Highly active Ta2O5 microcubic single crystals: facet energy calculation, facile fabrication and enhanced photocatalytic activity of hydrogen production

2016 ◽  
Vol 4 (42) ◽  
pp. 16562-16568 ◽  
Author(s):  
Hao Tu ◽  
Leilei Xu ◽  
Fangzhi Mou ◽  
Jianguo Guan
Keyword(s):  
Photocatalytic Activity ◽  
Hydrogen Production ◽  
Single Crystals ◽  
High Energy ◽  
Large Percentage ◽  
Energy Calculation ◽  
Topological Transformation ◽  
Highly Active ◽  
Photocatalytic Activities ◽  
Facile Fabrication

Ta2O5 single crystals microcubic with large percentage of high-energy {001} facets are fabricated through topological transformation exhibit enhanced photocatalytic activities.

scholarly journals Highly Active Rare-Earth-Metal La-Doped Photocatalysts: Fabrication, Characterization, and Their Photocatalytic Activity

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
S. Anandan ◽  
Y. Ikuma ◽  
V. Murugesan
Keyword(s):  
Photocatalytic Activity ◽  
High Surface ◽  
Sol Gel ◽  
Earth Metal ◽  
High Photocatalytic Activity ◽  
Highly Active ◽  
Photocatalytic Activities ◽  
Doped Zno ◽  
Photonic Efficiency ◽  
La Doped

Efficient La-doped TiO2photocatalysts were prepared by sol-gel method and extensively characterized by various sophisticated techniques. The photocatalytic activity of La-doped TiO2was evaluated for the degradation of monocrotophos (MCPs) in aqueous solution. It showed higher rate of degradation than pure TiO2for the light of wavelength of 254 nm and 365 nm. The rate constant of TiO2increases with increasing La loading and exhibits maximum rate for 1% La loading. The photocatalytic activities of La-doped TiO2are compared with La-doped ZnO; the reaction rate of the former is ~1.8 and 1.1 orders higher than the latter for the lights of wavelength 254 nm and 365 nm, respectively. The relative photonic efficiency of La-doped TiO2is relatively higher than La-doped ZnO and commercial photocatalysts. Overall, La-doped TiO2is the most active photocatalyst and shows high relative photonic efficiencies and high photocatalytic activity for the degradation of MCP. The enhanced photocatalytic activity of La-doped TiO2is mainly due to the electron trapping by lanthanum metal ions, small particle size, large surface area, and high surface roughness of the photocatalysts.

scholarly journals The effect of anatase crystal morphology on the photocatalytic conversion of NO by TiO2-based nanomaterials

2012 ◽  
Vol 10 (4) ◽  
pp. 1183-1198 ◽  
Author(s):  
Marco Abreu ◽  
Edisson Morgado ◽  
Paula Jardim ◽  
Bojan Marinkovic
Keyword(s):  
Photocatalytic Activity ◽  
Crystal Morphology ◽  
Hydrothermal Reaction ◽  
High Energy ◽  
Proton Exchange ◽  
Acid Media ◽  
Tio2 Anatase ◽  
Vis Spectroscopy ◽  
Photocatalytic Activities ◽  
Low Activity

AbstractHydrogen titanate nanotubes (H-TTNT) were synthesized by the alkali hydrothermal method followed by proton exchange and then submitted either to thermal treatment or to acid hydrothermal reaction to generate TiO2-anatase nanocrystals of different morphologies. The samples were characterized by XRPD, TGA, sulfur analysis, N2 physisorption, UV-Vis spectroscopy and TEM. Their photocatalytic activities were determined by measuring the NO conversion in inert gas stream passed through the powder catalyst bed under UV radiation. Incomplete transformation into anatase resulted in nanomaterials with low activity due to coexistence with H-TTNT or TiO2-B precursors. Anatase specimens derived from H-TTNT aged in strong sulfuric acid media contained equidimensional nanoparticles, but retention of sulfate negatively affected their photocatalytic activity. Combining milder acidic pH with higher aging temperature, allowed synthesis of a sulfate free anatase with the same optical properties and specific surface area as the counterpart produced by calcination of H-TTNT at 550°C; however, the former exhibited truncated bi-pyramid nanocrystals and the other adopted the form of nanorods. This latter showed the highest photocatalytic activity for NO abatement, outperforming the benchmark photocatatyst TiO2-P25; this improved activity was tentatively ascribed to the maximization of high energy {001} facets in anatase nanorods formed during calcination of H-TTNT.

