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1.
A facile, one-step synthesis of graphene-oxide (GO)/Ag 3PO 4 was prepared. The as-prepared samples were characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS) and fourier transformed infrared (FT-IR) spectroscopy. The SEM image indicated that Ag 3PO 4 particles were mainly distributed on the surface of GO sheets uniformly. DRS analysis revealed that the samples had good visible light response. The photocatalytic activity of the composites was evaluated by the degradation of Rhodamine B (RhB) and Bisphenol A (BPA). The results indicated that the photocatalytic performance of GO/Ag 3PO 4 was greatly enhanced after introduction of GO. The photocatalytic degradation efficiency of colorless chemical pollutants (BPA) over GO/Ag 3PO 4 was higher than that of Ag 3PO 4, and the possible degradation path was proposed by liquid chromatography mass spectrometry (LC-MS) analysis. Moreover, the photocatalytic stability was discussed by XRD and FT-IR spectroscopy analysis. Based on the experimental results, a possible visible-light photocatalytic degradation mechanism was also discussed. 相似文献
2.
In this work, a ternary composite photocatalyst of graphitic carbon nitride ( g-C 3N 4), graphene oxide (GO), and Ag 3PO 4 was prepared through a simple precipitation route, in which Ag 3PO 4 nanoparticles covered or wrapped with GO sheets are supported on g-C 3N 4 sheets. The composite photocatalyst displays enhanced absorption in the visible region, and exhibited superior photocatalytic activity compared with single-component or binary composite photocatalysts in the photocatalytic decomposition of Rhodamine B. The enhancement of photocatalytic activity could be attributed to the synergistic effect among them. The ternary composite also exhibited enhanced stability, but further efforts should be made to make it more stable. 相似文献
3.
We report a novel, green, scalable technique to synthesize binder-free, high-purity conductive composite comprising activated carbon (AC), manganese dioxide nanorods (MnO 2), and reduced graphene oxide sheets (rGO) for flexible supercapacitors with outstanding electrochemical performance. UV pulsed laser irradiation of GO-based composite dispersion (AC/GO or MnO 2@AC/GO) in ethanol aqueous medium was used to induce a photocatalytic reduction of GO and simultaneous anchor AC particles or AC loaded MnO 2 nanorods (MnO 2@AC) on the reduced GO sheets (rGO) at room temperature and atmospheric pressure. rGO sheets serve as a large surface area, conductive binder to enhance the ion adsorption, electrical conductivity, and mechanical flexibility of supercapacitor electrodes. This laser-induced photocatalytic reduction method was used to prepare two different rGO-based colloidal composites AC/rGO (CG) and MnO 2@AC/rGO (MCG). The prepared rGO-based colloidal composites were used to fabricate symmetric supercapacitors (CG//CG and MCG//MCG) and asymmetric supercapacitors (MCG//CG) in which MCG is the positive electrode and CG is the negative one. All prepared rGO-based supercapacitors demonstrated significant improvement in their electrochemical performance compared with rGO-free AC based supercapacitors. The enhancement in the electrochemical properties of rGO-based supercapacitors could be attributed to the intrinsic characteristics of rGO, such as high surface area, excellent electrical conductivity, and super mechanical flexibility. Our approach is a one-step, scalable, cost-effective synthesis technique to produce all binder-free AC/rGO based composites for flexible energy-storage devices. 相似文献
4.
A novel photodegradable polystyrene-grafted-TiO 2 (PS- g-TiO 2) nanocomposite was prepared by embedding the grafted-TiO 2 into the commercial polystyrene. Solid-phase photocatalytic degradation of the PS- g-TiO 2 nanocomposite was carried out in ambient air at room temperature under ultraviolet lamp and/or sunlight irradiation. The properties of composite film were compared with those of the pure PS film by methods such as weight loss measurement, scanning electron microscope (SEM), gel permeation chromatogram (GPC), X-ray photoelectron spectroscopy (XPS), FT-IR spectroscopy, and UV-vis spectroscopy. The results show that the photo-induced degradation of PS- g-TiO 2 composite film is significantly higher than that of pure PS film. The weight loss of composite film reached 31.9%, average molecular weight ( Mw) of composite film decreased by 53.1%, and the number average molecular weight ( Mn) decreased by 73.2% after 396 h of UV-light irradiation. FT-IR analysis and weight loss indicated that the benzene rings in PS-matrix of composite film were cleaved during UV-light irradiation. The photocatalytic degradation mechanism of the films is briefly discussed. 相似文献
5.
