Improved light absorption and photocatalytic activity of Zn,N-TiO2−x rich in oxygen vacancies synthesized by nitridation and hydrogenation

2015 ◽  
Vol 39 (4) ◽  
pp. 2417-2420 ◽  
Author(s):  
Yidong Hu ◽  
Gang Chen ◽  
Chunmei Li ◽  
Yaoguang Yu ◽  
Jingxue Sun ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Light Absorption ◽  
Oxygen Vacancies ◽  
High Photocatalytic Activity

Compared with N-TiO2 and Zn,N-TiO2 samples, Zn,N-TiO2−x rich in oxygen vacancies demonstrates high photocatalytic activity.

scholarly journals Visible-light photocatalysis on C-doped ZnO derived from polymer-assisted pyrolysis

RSC Advances ◽  
2015 ◽  
Vol 5 (35) ◽  
pp. 27690-27698 ◽  
Author(s):  
Ahmad S. Alshammari ◽  
Lina Chi ◽  
Xiaoping Chen ◽  
Abdulaziz Bagabas ◽  
Denis Kramer ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Light Absorption ◽  
Oxygen Vacancies ◽  
Charge Carriers ◽  
Visible Light Photocatalysis ◽  
Visible Light Absorption ◽  
C Doping ◽  
Doped Zno

Heavy C-doping can effectively enhance visible-light absorption yet exhibited lower visible-light-responsive photocatalytic activity due to significant recombination of photogenerated charge carriers caused by C-dopant and oxygen vacancies.

Visible-Light Driven LaNiO3 Nanosized Photocatalysts Prepared by a Sol-Gel Process

2011 ◽  
Vol 279 ◽  
pp. 83-87 ◽  
Author(s):  
Pei Song Tang ◽  
He Sun ◽  
Feng Cao ◽  
Jin Tian Yang ◽  
Sheng Liang Ni ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Methyl Orange ◽  
Visible Light ◽  
Light Absorption ◽  
Diffuse Reflectance Spectroscopy ◽  
Sol Gel ◽  
High Photocatalytic Activity ◽  
Visible Light Absorption ◽  
Average Grain Size ◽  
Sol Gel Process

The LaNiO3 nanoparticles were prepared by a sol-gel process. The LaNiO3 nanoparticles were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-Vis diffuse reflectance spectroscopy (DRS). XRD and SEM demonstrate the successful synthesis of single phase perovskite LaNiO3 and an average grain size of 80 nm in diameter. It was found that the as-prepared LaNiO3 shows strong visible-light absorption with absorption onset of 545 nm, indicating a narrow optical band gap of 2.28 eV. Consequently, LaNiO3 nanoparticles show high visible-light photocatalytic activity for decomposition of methyl orange in comparison with the commercial Degussa P25. The photocatalytic experiment shows the high photocatalytic activity for the decomposition of methyl orange under visible-light irradiation, which is attributed to the strong visible-light absorption.

scholarly journals Magnetic resonance study of annealed and rinsed N-doped TiO2 nanoparticles

2013 ◽  
Vol 11 (12) ◽  
pp. 1996-2004 ◽  
Author(s):  
Niko Guskos ◽  
Janusz Typek ◽  
Aleksander Guskos ◽  
Grzegorz Zolnierkiewicz ◽  
Pawel Berczynski ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Light Absorption ◽  
Oxygen Vacancies ◽  
Diffuse Reflectance Spectroscopy ◽  
Epr Spectra ◽  
Magnetic Clusters ◽  
Paramagnetic Resonance ◽  
Doped Tio2 ◽  
Phenol Decomposition ◽  
Higher Temperature

AbstractNanoparticles of nitrogen-modified TiO2 (N-doped TiO2) calcined at 300°C and 350°C, have been prepared with and without water rinsing. Samples were characterized by x-ray diffractrometry (XRD) and optical spectroscopy. The electron paramagnetic resonance (EPR) spectra from centers involving oxygen vacancies were recorded for all samples. These could be attributed to paramagnetic surface centers of the hole type, for example to paramagnetic oxygen radicals O−, O2−etc. The concentration of these centers increased after water rising and it further increased for samples annealed at higher temperature. Additionally, for samples calcined at 300°C, and calcined at 350°C and rinsed, the EPR spectra evidenced the presence of magnetic clusters of Ti3+ ions. The photocatalytic activity of samples was studied towards phenol decomposition under unltraviolet-visible (UV-Vis) irradiation. It was found that, in comparison to the starting materials, the rinsed materials showed increased photocatalytic activity towards phenol oxidation. The light absorption (UV-Vis/DRS) as well as surface Fourier transform infrared/diffuse reflectance spectroscopy (FTIR/DR) studies confirmed a significantly enhanced light absorption and the presence of nitrogen groups on the photocatalysts surfaces, respectively. A significant increase of concentration of paramagnetic centers connected with oxygen vacancies after water rising has had an essential influence on increasing their photocatalytic activity.