scholarly journals Preparation ofNaTaO3by Spray Pyrolysis and Evaluation of Apparent Photocatalytic Activity for Hydrogen Production from Water

2008 ◽  
Vol 2008 ◽  
pp. 1-8 ◽  
Author(s):  
Hyun Woo Kang ◽  
Eun-Jung Kim ◽  
Seung Bin Park
Keyword(s):  
Photocatalytic Activity ◽  
Quantum Yield ◽  
Hydrogen Production ◽  
Spray Pyrolysis ◽  
Uv Light ◽  
Precursor Solution ◽  
Photocatalytic Reactor ◽  
Photocatalytic Activities ◽  
Uv Lamp ◽  
Spray Pyrolysis Process

NaTaO3photocatalyst was prepared by spray pyrolysis process and tested as photocatalyst for water splitting under UV light. Precursor solution was prepared fromNaNO3andTa(OC2H5)5in nitric acid solution and spray-pyrolyzed in air at between 973 and 1273 K. Considerable enhancement of photocatalytic activity was achieved by loading0.05∼0.2 wt% of NiO on the surface ofNaTaO3. The NiO loading was more effective on theNaTaO3synthesized by spray pyrolysis in comparison with that synthesized by solid-state reaction. The quantum yield (QY) ofNiO/NaTaO3photocatalyst was measured by chemical actinometry using potassium ferrioxalate and compared with the apparent photocatalytic activities (APA) which would be more useful for the purpose of photocatalytic reactor design than the quantum yield. The apparent photocatalytic activity (APA) was defined by the rate of hydrogen production divided by weight of catalyst, volume of reactant mixture, duration of irradiation, and power of UV lamp. The validity of the apparent photocatalytic activity (APA) was discussed based on our results and reported activities ofNaTaO3photocatalyst loaded with or without NiO.

Visible-Light Induced Photocatalytic Activity of Vanadium and Nitrogen Co-Doped SrTiO3

2009 ◽  
Vol 147-149 ◽  
pp. 851-855 ◽  
Author(s):  
Jin Shu Wang ◽  
Hui Li ◽  
Hong Yi Li ◽  
Shu Yin ◽  
Tsugio Sato
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
High Energy ◽  
Nitrogen Doped ◽  
Near Ultraviolet ◽  
Ultraviolet Range ◽  
Photocatalytic Activities ◽  
Milling Method ◽  
Co Doped ◽  
Visible Light Photocatalytic

Vanadium doped, nitrogen doped, and vanadium and nitrogen co-doped SrTiO3 powders with size of 20-30 nm in diameter were prepared by high energy milling method respectively. It was found that compared with those of pure SrTiO3, the photocatalytic activities of these three doped SrTiO3 samples for decomposing NO under visible light (λ>400 nm) and near ultraviolet light (λ>290 nm) irradiation were improved, and the co-doped sample exhibited the highest photocatalytic activity. 43.2% NO could be eliminated under the irradiation of light with wavelength larger than 400nm, about 3 times higher than that by pure SrTiO3. The photocatalytic activity of this sample near ultraviolet range is about 1.7 times higher than that of pure SrTiO3. The high visible light photocatalytic activity of this substance may be due to the high visible light absorption and large specific surface area.

Urea-Catalyzed Functionalization of Unactivated C–H Bonds

2020 ◽  
Author(s):  
Alex L. Bagdasarian ◽  
Stasik Popov ◽  
Benjamin Wigman ◽  
Wenjing Wei ◽  
woojin lee ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Organic Synthesis ◽  
High Energy ◽  
Acid Catalysts ◽  
Potential Utility ◽  
New Paradigm ◽  
Lewis Acid Catalysts ◽  
Reaction Conditions ◽  
Highly Active ◽  
Acidic Nature