Ag 2O-decorated flower-like ZnO composites were fabricated through a chemical precipitation process. X-ray diffraction analysis confirms the co-existence of cubic Ag 2O and wurtzite ZnO phases. Scanning electron microscopy images reveal Ag 2O nanoparticles located on the rough surface of ZnO flowers. The photocatalytic activities of the composites with various mole ratios were evaluated by the degradation of methyl orange (MO) under ultraviolet irradiation, which confirms that the composite shows superior activity to that of pure ZnO and Ag 2O. The improvement can be ascribed to the deposited Ag 2O forming the p-n junction at the interface of ZnO and Ag 2O, resulting in the transfer of photocarriers and suppressing the electron–hole recombination rate. 相似文献
6.
FeTiO 3/TiO 2, a new heterojunction-type photocatalyst working at visible light, was prepared by a simple sol–gel method. Not only did FeTiO 3/TiO 2 exhibit greatly enhanced photocatalytic activity in decomposing 2-propanol in gas phase and 4-chlorophenol in aqueous solution, but also it induced efficient mineralization of 2-propanol under visible light irradiation ( λ ≥ 420 nm). Furthermore, it showed a good photochemical stability in repeated photocatalytic applications. FeTiO 3 showed a profound absorption over the entire visible range, and its valence band (VB) position is close to that of TiO 2. The unusually high photocatalytic efficiency of the FeTiO 3/TiO 2 composite was therefore deduced to be caused by hole transfer between the VB of FeTiO 3 and TiO 2. 相似文献
7.
Photocatalytic reduction of carbon dioxide (CO 2) into hydrocarbon fuels such as methane is an attractive strategy for simultaneously harvesting solar energy and capturing this major greenhouse gas. Incessant research interest has been devoted to preparing graphene-based semiconductor nanocomposites as photocatalysts for a variety of applications. In this work, reduced graphene oxide (rGO)-TiO 2 hybrid nanocrystals were fabricated through a novel and simple solvothermal synthetic route. Anatase TiO 2 particles with an average diameter of 12 nm were uniformly dispersed on the rGO sheet. Slow hydrolysis reaction was successfully attained through the use of ethylene glycol and acetic acid mixed solvents coupled with an additional cooling step. The prepared rGO-TiO 2 nanocomposites exhibited superior photocatalytic activity (0.135 μmol g cat−1 h −1) in the reduction of CO 2 over graphite oxide and pure anatase. The intimate contact between TiO 2 and rGO was proposed to accelerate the transfer of photogenerated electrons on TiO 2 to rGO, leading to an effective charge anti-recombination and thus enhancing the photocatalytic activity. Furthermore, our photocatalysts were found to be active even under the irradiation of low-power energy-saving light bulbs, which renders the entire process economically and practically feasible. 相似文献
8.
A visible light active binary SnO 2-TiO 2 composite was successfully prepared by a sol-gel method and deposited on Ti sheet as a photoanode to degrade orange II dye. Titanium and SnO 2 can promote the development of rutile phase of TiO 2 and inhibit the formation of anatase phase of TiO 2. Formation of SnO 2 crystalline is insignificant even when the calcination temperature increases to 700 °C. Heterogenized interface between SnO 2 and TiO 2 inhibits growth of TiO 2 linkage and leads to the particle-filled surface morphology of SnO 2-containing films. The carbonaceous, Ti-O-C bonds and Ti 3+ species are likely to account for the photoabsorption and photoelectrocatalytic (PEC) activity under visible light illumination. The electrode with 30% SnO 2 exhibits higher photocurrent when compared with those in the region of 0-50%. The 600 °C-calcined SnO 2-TiO 2 electrode indicates higher activity when compared with those at 400, 500, 700 and 800 °C. PEC degradation of orange II follows the Langmuir-Hinshelwood model and takes place much effectively in a solution of pH 3.0 than those in pH 7.0 and pH 11.0. 相似文献
9.
