Search

The development of photocatalysts for organic degradation is a hot research topic. In this study, CdZnS was selected as the carrier, and ZIF-8 was combined with it to explore the photocatalytic performance of the composite. In addition, the compound material, CdZnS@ZIF-8, was used as a photocatalyst for the decomposition of methylene blue dye, and the performance of pure CdZnS and pure ZIF-8 was compared. The photocatalytic efficiency of CdZnS@ZIF-8 was significantly higher than that of the other two. In the experimental reaction, the amount of catalyst was 0.04 g, the pH value was 7, the initial concentration of methylene blue aqueous solution was 20 mg/L, and the degradation of methylene blue in 50 mL aqueous solution could reach 99.5% under visible light irradiation for 90 min, showing excellent photocatalytic efficiency in the visible light range. It demonstrated excellent photocatalytic function in the visible light region, and the electron transfer phenomenon at the interface occurred in the het-junction and the separation of the photo-generating electron–hole as an electron acceptor of ZIF-8 further promoted the photocatalytic effect. [ABSTRACT FROM AUTHOR]

The problem of industrial dyes depollution has pushed the scientific research community to identify novel photocatalysts with high performance. Herein, new photocatalysts composed of BaTiO3, BaTi0.96Cu0.04O3, BaTi0.96Cu0.02V0.02O3 and BaTi0.96Cu0.02Nb0.02O3 powders were prepared by solid-state reaction. The structural analysis of the samples confirmed the formation of the BaTiO3 structure. The splitting of (002) and (200) planes verified the formation of the tetragonal phase. The XRD peaks shifted, and the unit cell volume expansion verified the substitution of the Ti4+ site by Cu2+, V4+ and Nb5+ ions. The morphological measurements showed that the addition of (Cu, V) and (Cu, Nb) ions changes the particles' morphology of BaTiO3, reducing its grains size. After the incorporation of (Cu, V) and (Cu, Nb) ions, the band gap of BaTiO3 was reduced from 3.2 to 2.84 and 2.72 eV, respectively. The modification of BaTiO3 by (Cu, Nb) ions induced superior photocatalytic properties for methyl green and methyl orange with degradation efficiencies of 97% and 94% during 60 and 90 min under sunlight irradiation, respectively. The total organic carbon results indicated that the BaTi0.96Cu0.02Nb0.02O3 catalyst has a high mineralization efficiency. In addition, it possesses a high stability during three cycles. The high photodegradation efficiency of Bi0.96La0.02Gd0.02FeO3 was related to the wide-ranging visible light absorption. [ABSTRACT FROM AUTHOR]

Photocatalytic dye degradation is an energy-saving, environmentally friendly and sustainable way of managing potentially toxic wastewater from the textile industry. PbTiO3 was prepared using a solid-state reaction method, and an optimal ratio of PbTiO3/TiO2/g-C3N4 photocatalyst was synthesized using the sol-gel method to test its ability to decompose organic dyes. Methylene blue (MB) was selected as a target dye to test the photocatalytic effects. SEM results showed that the synthesis of a PbTiO3/TiO2/g-C3N4 photocatalyst yielded a unique nano structure with many surface pores. UV-Vis analysis demonstrated that the novel composite photocatalyst had higher visible light absorption, and a reduced energy gap. Experimental results showed that of the samples tested, PTO/TO/CN 1.0 showed the best photocatalytic effect on the removal of MB. Under visible light, the removal rate of MB by PTO/TO/CN 1.0 was up to 98.79%. The novel PTO/TO/CN 1.0 photocatalyst exhibited relatively high MB adsorption and had a high photocatalytic ability. [ABSTRACT FROM AUTHOR]

