scholarly journals Visible Light Responsive Strontium Carbonate Catalyst Derived from Solvothermal Synthesis

Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1069
Author(s):  
Pornnaphat Wichannananon ◽  
Thawanrat Kobkeatthawin ◽  
Siwaporn Meejoo Smith
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Degradation Products ◽  
Reaction Pathway ◽  
Direct Injection ◽  
Radical Scavenging ◽  
Strontium Carbonate ◽  
Light Irradiation ◽  
Light Illumination ◽  
Strontium Hydroxide

A single crystalline phase of strontium carbonate (SrCO3) was successfully obtained from solvothermal treatments of hydrated strontium hydroxide in ethanol (EtOH) at 100 °C for 2 h, using specific Sr:EtOH mole ratios of 1:18 or 1:23. Other solvothermal treatment times (0.5, 1.0 and 3 h), temperatures (80 and 150 °C) and different Sr:EtOH mole ratios (1:13 and 1:27) led to formation of mixed phases of Sr-containing products, SrCO3 and Sr(OH)2 xH2O. The obtained products (denoted as 1:18 SrCO3 and 1:23 SrCO3), containing a single phase of SrCO3, were further characterized in comparison with commercial SrCO3, and each SrCO3 material was employed as a photocatalyst for the degradation of methylene blue (MB) in water under visible light irradiation. Only the 1:23 SrCO3 sample is visible light responsive (Eg = 2.62 eV), possibly due to the presence of ethanol in the structure, as detected by thermogravimetric analysis. On the other hand, the band gap of 1:18 SrCO3 and commercial SrCO3 are 4.63 and 3.25 eV, respectively, and both samples are UV responsive. The highest decolourisation efficiency of MB solutions was achieved using the 1:23 SrCO3 catalyst, likely due to its narrow bandgap. The variation in colour removal results in the dark and under visible light irradiation, with radical scavenging tests, suggests that the high decolourisation efficiency was mainly due to a generated hydroxyl-radical-related reaction pathway. Possible degradation products from MB oxidation under visible light illumination in the presence of SrCO3 are aromatic sulfonic acids, dimethylamine and phenol, as implied by MS direct injection measurements. Key findings from this work could give more insight into alternative synthesis routes to tailor the bandgap of SrCO3 materials and possible further development of cocatalysts and composites for environmental applications.

scholarly journals Enhanced Photocatalytic Degradation of Phenol Using Urchin-Like ZnO Microrod-Reduced Graphene Oxide Composite under Visible-Light Irradiation

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
S. Mary Margaret ◽  
Albin John P. Paul Winston ◽  
S. Muthupandi ◽  
P. Shobha ◽  
P. Sagayaraj
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Phenol Degradation ◽  
Hydrothermal Process ◽  
Light Irradiation ◽  
Light Illumination ◽  
Order Kinetic ◽  
Phenol Solution ◽  
Vis Spectroscopy

In this study, visible-light-driven ZnO microrod-rGO heterojunction composites were successfully synthesized via a facile and scalable hydrothermal process. The prepared photocatalyst heterojunction was examined using different techniques including XRD, SEM, FTIR, UV-Vis spectroscopy, and TGA to reveal their crystal phase, morphology, and other optical properties. The photocatalytic performance of the obtained ZnO-rGO composites was measured by the photodegradation of phenol under visible light illumination. The addition of graphene over the catalyst exhibited an enhanced photocatalytic activity for phenol degradation due to its high surface area and decreasing rate of electron-hole separation. Kinetic studies proved that the degradation of phenol process happened by following the pseudo-first-order kinetic model. The effective conditions for degradation of phenol using ZnO-rGO composite were 0.2 g L-1catalyst dose, pH -4, and initial concentration 20 ppm of phenol solution. Comparing with ZnO microrods, the heterojunction composite degraded the organic pollutants of phenol solution up to 84.2% of efficiency displaying the highest photocatalytic activity, whereas urchin-like ZnO catalyst exhibited much less photocatalytic activity for phenol degradation under visible light irradiation. This result envisages immense properties, showing a great potential industrial application for the removal of phenolic wastewater.

