g-C.sub.3N.sub.4 has shown poor photocatalytic activity without co-catalyst. Studies on the chemical and physical properties of the g-C.sub.3N.sub.4 surface can help to understand the way how ...co-catalyst species interact with g-C.sub.3N.sub.4. To identify the role of the surface NH.sub.2 group in the formation of heterojunction photo-catalysts, g-C.sub.3N.sub.4/Melem was functionalized by different alkyl groups and characterized systematically by NMR, IR, UV-Vis, XPS and TEM. The surface alkyl groups affected the coordination of the Pt ion with the surface, and a significant photo-catalysis activity decrease was observed in turn. The results disclosed that the terminal NH.sub.2 played an important role in the formation of the co-catalyst heterojunctions and the surface catalysis active sites, and provided experimental evidence to understand the reaction mechanism. Graphic
Degradation of pharmaceuticals in water by TiOsub.2 photocatalysis often suffers from low efficiency due to low activity and mass transfer limitation. In this work, diclofenac removal in tap water ...was performed by photocatalysis on TiOsub.2 nanotube growth on Ti mesh substrate assisted by ozone (Osub.3), which was generated from a hole-arrayed boron-doped diamond (HABDD) film electrode. The vertically oriented TiOsub.2 nanotubes were used as the heterogeneous photocatalyst. The HABDD, as a self-standing diamond electrode, was designed and custom-made by MWCVD technology. The microstructures and crystalline of the TiOsub.2 nanotubes and HABDD were characterized by a scanning electronic micrograph (SEM) and X-ray diffraction (XRD). Unlike other ozone generation methods, direct generation of ozone in the flowing water was applied in the photocatalysis process, and its effect was discussed. The diclofenac removal performance of the electrochemical-photocatalytic system was studied depending on Osub.3 generation efficiency, flowing rate, and the initial diclofenac concentration. The enhanced degradation effect from Osub.3 molecules on TiOsub.2 photocatalysis was attributed to the larger active surface area, the increased photo-generated charge separation rate, and the contact area of Osub.3. The degradation efficiency in the combined electrochemical-photocatalytic TiOsub.2/Osub.3/UV system was higher than that of the Osub.3/UV and TiOsub.2/UV routes individually. Furthermore, a theoretical calculation was used to analyze the TiOsub.2/Osub.3 interface in aqueous media in terms of the final energy. This system created an almost in situ feeding channel of oxidants in the TiOsub.2 photocatalysis process, thus increasing photocatalytic efficiency. This synergetic system is promising in the treatment of pharmaceuticals in water.
Pharmaceuticals, especially amine-based pharmaceuticals, such as nizatidine and ranitidine, contaminate water and resist water treatment. Here, different amounts of graphene sheets are coupled with ...g-Csub.3Nsub.4 nanosheets (wt% ratio of 0.5, 1, 3 and 5 wt% of graphene) to verify the effect of surface plasmon resonance introduced to the g-Csub.3Nsub.4 material. The synthesized materials were systematically examined by advanced analytical techniques. The prepared photocatalysts were used for the degradation of amine-based pharmaceuticals (nizatidine and ranitidine). The results show that by introducing only 3 wt% graphene to g-Csub.3Nsub.4, the absorption ability in the visible and near-infrared regions dramatically enhanced. The absorption in the visible range was 50 times higher when compared to the pure sample. These absorption features suggest that the surfaces of the carbon nitride sheet are covered by the graphene nanosheet, which would effectively apply the LSPR properties for catalytic determinations. The enhancement in visible light absorption in the composite was confirmed by PL analysis, which showed greater inhibition of the electron-hole recombination process. The XRD showed a decrease in the (002) plan due to the presence of graphene, which prevents further stacking of carbon nitride layers. Accordingly, the Gr/g-Csub.3Nsub.4 composite samples exhibited an enhancement in the photocatalytic performance, specifically for the 5% Gr/g-Csub.3Nsub.4 sample, and close to 85% degradation was achieved within 20 min under solar irradiation. Therefore, applying the Gr/g-Csub.3Nsub.4 for the degradation of a pharmaceutical can be taken into consideration as an alternative method for the removal of such pollutants during the water treatment process. This enhancement can be attributed to surface plasmon resonance-induced photocatalysis in a 2D/2D graphene/g-Csub.3Nsub.4 heterostructure.
