their photocatalytic activity was studied by photocatalytic degradation of methylene blue in aqueous solution under visible light irradiation. The band gap of BiFeO3 was significantly decreased from 2.26 eV to 1.90 eV with the doping of Mn. Furthermore, the 6% Mn-doped BiFeO3 photocatalyst exhibited the best activity with a degradation rate of 94% after irradiation for 100 min. The enhanced photocatalytic activity with Mn doping could be attributed to the enhanced optical absorption, increment of surface reactive sites and reduction of electron–hole recombination. Our results may be conducive to design more efficient photocatalysts responsive to visible light among narrow band gap semiconductors.

Zr doped mesoporous LaTaON2 for efficient photocatalytic water splitting

2019 ◽  
Vol 7 (10) ◽  
pp. 5702-5711 ◽  
Author(s):  
Yawei Wang ◽  
Shu Jin ◽  
Guoxiang Pan ◽  
Zuxin Li ◽  
Long Chen ◽  
...  
Keyword(s):  
Visible Light ◽  
Water Splitting ◽  
Light Absorption ◽  
Visible Light Absorption ◽  
Photocatalytic Water Splitting ◽  
Photocatalytic Activities

Zr doping maintains the visible light absorption of LaTaON2 and contributes to enhanced photocatalytic activities for water splitting.

0D/3D-CdSe/Bi12TiO20 Pyramidal Heterostructure Photocatalysts for Enhanced Visible-Light Photocatalytic Activities

NANO ◽  
2017 ◽  
Vol 12 (06) ◽  
pp. 1750072 ◽  
Author(s):  
Tao Wang ◽  
Changchang Ma ◽  
Dan Wu ◽  
Xinlin Liu ◽  
Yang Liu ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Photocatalytic Degradation ◽  
High Stability ◽  
Photocatalytic Efficiency ◽  
Cdse Qds ◽  
Electron Hole ◽  
Adsorption Sites ◽  
Photocatalytic Activities ◽  
Visible Light Photocatalytic

In this paper, a novel heterostructure of 0D/3D-CdSe/Bi[Formula: see text]TiO[Formula: see text] pyramidal photocatalyst was synthesized and characterized. It exhibited significantly photocatalytic efficiency in photocatalytic degradation of the tetracycline than pure Bi[Formula: see text]TiO2 and CdSe and showed high stability. The enhanced photocatalytic activity might be attributed to the formation of heterostructure between CdSe QDs and 3D Bi[Formula: see text]TiO[Formula: see text], in which CdSe QDs served as electron trapper to improve the separation of photodegradation electron–hole pairs, and provided a number of active adsorption sites for the photogenerated of pollutants. The photocatalytic mechanism of 0D/3D-CdSe/Bi[Formula: see text]TiO[Formula: see text] pyramidal heterostructure was also proposed.

Visible Light Absorption Characteristics of M-Nitrogen (M= Mn, Fe, Co, Ni, Cu) Co-Doped Monodisperse TiO2 Microparticles

2015 ◽  
Vol 1806 ◽  
pp. 19-24 ◽  
Author(s):  
John E. Mathis
Keyword(s):  
Photocatalytic Activity ◽  
Transition Metals ◽  
Visible Light ◽  
Light Absorption ◽  
Sol Gel ◽  
Percent Level ◽  
Wide Distribution ◽  
Electromagnetic Spectrum ◽  
Visible Light Absorption ◽  
Co Doping

ABSTRACTThere is great interest in improving TiO2’s photocatalytic activity in the visible portion of electromagnetic spectrum. Recent work has shown that co-doping mesoporous TiO2 microparticles with a transition metal and nitrogen, hereby designated as (M,N) TiO2, significantly increases its visible light absorption. However, the hydrothermal method used to produce the microparticles creates a wide distribution in the size of the microparticles, which could affect the absorption properties. Recently, it has become possible to produce monodisperse, mesoporous TiO2 microparticles with engineered sizes using a hybrid sol-gel/hydrothermal technique. Further, it has also been shown that the size of monodisperse TiO2 microparticles affects the the photocatalytic activity.This study investigated whether using mondodisperse (M,N) TiO2 microparticles would further increase visible-light absorption for (M,N)TiO2. The first-row transition metals chosen for this study - Mn, Fe, Co, Ni, and Cu – have been characterized in the earlier (M,N) TiO2 UV-vis study, which was used as a baseline. The doping levels of the transition metals samples were set at the 2.5 percent level previously shown to be optimum for photocatalytic activity.

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