Pt-CdS/TiO2 nanotube catalyst for photocatalytic reduction of CO2 with water under visible light irradiation

2011 ◽  
Vol 1326 ◽  
Author(s):  
Jian Yuan ◽  
Chuanzhao Zhang ◽  
Caolong Li ◽  
Mingxia Chen ◽  
Wenfeng Shangguan
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Maximum Yield ◽  
Time Profile ◽  
Photocatalytic Reduction ◽  
Light Irradiation ◽  
Main Reaction ◽  
Light Illumination ◽  
Reaction Products ◽  
Reduction Of Co2

ABSTRACTTitanate nanotube (TNT) was prepared by alkaline hydrothermal method starting from TiO2 (P25), and then CdS-TNT was prepared for visible light harvesting by immersing TNT in Cd(CH3COO)2 and then (NH2)2CS aqueous solutions subsequently and heat treated at specialtemperature. After loading with Pt, photocatalytic reduction of gas phase CO2 with water vapor was carried out under UV-VIS and visible light irradiation. The results showed that the main reaction products were CH4, C2H4, C2H6 and H2, which were online characterized by gaschromatography when the flow rate of 5000 ppm CO2 is 0.35 ml/min. The hydrogenation process also realized under visible light illumination for Pt-CdS/TNT and producted 0.44 μmol/min CH4. The maximum yield of methane reached about 130 μmol/min when Pt-CdS/TNTwas irradiated with UV-Vis light. The time profile for production yield increased steadily with time up to about 6–7 h, then a decrease of the reaction rate occurred. It is suggested that thadsorption of intermediate products CO, O2 etc. on Pt and the oxidation of Pt might be the reasons for the photocatalytic reaction deterioration.

scholarly journals Thickness Dependent on Photocatalytic Activity of Hematite Thin Films

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Yen-Hua Chen ◽  
Kuo-Jui Tu
Keyword(s):  
Thin Films ◽  
Photocatalytic Activity ◽  
Film Thickness ◽  
Visible Light ◽  
Band Gap ◽  
Visible Light Irradiation ◽  
Hexagonal Structure ◽  
Light Irradiation ◽  
Light Illumination ◽  
Photocatalytic Ability

Hematite (Fe2O3) thin films with different thicknesses are fabricated by the rf magnetron sputtering deposition. The effects of film thicknesses on the photocatalytic activity of hematite films have been investigated. Hematite films possess a polycrystalline hexagonal structure, and the band gap decreases with an increase of film thickness. Moreover, all hematite films exhibit good photocatalytic ability under visible-light irradiation; the photocatalytic activity of hematite films increases with the increasing film thickness. This is because the hematite film with a thicker thickness has a rougher surface, providing more reaction sites for photocatalysis. Another reason is a lower band gap of a hematite film would generate more electron-hole pairs under visible-light illumination to enhance photocatalytic efficiency. Experimental data are well fitted with Langmuir-Hinshelwood kinetic model. The photocatalytic rate constant of hematite films ranges from 0.052 to 0.068 min-1. This suggests that the hematite film is a superior photocatalyst under visible-light irradiation.

A novel triphenylamine functionalized bithiazole–metal complex with C60 for photocatalytic hydrogen production under visible light irradiation

2015 ◽  
Vol 3 (12) ◽  
pp. 6258-6264 ◽  
Author(s):  
Jingpei Huo ◽  
Heping Zeng
Keyword(s):  
Hydrogen Production ◽  
Metal Complex ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Recyclable Catalyst ◽  
Light Irradiation ◽  
Light Illumination ◽  
Photocatalytic Hydrogen Production ◽  
Visible Light Illumination

Composite 6 (2.0 wt% C60) is an efficient and fully recyclable catalyst for photocatalytic H2 production (7.39 mmol h−1 g−1) under visible light illumination.

scholarly journals Photodegradation of naphthalene over Fe 3 O 4 under visible light irradiation

2019 ◽  
Vol 6 (1) ◽  
pp. 181779
Author(s):  
Jiawei Zhang ◽  
Shanshan Fan ◽  
Bin Lu ◽  
Qinghai Cai ◽  
Jingxiang Zhao ◽  
...  
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Degradation Products ◽  
Magnetic Measurement ◽  
Average Diameter ◽  
Degradation Pathway ◽  
Light Irradiation ◽  
Precipitation Method ◽  
Naoh Solution ◽  
Co Precipitation