Heterogeneous Ag/Ag 3PO 4/BiPO 4 photocatalyst was synthesized by a one-step low temperature chemical bath method and exhibited better photocatalytic activity and better stability than those of individual Ag 3PO 4 or BiPO 4 nanoparticles for photodegradation of organic compounds (Rhodamine B) in the absence of electron accepters under visible light ( λ>420 nm). The enhanced photocatalytic performance is mainly ascribed to the strong visible-light absorption originating from high efficient separations of photogenerated electron–hole pairs through Ag 3PO 4/BiPO 4 and Ag/Ag 3PO 4 heterostructures. 相似文献
10.
V 2O 5 was loaded on the surface of C-doped TiO 2 (C-TiO 2) by incipient wetness impregnation in order to enhance the visible light photocatalytic performance. The physicochemical properties of the C-TiO 2/V 2O 5 composite were characterized by XRD, Raman, TEM, XPS, UV–vis diffuse reflectance spectra, and PL in detail. The result indicated that a heterojunction between C-TiO 2 and V 2O 5 was formed and the separation of excited electron–hole pairs on C-TiO 2/V 2O 5 is greatly promoted. Thus, this composite photocatalyst exhibited enhanced visible light photocatalytic activity in degradation of gas-phase toluene compared with the pristine C-TiO 2. 相似文献
11.
Shape-controlled silver nanoparticles (Ag NPs) were prepared in a well-dispersed mode on the active imprinting sites of chitosan-TiO 2 adsorbent (CTA) by means of bioaffinity adsorption and TiO 2 photocatalysis. Nontoxic hydrogen peroxide (H 2O 2) was used as a suitable etching reagent in our production of shape-controlled Ag NPs, since it could regulate the TiO 2 photocatalysis and accelerate the generation of O 2. With the same amount of H 2O 2 addition, silver nanocubes, nanospheres and truncated triangular nanoplates were individually obtained on the surface of CTA under UV irradiation by facilely adjusting the initial Ag + concentration. The FE-SEM, XRD and UV-visible characterizations confirmed single crystal Ag NPs with different shapes loaded on CTA. The mechanism for the formation of shape-controlled Ag NPs was discussed based on a photocatalytic reaction system. As an example of applications of the Ag NPs, we tested the biocidal properties, and silver nanocubes exhibited the highest antibacterial activity. Our research provided a simple synthesis for shape-regulated Ag NPs steadily loaded on CTA. It might moreover be a guide in preparing metal nanocrystals monodispersely immobilized on chemical substrates. 相似文献
12.
The TiO 2 pillared fluoromica powder was kneaded with polylactic acid resin. The composite showed high photocatalytic activity for degradation of acetaldehyde and toluene gas, especially at the range of 1–3 wt.% pillared mica powder, and this photocatalytic activity was higher than that of resins containing even higher amounts of commercial TiO 2 (P-25, Degussa). The composite test pieces of pillared mica showed smaller photocatalytic deterioration than the samples with P-25 powder in out-door weathering tests. Thus, the TiO 2 pillared clay resin composite shows excellent prevention of photocatalytic deterioration and high photocatalytic activity in comparison with P-25. 相似文献
13.
In this study, we demonstrate the fabrication of multifunctional composite polyurethane (PU) membrane from a sol gel system containing TiO 2 and fly ash (FA) nanoparticles (NPs). The adsorptive property of FA and photocatalytic property of TiO 2 can introduce different functionalities on PU mat for water purification. Different types of PU nanofiber mats were prepared by varying the composition of NPs in blend solution. FE-SEM, TEM, TGA, XRD, UV–visible spectra, and water contact angle measurement confirmed the incorporation of FA and TiO 2 NPs on/into PU nanofibrous mat. The influence of NPs on PU membrane was evaluated from the adsorption of heavy metals (Hg, Pb), removal of dyes (methylene blue), antibacterial activity, and water flux. The improvement of all these activities is attributed to the adsorptive property of FA and photocatalytic/hydrophilic property of TiO 2 NPs. Therefore, as-synthesized composite membrane can be utilized as an economically friendly filter media for water purification. 相似文献
14.
