The crystalline/amorphous stacking structure of SnO2 microspheres for excellent NO photocatalytic performance

2021 ◽  
Author(s):  
Li Zhang ◽  
Ruobing Tong ◽  
Sagar E. Shirsath ◽  
Yanling Yang ◽  
Guohui Dong
Keyword(s):  
Photocatalytic Performance ◽  
Adsorption Sites ◽  
Stacking Structure

Novel crystalline/amorphous stacking structure of SnO2 microsphere provides excellent NO photocatalytic performance by separating the adsorption sites of NO and O2.

scholarly journals Significantly enhancement of sunlight photocatalytic performance of ZnO by doping with transition metal oxides

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alfonso E. Ramírez ◽  
Marly Montero-Muñoz ◽  
Lizbeth L. López ◽  
J. E. Ramos-Ibarra ◽  
Jose A. H. Coaquira ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Transition Metal ◽  
Metal Oxides ◽  
Transition Metal Oxides ◽  
High Performance ◽  
Photocatalytic Performance ◽  
Adsorption Sites ◽  
Surface Areas ◽  
Transmission Electron ◽  
Materials Used

AbstractIn this study we report, the synthesis of ZnO and its doping with Transition Metal Oxides -TMO-, such as Cr2O3, MnO2, FeO, CoO, NiO, Cu2O and CuO. Various characterization techniques were employed to investigate the structural properties. The X-ray diffraction (XRD) data and Rietveld refinement confirmed the presence of TMO phases and that the ZnO structure was not affected by the doping with TMO which was corroborated using transmission Electron microscopy (TEM). Surface areas were low due to blockage of adsorption sites by particle aggregation. TMO doping concentration in the range of 3.7–5.1% was important to calculate the catalytic activity. The UV–Visible spectra showed the variation in the band gap of TMO/ZnO ranging from 3.45 to 2.46 eV. The surface catalyzed decomposition of H2O2 was used as the model reaction to examine the photocatalytic activity following the oxygen production and the systems were compared to bulk ZnO and commercial TiO2-degussa (Aeroxyde-P25). The results indicate that the introduction of TMO species increase significantly the photocatalytic activity. The sunlight photocatalytic performance in ZnO-doped was greater than bulk-ZnO and in the case of MnO2, CoO, Cu2O and CuO surpasses TiO2 (P25-Degussa). This report opens up a new pathway to the design of high-performance materials used in photocatalytic degradation under visible light irradiation.

scholarly journals Light-driven oxygen evolution from water oxidation: TiO2 engineering in the performance of the immobilised photocatalysts

2021 ◽  
Author(s):  
Maria J. Sampaio ◽  
Zhipeng Yu ◽  
Joana C. Lopes ◽  
Pedro B. Tavares ◽  
Cláudia G. Silva ◽  
...  
Keyword(s):  
Oxygen Evolution ◽  
Water Oxidation ◽  
Photocatalytic Performance ◽  
Operation Mode ◽  
Sol Gel ◽  
Morphological Properties ◽  
Adsorption Sites ◽  
Oxygen Defects ◽  
Uv Led ◽  
Apparent Quantum Efficiency

Abstract Calcination treatments in the range of 500–900 ºC of TiO2 synthesised by the sol-gel resulted in materials with variable physicochemical (i.e., optical, specific surface area, crystallite size and crystalline phase) and morphological properties. The photocatalytic performance of the prepared materials was evaluated in the oxygen evolution reaction (OER) following UV-LED irradiation of aqueous solutions containing iron ions as sacrificial electron acceptors. The highest activity for water oxidation was obtained with the photocatalyst thermally treated at 700 ºC (TiO2-700). Photocatalysts with larger anatase to rutile ratio of the crystalline phases and higher surface density of oxygen vacancies (defects) displayed the best performance in OER. The oxygen defects at the photocatalyst surface have proven to be responsible for the enhanced photoactivity, acting as important active adsorption sites for water oxidation. Seeking technological application, water oxidation was accomplished by immobilising the photocatalyst with the highest OER rate measured under the established batch conditions (TiO2-700). Experiments operating under continuous mode revealed a remarkable efficiency for oxygen production, exceeding 12% of the apparent quantum efficiency (AQE) at 385 nm (UV-LED system) compared to the batch operation mode.