Unique nonlinear optical properties for converting low-energy incident light into high-energy radiation enable up-conversion materials to be employed in photocatalytic systems. An efficient near-infrared (NIR) response photocatalyst was successfully fabricated through a facile two-step method to load BiOBr on the Nd3+, Er3+@NaYF4 (NE@NYF) up-conversion material. The NE@NYF can transform NIR into visible and UV light and promote charge–energy transfer in the semiconductor. Consequently, the as-obtained photocatalysts exhibit excellent photodegradation performance for rhodamine B dye (RhB) and tetracycline (TC) organic pollutants. About 98.9% of the RhB was decomposed within 60 min with the 20% NE@NYF-B sample, outperforming the pristine BiOBr (61.9%). In addition, the 20% NE@NYF-B composite could decompose approximately 72.7% of the organic carbon during a 10 h reaction, which was almost two-fold more than that of BiOBr. Meanwhile, a possible charge transfer mechanism is proposed based on the recombination of electron–hole pairs and reactive oxygen species. This work provides a rational hybrid structure photocatalyst for improving photocatalytic performance in the broadband spectrum and provides a new strategy for NIR light utilization. [ABSTRACT FROM AUTHOR]

Metal ion doping is the most widely used means to improve the photocatalytic performance of semiconductor materials, which can adjust the band gap, broaden the range of optical response and construct impurity levels. The high efficiency modified NaTaO3 perovskite catalyst with good structural and catalytic properties was synthesized by a simple hydrothermal reaction method. A variety of analysis and testing techniques, such as XRD, SEM, DRS, XPS and EPR, were used to analyze the structure properties of the prepared materials. The results show that the influence mechanism of different metal introduction on the structure and properties of the NaTaO3 perovskite was different. Metal doping promoted the bond angle of Ta-O-Ta close to 180°, which restrains the recombination of the photogenerated electron-holes in the crystal. As Ce is introduced into the perovskite, the CeO2 forms and agglomerates around the perovskite, which improves the electron transport performance. With the narrower band gap, the Ce-modified perovskite shows that the degradation rate of ARS is 84% after 180 min of photoreaction. The species of h+, O2− and ·OH play different roles in improving the performance of the photocatalytic degradation process. [ABSTRACT FROM AUTHOR]

In this work, photocatalytic materials constituted by Cr-doped TiO2 (Cr-TiO2) decorated with noble metals show high effectiveness in the mineralization of Acid Orange 7 (AO7) and in the disinfection of real river water. The materials were firstly obtained by sol-gel method to get Cr-TiO2 that was subsequently modified by photochemical deposition of Ag or Pd nanoparticles (Ag/Cr-TiO2, Pd/Cr-TiO2). Chemical-physical characterization results evidenced that the noble metals were homogeneously distributed on the Cr-TiO2 surface. By using Pd(0.25%)/Cr-TiO2, the AO7 discoloration efficiency was about 91.4% after only 60 min of visible irradiation, which can be due to the lowest band gap of this material. Moreover, nitrates, chlorides, total hardness, and coliform bacteria content significantly decreased after the treatment of real river water samples (that is contaminated by industrial and domestic effluents) under UV and visible light irradiation in the presence of TiCrOx decorated with noble metals. One hundred percent of elimination rate for E. coli, total coliforms, and other enterobacteriaceae (without regrowth) was achieved by using Ag/Cr-TiO2 as photocatalyst. [ABSTRACT FROM AUTHOR]

In this study, the Mg2+-doped anatase TiO2 phase was synthesized via the solvothermal method by changing the ratio of deionized water and absolute ethanol Vwater/Vethanol). This enhances the bleaching efficiency under visible light. The crystal structure, morphology, and photocatalytic properties of Mg-doped TiO2 were characterized by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, N2 adsorption-desorption, UV-Vis spectroscopy analysis, etc. Results showed that the photocatalytic activity of the Mg2+-doped TiO2 sample was effectively improved, and the morphology, specific surface area, and porosity of TiO2 could be controlled by Vwater/Vethanol. Compared with the Mg-undoped TiO2 sample, Mg-doped TiO2 samples have higher photocatalytic properties due to pure anatase phase formation. The Mg-doped TiO2 sample was synthesized at Vwater/Vethanol of 12.5:2.5, which has the highest bleaching rate of 99.5% for the rhodamine B dye during 80 min under visible light. Adding Mg2+-doped TiO2 into the phase-separated glaze is an essential factor for enhancing the self-cleaning capability. The glaze samples fired at 1180 °C achieved a water contact angle of 5.623° at room temperature and had high stain resistance (the blot floats as a whole after meeting the water). [ABSTRACT FROM AUTHOR]