ZrO 2 prepared by the precipitation method of zirconium oxychloride with various hydrolyzing agents was studied for photocatalytic
water splitting reaction under UV light irradiation. The crystal structure as well surface properties were varied with the
hydrolyzing agent of KOH, NH 4OH, and NH 2CONH 2. Especially, the surface area of the prepared ZrO 2 calcined at the same temperature of 750 °C for 6 h was dependent highly on the hydrolyzing agent, and thus the highest photocatalytic
activity was obtained for ZrO 2 with the highest surface area when KOH was used as a hydrolyzing agent, In the presence of Na 2CO 3, the photocatalytic activity of ZrO 2 increased by 2–3 fold, which was ascribed to the physically adsorbed carbonate species on the ZrO 2 surface.
This paper is dedicated to Professor Hyun-Ku Rhee on the occasion of his retirement from Seoul National University. 相似文献
15.
The complete photocatalytic oxidation of C 2H 4 with O 2 into CO 2 and H 2O has been achieved on ultrafine powdered TiO 2 photocatalysts and the addition of H 2O was found to enhance the reaction. The photocatalytic reaction has been studied by IR, ESR, and analysis of the reaction
products. UV irradiation of the photocatalysts at 275 K led to the photocatalytic oxidation of C 2H 4 with O 2 into CO 2, CO, and H 2O. The large surface area of the photocatalyst is one of the most important factors in achieving a high efficiency in the
photocatalytic oxidation of C 2H 4. The photoformed OH species as well as O
2
−
and O
3
−
anion radicals play a significant role as a key active species in the complete photocatalytic oxidation of C 2H 4 with O 2 into CO 2 and H 2O. Interestingly, small amount of Pt addition to the TiO 2 photocatalyst increased the amount of selective formation of CO 2 which was the oxidation product of C 2H 4 and O 2. 相似文献
16.
The production of fuels with a low sulfur content has been paid significant attention in the manufacturing of petroleum refining due to the progressively severe environmental legislations obliged by governments worldwide. In this paper, for the first time, two dimensional mesoporous Ag 2O/ZrO 2 heterostructures were synthesized by a facile approach for thiophene photocatalytic oxidative desulfurization under visible-light exposure at room temperature. The Ag 2O/ZrO 2 heterostructures significantly enhanced the photocatalytic desulfurization of thiophene obeyed the pseudo-first-order model compared to pristine ZrO 2 NPs. In particular, 1.5%Ag 2O/ZrO 2 photocatalyst exhibited better photocatalytic performance and the correspondent rate constant of 0.0235 min ?1, which was promoted 5.35 times than that of pristine ZrO 2 NPs (0.0044 min ?1). The desulfurization rate of thiophene over 1.5% Ag 2O/ZrO 2 heterostructure was enhanced 3.7 times larger than that of pristine ZrO 2 NPs. The thiophene was photocatalytically oxidized to CO 2 and SO 3. The photocatalytic performance of Ag 2O/ZrO 2 could be enhanced because of its synergetic effects, the intense visible-light harvest, rapid mobility of the thiophene to the active sites, a lower light scattering effect, and a large ?OH radical contents formed. Moreover, the Ag 2O/ZrO 2 heterostructures revealed excellent stability toward the photocatalytic oxidative desulfurization of thiophene. A possible charge separation mechanism over mesoporous Ag 2O/ZrO 2 heterostructures was proposed. 相似文献
17.
Self-organized V-N co-doped TiO 2 nanotube arrays (TNAs) with various doping amount were synthesized by anodizing in association with hydrothermal treatment. Impacts of V-N co-doping on the morphologies, phase structures, and photoelectrochemical properties of the TNAs films were thoroughly investigated. The co-doped TiO 2 photocatalysts show remarkably enhanced photocatalytic activity for the CO 2 photoreduction to methane under ultraviolet illumination. The mechanism of the enhanced photocatalytic activity is discussed in detail. 相似文献
18.