Diffraction study on bainite of Cu-Al alloy

1990 ◽  
Vol 48 (4) ◽  
pp. 1006-1007
Author(s):  
Delu Liu ◽  
T. Ko
Keyword(s):  
Diffraction Study ◽  
Parent Phase ◽  
Al Alloy ◽  
Alloy Sample ◽  
Bright Field Image ◽  
Hexagonal System ◽  
Iced Brine ◽  
Diffraction Patterns ◽  
Zone Pattern ◽  
Stacking Structure

Structure of bainite in Cu-Al and Cu-Zn-Al alloys has been reported as 3R, 9R or 18R long period stacking structure (LPS) by X-ray and electron diffraction studies. In the present work, a Cu-25.5 (at)% Al alloy sample was heated at 900°C for 2 h then isothermally held at 450°C for 60 s before quenching into iced brine. FIG.1 shows a TEM bright field image of bainite plates (marked B) grown from grain boundary. The parent phase ( with DO3 structure ) has transformed to martensite (marked M ) during cooling from 450° C to 0°C. Both bainite and martensite plates have dense striations inside.Careful diffraction study on a JEOL 2000FX TEM with accelerating voltage 200 KV revealed (FIG.2) that the diffraction patterns contai_ning the same zone axis [001] ( hexagonal index ) or [111]c ( cubic index ) are from a bainite plate with obtuse V-shape. They are indexed as [010], [140], [130], [120], [230], [340] and [110] zone pattern for hexagonal system respectively.

Highly efficient and selective photocatalytic CO2 to CO conversion in aqueous solution

2020 ◽  
Vol 56 (27) ◽  
pp. 3851-3854 ◽  
Author(s):  
Xiaomin Chai ◽  
Hai-Hua Huang ◽  
Huiping Liu ◽  
Zhuofeng Ke ◽  
Wen-Wen Yong ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Photocatalytic Performance ◽  
Aqueous Media ◽  
Highly Efficient ◽  
Co Conversion

A Co-based complex displayed the highest photocatalytic performance for CO2 to CO conversion in aqueous media.

Hydrothermal/Solvothermal Synthesis and Photocatalytic Performance of ZnS Microspheres

2016 ◽  
Vol 31 (5) ◽  
pp. 473 ◽  
Author(s):  
WU Xuan-Rong ◽  
YANG Qiao-Zhen ◽  
ZHAO Yong-Xiang ◽  
LU Yan-Luo
Keyword(s):  
Solvothermal Synthesis ◽  
Photocatalytic Performance

Tuning Transition Metal Carbides Activity by Surface Metal Alloying: Case Study on CO2 Capture and Activation

2018 ◽  
Author(s):  
Marti Lopez ◽  
Luke Broderick ◽  
John J Carey ◽  
Francesc Vines ◽  
Michael Nolan ◽  
...  
Keyword(s):  
Transition Metal ◽  
Co2 Capture ◽  
Density Functional ◽  
Deep Understanding ◽  
Metal Carbides ◽  
Transition Metal Carbides ◽  
Adsorption Sites ◽  
Surface Metal ◽  
A Minor

<div>CO2 is one of the main actors in the greenhouse effect and its removal from the atmosphere is becoming an urgent need. Thus, CO2 capture and storage (CCS) and CO2 capture and usage (CCU) technologies are intensively investigated as technologies to decrease the concentration</div><div>of atmospheric CO2. Both CCS and CCU require appropriate materials to adsorb/release and adsorb/activate CO2, respectively. Recently, it has been theoretically and experimentally shown that transition metal carbides (TMC) are able to capture, store, and activate CO2. To further improve the adsorption capacity of these materials, a deep understanding of the atomic level processes involved is essential. In the present work, we theoretically investigate the possible effects of surface metal doping of these TMCs by taking TiC as a textbook case and Cr, Hf, Mo, Nb, Ta, V, W, and Zr as dopants. Using periodic slab models with large</div><div>supercells and state-of-the-art density functional theory based calculations we show that CO2 adsorption is enhanced by doping with metals down a group but worsened along the d series. Adsorption sites, dispersion and coverage appear to play a minor, secondary constant effect. The dopant-induced adsorption enhancement is highly biased by the charge rearrangement at the surface. In all cases, CO2 activation is found but doping can shift the desorption temperature by up to 135 K.</div>

Study of the Photocatalytic Performance of Oxygen-deficient TiO2 Active in Visi-ble Light

2013 ◽  
Vol 27 (12) ◽  
pp. 1301-1305 ◽  
Author(s):  
Xiao-Xin CAO ◽  
Yi-Lin CHEN ◽  
Bi-Zhou LIN ◽  
Bi-Fen GAO
Keyword(s):  
Photocatalytic Performance
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