Synthesis and Enhanced Photocatalytic Activity of Black Porous Zr-doped TiO2 Monoliths

NANO ◽  
2016 ◽  
Vol 11 (06) ◽  
pp. 1650068 ◽  
Author(s):  
Jimin Du ◽  
Huiming Wang ◽  
Huijuan Chen ◽  
Menghe Yang ◽  
Xiaoling Lu ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Oxygen Vacancies ◽  
Dye Degradation ◽  
Anatase Phase ◽  
Sol Gel ◽  
Hydrogen Atmosphere ◽  
High Photocatalytic Activity ◽  
Polystyrene Spheres ◽  
Narrow Bandgap ◽  
Visible Irradiation

Black Porous Zr-doped TiO2 monoliths were successfully synthesized by a combined route including sol–gel method with polystyrene spheres as template followed by calcination at high temperature in the presence of oxygen. As-synthesized samples were then treated in hydrogen atmosphere at 500[Formula: see text]C for 6[Formula: see text]h to obtain black Porous Zr-doped TiO2 monoliths. This as-synthesized black porous Zr-doped TiO2 composite showed relatively narrow bandgap compared to the pure anatase phase of TiO2, which may have its origin from the contributions from the Zr impurity and oxygen vacancies. The photocatalytic activity of the black porous Zr-doped TiO2 monolith was examined by carrying out the dye degradation on Rhodamine B under visible irradiation. Our experimental results indicate that black porous 0.9% Zr-doped TiO2 sample exhibits high photocatalytic activity with the photodecomposition of 95.25% under visible irradiation for 120[Formula: see text]min.

scholarly journals Photocatalytic Degradation of Sulfamethoxazole, Nitenpyram and Tetracycline by Composites of Core Shell g-C3N4@ZnO, and ZnO Defects in Aqueous Phase

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2609
Author(s):  
Godfred Kwesi Teye ◽  
Jingyu Huang ◽  
Yi Li ◽  
Ke Li ◽  
Lei Chen ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Photocatalytic Activity ◽  
Light Absorption ◽  
Charge Separation ◽  
Absorption Efficiency ◽  
High Photocatalytic Activity ◽  
High Load ◽  
Core Shell ◽  
Visible Light Absorption ◽  
Load Separation

The synthesis of photocatalysts with high charge separation and transfer efficiency are of immense significance in the process of using photocatalysis technology for wastewater treatment. In this study core shell g-C3N4@ZnO, and ZnO defects photocatalysts presented an improved morphology in its characterization using techniques such as SEM, DRS, PL, MS, EIS, and XRD, and enhanced photodegradation of sulfamethoxazole, Nitenpyram and Tetracycline. Different composites were obtained as confirmed by the various characterization techniques studied, including core shell g-C3N4@ZnO, and ZnO defects photocatalyst. The synthesized photocatalysts showed high visible light absorption efficiency within a range of ~655 to 420 nm. Core shell g-C3N4@ZnO, and ZnO defects photocatalysts demonstrated high photocatalytic activity ascribed to high load separation and transition as shown in PL, Photocurrent reaction and EIS. It is understandable that core shell g-C3N4@ZnO, and ZnO defects photocatalysts have been confirmed to be one of the ultimate promising entrants for photocatalyst scheming.

Rational Designs on TiO2-based Nanocomposites for Solar Photocatalytic Purification

2011 ◽  
Vol 1352 ◽  
Author(s):  
Shanmin Gao ◽  
Tao Xu
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Oxygen Vacancies ◽  
High Photocatalytic Activity ◽  
Light Radiation ◽  
Large Specific Surface Area ◽  
Free Process ◽  
Light Region ◽  
Continuous States ◽  
Template Free

ABSTRACTWe report an template-free process to fabricate S-C-codoped and (I2)n-C-codoped meso/nanoporous TiO2 nanocrystallites. Methylene blue solutions are used as a model pollute to evaluate the sorption and photocatalytic activity of the samples under visible light radiation. The high photocatalytic activity in visible light region of our samples is attributed to numerous oxygen vacancies, large specific surface area and the continuous states in the band gap of TiO2 introduced by I2 or S doping.

scholarly journals In situ strategy to prepare PDPB/SnO2 p–n heterojunction with a high photocatalytic activity

RSC Advances ◽  
2017 ◽  
Vol 7 (39) ◽  
pp. 24064-24069 ◽  
Author(s):  
Yuhang Wang ◽  
Yuanxin Deng ◽  
Linggang Fan ◽  
Yu Zhao ◽  
Bin Shen ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Rhodamine B ◽  
Light Absorption ◽  
Charge Separation ◽  
High Photocatalytic Activity ◽  
Growth Strategy ◽  
Solar Light ◽  
Photodegradation Rate

PDPB/SnO2 heterojunction has been successfully synthesized by an in situ growth strategy, which displays a narrowed bandgap, enhanced solar light absorption, excellent charge separation and improved solar-driven photodegradation rate of Rhodamine B.

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>

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