The S-scheme photocatalyst system has become increasingly popular in recent years for its ability to efficiently degrade various pollutants, including organic dyes, pesticides, and other harmful ...substances. This system uses two semiconductor photocatalysts with different bandgap energies, working together in a redox reaction to produce a highly reactive species capable of pollutant breakdown. Here, an S-scheme Agsub.2WOsub.4/Agsub.6Sisub.2Osub.7 p-n heterojunction nanocomposite was successfully developed by a coprecipitation method. By decomposing Rhodamine B (RhB) under visible-light irradiation, the photocatalytic activities of Agsub.6Sisub.2Osub.7/Agsub.2WOsub.4 showed enhanced photocatalytic degradation performance of organic dyes, especially at a 4% molar ratio of the Agsub.2WOsub.4-modified Agsub.6Sisub.2Osub.7 sample, whose degradation rate was 23.7 and 4.65 times those of Agsub.2WOsub.4 and Agsub.6Sisub.2Osub.7, respectively. The physical and chemical properties of the samples were determined by identifying the physical structure, chemical element composition, and optical responsiveness. The optimum composite amongst the prepared materials was AgSW-4, achieving the maximum RhB degradation efficiency of 97.5%, which was higher by 60% and 20% than its counterparts Agsub.6Sisub.2Osub.7 and Agsub.2WOsub.4, respectively. These results showed that in the nanocomposite structure, Agsub.6Sisub.2Osub.7 was a p-type semiconductor and Agsub.2WOsub.4 was an n-type semiconductor. Based on the analysis data, a comprehensive p-n heterojunction S-scheme process was proposed to demonstrate the enhanced photocatalytic performance of the Agsub.6Sisub.2Osub.7/Agsub.2WOsub.4 nanocomposite.
An error appeared in our paper entitled "The Keggin Structure: An Important Factor in Governing NH.sub.3-SCR Activity Over the V.sub.2O.sub.5-MoO.sub.3/TiO.sub.2Catalyst" published in Catalysis ...Letters. We used a wrong icon in Fig. 8. The black line should be "Cat-A-V" and the red line should be "Cat-B-V". The corrected Fig. 8 is shown below.
Our report is the first example describing the successful synthesis of magnetic Fesub.3Osub.4 nanoparticles (NPs), for which we used pulsed-laser induced photolysis (PLIP). Compared with the previous ...method of using pulsed-laser ablation of a target, or strong energy of pulsed-laser light to decompose precursors in generating a solvated-ion reaction, the PLIP method used here is dependent on hydrogen peroxide (Hsub.2Osub.2) to generate a hydrolysis reaction. Energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) were used to demonstrate the Fesub.3Osub.4 crystalline structure of the synthesized NPs. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images revealed that the average size of the NPs was about 20-50 nm. Regarding their magnetic characteristics, the synthesized NPs exhibited a saturation magnetization of 5.62 emu/g, remanence of 3.82 emu/g, and coercive force of 49.8 Oe. The photocatalytic experiments confirmed that the synthesized magnetic Fesub.3Osub.4 NPs have visible light-degradation effects based on their ability to photocatalytically degrade methylene blue (MB). The MB degradation efficiency was 60-80% under white-light exposure for 180 min. This study presents a new route for synthesizing magnetic Fesub.3Osub.4 NPs for their potential use in photocatalysis.
Revealing the charge transfer path is very important for studying the photocatalytic mechanism and improving photocatalytic performance. In this work, the charge transfer path turned by the ...piezoelectricity in Ag-BaTiOsub.3 nanofibers is discussed through degrading methyl orange. The piezo-photocatalytic degradation rate of Ag-BaTiOsub.3 is much higher than the photocatalysis of Ag-BaTiOsub.3 and piezo-photocatalysis of BaTiOsub.3, implying the coupling effect between Ag nanoparticle-induced localized surface plasmon resonance (LSPR), photoexcited electron-hole pairs, and deformation-induced piezoelectric field. With the distribution density of Ag nanoparticles doubling, the LSPR field increases by one order of magnitude. Combined with charge separation driven by the piezoelectric field, more electrons in BaTiOsub.3 nanofibers are excited by plasmon-induced resonance energy transfer to improve the photocatalytic property.
A novel magnetic Fe.sub.2O.sub.3/BiOI hybrid nanostructure was fabricated by combining electrospinning and successive ionic layer adsorption and reaction (SILAR) method. Hollow Fe.sub.2O.sub.3 ...nanofibers with internal diameter around 50 nm were produced by using electrospinning and calcinations of the as-spun fibers at 450 °C for 2 h. BiOI was deposited on the Fe.sub.2O.sub.3 nanofiber surface by SILAR method, and the BiOI quantity could be controlled by the growth cycles of SILAR. Similar synthetic procedure could also be used to prepare Fe.sub.2O.sub.3/BiOBr and Fe.sub.2O.sub.3/BiOCl hybrid nanostructures. The BiOI on the magnetic nanofiber surface is highly crystalline with lamellae morphology of around 16 nm in thickness from the X-ray diffraction and scanning electron microscopy detections. The obtained Fe.sub.2O.sub.3/BiOI hybrid nanostructures exhibit superior visible light catalytic performance toward decomposition of RhB. This new method, which can also be used to prepare other magnetic photocatalyst simply at low cost, is suitable for practical applications.
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