Herein we report the 3,5bistrifluoromethylphenyl urea-catalyzed functionalization of unactivated C–H bonds. In this system, the urea catalyst mediates the formation of high-energy vinyl carbocations that undergo facile C–H insertion and Friedel–Crafts reactions. We introduce a new paradigm for these privileged scaffolds where the combination of hydrogen bonding motifs and strong bases affords highly active Lewis acid catalysts capable of ionizing strong C–O bonds. Despite the highly Lewis acidic nature of these catalysts that enables triflate abstraction from sp<sup>2</sup> carbons, these newly found reaction conditions allow for the formation of heterocycles and tolerate highly Lewis basic heteroaromatic substrates. This strategy showcases the potential utility of dicoordinated vinyl carbocations in organic synthesis.<br>

Urea-Catalyzed Functionalization of Unactivated C–H Bonds

2020 ◽  
Author(s):  
Alex L. Bagdasarian ◽  
Stasik Popov ◽  
Benjamin Wigman ◽  
Wenjing Wei ◽  
woojin lee ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Organic Synthesis ◽  
High Energy ◽  
Acid Catalysts ◽  
Potential Utility ◽  
New Paradigm ◽  
Lewis Acid Catalysts ◽  
Reaction Conditions ◽  
Highly Active ◽  
Acidic Nature

Herein we report the 3,5bistrifluoromethylphenyl urea-catalyzed functionalization of unactivated C–H bonds. In this system, the urea catalyst mediates the formation of high-energy vinyl carbocations that undergo facile C–H insertion and Friedel–Crafts reactions. We introduce a new paradigm for these privileged scaffolds where the combination of hydrogen bonding motifs and strong bases affords highly active Lewis acid catalysts capable of ionizing strong C–O bonds. Despite the highly Lewis acidic nature of these catalysts that enables triflate abstraction from sp<sup>2</sup> carbons, these newly found reaction conditions allow for the formation of heterocycles and tolerate highly Lewis basic heteroaromatic substrates. This strategy showcases the potential utility of dicoordinated vinyl carbocations in organic synthesis.<br>

Synthesis of PbS Intercalated K4Nb6O17 Composite and Its Photocatalytic Activity for Hydrogen Production

2012 ◽  
Vol 27 (9) ◽  
pp. 933-938
Author(s):  
Wen-Quan CUI ◽  
Yan-Fei LIU ◽  
Jin-Shan HU ◽  
Li LIU ◽  
Ying-Hua LIANG
Keyword(s):  
Photocatalytic Activity ◽  
Hydrogen Production

Bifunctional single-atomic Mn sites for energy-efficient hydrogen production

Nanoscale ◽  
2021 ◽  
Author(s):  
Xianyun Peng ◽  
Junrong Hou ◽  
Yuying Mi ◽  
Jiaqiang Sun ◽  
Gaocan Qi ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Energy Saving ◽  
Hydrogen Evolution Reaction ◽  
Energy Efficient ◽  
Low Cost ◽  
Clean Energy ◽  
H2 Production ◽  
Energy Technology ◽  
Highly Active ◽  
Clean Energy Technology

Electrocatalytic hydrogen evolution reaction (HER) for H2 production is essential for future renewable and clean energy technology. Screening energy-saving, low-cost, and highly active catalysts efficiently, however, is still a grand...

scholarly journals Exploring Flaring Behaviour on Low Mass Stars, Solar-type Stars and the Sun

2019 ◽  
Vol 15 (S354) ◽  
pp. 384-391
Author(s):  
L. Doyle ◽  
G. Ramsay ◽  
J. G. Doyle ◽  
P. F. Wyper ◽  
E. Scullion ◽  
...  
Keyword(s):  
High Energy ◽  
The Sun ◽  
Low Mass Stars ◽  
Highly Active ◽  
Rotation Phase ◽  
Solar Type ◽  
Low Mass ◽  
Insight Into ◽  
Reconnection Model ◽  
High Cadence

AbstractWe report on our project to study the activity in both the Sun and low mass stars. Utilising high cadence, Hα observations of a filament eruption made using the CRISP spectropolarimeter mounted on the Swedish Solar Telescope has allowed us to determine 3D velocity maps of the event. To gain insight into the physical mechanism which drives the event we have qualitatively compared our observation to a 3D MHD reconnection model. Solar-type and low mass stars can be highly active producing flares with energies exceeding erg. Using K2 and TESS data we find no correlation between the number of flares and the rotation phase which is surprising. Our solar flare model can be used to aid our understanding of the origin of flares in other stars. By scaling up our solar model to replicate observed stellar flare energies, we investigate the conditions needed for such high energy flares.

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