Using FeCl 3 and FeSO 4 as precursors, Fe 3 O 4 were prepared by co-precipitation method via FeCl 3 and FeSO 4 aqueous solutions successively added to NaOH solution. The sample was proved by X-ray powder diffraction, transmission electron microscope, ultraviolet–visible spectrophotometry and magnetic measurement. The results showed that the prepared Fe 3 O 4 material was composed of an average diameter of about 15 nm particles and nano rods with well-crystallized magnetite and stronger superparamagnetic, getting a saturation magnetization of 49.5 emu g −1 . This Fe 3 O 4 material was found to be an effective catalyst for photodegradation of naphthalene with or without H 2 O 2 under visible light irradiation, getting 81.1% and 74.3% degradation rate in these two cases, respectively. The degradation pathway in the absence and presence of H 2 O 2 was analysed via measurement of the distribution of degradation products by GC-MS and adsorption of reactants on the surface of the catalyst by in situ DRIFTS spectra.

Selective aerobic oxidation of alkyl aromatics on Bi2MoO6 nanoplates decorated with Pt nanoparticles under visible light irradiation

2018 ◽  
Vol 54 (86) ◽  
pp. 12194-12197 ◽  
Author(s):  
Bao Zhang ◽  
Xiaojing Yang ◽  
Jun Li ◽  
Gang Cheng
Keyword(s):  
Visible Light ◽  
Selective Oxidation ◽  
Visible Light Irradiation ◽  
Aerobic Oxidation ◽  
Pt Nanoparticles ◽  
Light Irradiation ◽  
Light Illumination ◽  
Visible Light Illumination ◽  
Selective Aerobic Oxidation

Pt/Bi2MoO6 nanoplates are efficient photocatalysts for the selective oxidation of saturated C–H bonds in alkyl aromatics under visible light illumination using O2 as an oxidant.

Photocatalytic Activity of Neodymium Ion Doped TiO2 for 2-Mercaptobenzothiazole Degradation under Visible Light Irradiation

2005 ◽  
Vol 2 (2) ◽  
pp. 130 ◽  
Author(s):  
Fang Bai Li ◽  
Xiang Zhong Li ◽  
Kok Wai Cheah
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Light Irradiation ◽  
Optimal Dosage ◽  
Light Illumination ◽  
Significant Activity ◽  
Analytical Results ◽  
Neodymium Ion

Environmental Context. Conventional titanium dioxide catalysts can assist oxidation reactions upon ultraviolet light irradiation. Such photocatalysts are used to degrade organic pollutants in water to less harmful inorganic materials. By modifying the catalyst with luminescent lanthanide ions, the pollutant degradation reaction takes place upon visible light illumination. 2-Mercaptobenzothiazole, a poorly biodegradable and malodourous pollutant used both as a corrosion inhibitor and antifungal agent, is shown to be efficiently mineralized to carbon dioxide, water, ammonium, nitrate, and sulfate with this new catalyst. Abstract. A series of neodymium ion-doped titanium dioxide (Nd3+-TiO2) catalysts were prepared by means of a sol–gel method. The physical and chemical properties of the catalysts were characterized by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) N2 sorbtion method, UV-visible diffusive reflective spectroscopy (DRS), and photoluminescence (PL) analyses. The adsorption behaviour and photocatalytic activity of Nd3+-TiO2 under visible light irradiation were evaluated for aqueous 2-mercaptobenzothiazole (MBT) solution. The analytical results of XRD and BET demonstrate that the neodymium ion doping could reduce the crystallite size and increase the specific surface area of TiO2 catalysts. The analytical results of DRS show that Nd3+ doping did not shift the main absorption band edge significantly, but some new absorption peaks attributable to 4f internal electron transition existed in the visible region. It was further confirmed that significant PL emission occurred in the visible range of 350–700 nm, attributable to the electron transfer between Nd3+ and TiO2 owing to introduction of a Nd 4f level. The experimental results of adsorption isotherm tests demonstrate that both the saturated adsorption amount (Γmax) and adsorption equilibrium constant (Ka) of Nd3+-TiO2 catalysts increased significantly with the increased Nd3+ dosage. Furthermore, the Nd3+-TiO2 catalysts demonstrated significant activity towards photocatalytic degradation of MBT in aqueous solution under visible light irradiation, whereas the TiO2 catalyst did not. An optimal dosage of Nd3+ doping was found to be 0.7%. We propose that the introduction of the Nd 4f level plays a crucial role in visible photosensitization and enhancement of the electron–hole separation.

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