This work explores the effect of ternary nanostructure for the enhanced photocatalytic degradation of pollutants and dyes. One-pot solvothermal-assisted approach was used for producing nanosized Pt@TiO2 hybrid nanoparticles (NPs) decorated on reduced graphene oxide (rGO) layers. The microstructure, morphology, chemical composition, and optical absorption of the designed photocatalyst was successfully characterized (using XRD, TEM, Raman, UV–visible absorption spectra, and XPS techniques). The ternary Pt@TiO2-rGO photocatalyst consist of monodisperse quasi-spherical Pt@TiO2 NPs with an average size of 11 nm deposited on the rGO nanosheets. Furthermore, Pt@TiO2-rGO was further investigated for the photodegradation of pesticide and dyes under UV and visible light. The ternary Pt@TiO2-rGO photocatalyst proved a significant improvement on the photodecomposition of pollutants compared to hybrid Pt@TiO2. The Pt@TiO2-rGO photocatalyst was found to show seven- and threefold increase in the photocatalytic activity compared to TiO2 and Pt@TiO2 NPs, respectively which resulted from the high surface area of rGO and as well as the strong Pt/TiO2/rGO interactions which ensured excellent properties of charge separation. On the other hand, the ternary photocatalyst exhibited very good recycle and reuse capacity up to five cycles. 相似文献
19.
In this study, Ag 2CO 3/SnFe 2O 4 (Ag 2CO 3/SFO) photocatalyst was prepared by a simple hydrothermal-ultrasonic method for the efficient degradation of ciprofloxacin and phenol. The SFO nanoparticles were attached on the surface of Ag 2CO 3 rods synthesized by a low-temperature precipitation method, resulting a unique 1D/0D morphology, which increased the number of active sites. Due to introduction of magnetic SFO, Ag 2CO 3/SFO exhibited excellent magnetic recovery performance. When the mass fraction of SFO was 5%, the degradation efficiency of composite photocatalyst was the highest, the degradation rate for ciprofloxacin was 6.5 and 1.5 times higher than pure SFO and Ag 2CO 3, respectively. The improved photoactivity of Ag 2CO 3/SFO should be attributed to the construction of heterojunction with tight interface, which boosts the separation and transfer of photoinduced electron and hole pairs. On the basis of experimental results, a possible Z-scheme photocatalytic mechanism was discussed. Additionally, the excellent photostability of Ag 2CO 3/SFO was proved by a cycle experiment. 相似文献
20.
A series of V 2O 5-TiO 2 aerogel catalysts were prepared by the sol-gel method with subsequent supercritical drying with CO 2. The main variables in the sol-gel method were the amounts of V 2O 5 and when the vanadium precursor was introduced. V 2O 5-TiO 2 xerogel and V 2O 5/TiO 2 (P-25) were also prepared for comparison. The V 2O 5-TiO 2 aerogel catalysts showed much higher surface areas and total pore volumes than V 2O 5-TiO 2 xerogel and impregnated V 2O 5/TiO 2 (P-25) catalysts. The catalysts were characterized by N 2 physisorption, X-ray diffraction (XRD), FT-Raman spectroscopy, temperature-programmed reduction with H 2 (H 2-TPR), and temperature-programmed desorption of ammonia (NH 3-TPD). The selective catalytic reduction of NOx with ammonia in the presence of excess O 2 was studied over these catalysts. Among various V 2O 5-TiO 2 catalysts, V 2O 5 supported on aerogel TiO 2 showed a wide temperature window exhibiting high NOx conversions. This superior catalytic activity is closely related to
the large amounts of strong acidic sites as well as the surface vanadium species with characteristics such as easy reducibility
and monomeric and polymeric vanadia surface species.
This work was presented at the 7
th
Korea-China Workshop on Clean Energy Technology held at Taiyuan, Shanxi, China, June 26–28, 2008. 相似文献
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