MIL-101(Cr)@TiO2 core-shell composite material was synthesized via the hydrothermal method, where MIL-101(Cr) served as the core and TiO2 acted as the shell. SEM results revealed that the metal-organic framework core effectively prevented the aggregation of TiO2 nanoparticles and facilitated their dispersion. Characterization techniques such as XRD, XPS, and TGA were utilized to confirm the successful loading of TiO2 onto MIL-101(Cr) and its excellent thermal stability. MIL-101(Cr)@TiO2 was employed in photocatalytic degradation of dye pollutants and vehicle exhaust, and the potential degradation mechanisms were investigated in detail. The results showed that MIL-101(Cr)@TiO2 exhibited excellent photocatalytic degradation performance towards dye pollutants, with degradation efficiencies of 91.7% and 67.8% achieved for MB and RhB, respectively, under visible light irradiation for 90 min. Furthermore, the photocatalytic degradation of automobile exhaust revealed that the MIL-101(Cr)@TiO2 composite material also exhibited degradation effects on NOx, CO, and HC. The degradation efficiency for NO reached 24.2%, indicating its broader applicability. [ABSTRACT FROM AUTHOR]

To simulate natural photosynthesis, scientists have developed an artificial Z-scheme system that splits water into hydrogen and oxygen using two different semiconductors. Researchers are striving to improve the performance of Z-scheme systems by improving light absorption, developing redox couples with high stability, and finding new cocatalysts. Here, we report the synthesis and utilization of LaFeO3/g-C3N4 as a Z-scheme system for water reduction to produce hydrogen and organic dye degradation under visible light irradiation. The as-fabricated photocatalyst revealed exceptional activity for H2 production (i.e., 351 µmol h−1g−1), which is 14.6 times higher compared to that of the single-component g-C3N4 (i.e., 24 µmol h−1g−1). In addition, the composite photocatalyst degraded 87% of Methylene Blue (MB) and 94% of Rhodamine B (RhB) in 2 h. Various experimental analyses confirmed that the exceptional performance of the LaFeO3/g-C3N4 Z-scheme catalyst is due to remarkably enhanced charge carrier separation and improved light absorption. The development of this highly effective Z-scheme heterostructure photocatalyst will pave the way for the sustainable development of newly designed Z-scheme scheme systems that will tackle energy and environmental crises. [ABSTRACT FROM AUTHOR]

In this work, a series of chitosan (CS)-grafted carbon oxynitride (OCN) nanoparticles (denoted as CS-OCN) were successfully synthesized for the first time by thermal polycondensation and subsequent esterification. The structure and photocatalytic performance of CS-OCN nanoparticles were investigated. The XPS spectra of CS-OCN-3 showed the presence of amino bonds. The optimal photocatalytic degradation efficiency of the synthesized CS-OCN-3 could reach 94.3% within 390 min, while the photocurrent response intensity was about 150% more than that of pure OCN. The improved photocatalytic performance may be mainly attributed to the enhanced photogenerated carrier's separation and transportation and stronger visible light response after CS grafting. In addition, the inhibition diameter of CS-OCN-3 reached 23 mm against E. coli within 24 h under visible light irradiation, exhibiting excellent photocatalytic bactericidal ability. The results of bacterial inhibition were supported by absorbance measurements (OD600) studies of E. coli. In a word, this work provided a rational design of an efficient novel metal-free photocatalyst to remove bacterial contamination and accelerate the degradation of organic dyes. [ABSTRACT FROM AUTHOR]

Two hybrid composites (SnP@MCM−41 and SnP@SiO2) were fabricated by chemical adsorption of (trans-dihydroxo)(5,10,15,20-tetraphenylporphyrinato)tin(IV) (SnP) on mesoporous structured Mobil Composition of Matter No. 41 (MCM−41) and SiO2 nanoparticles. These materials were characterized by Fourier-transform infrared spectroscopy, ultraviolet–visible spectroscopy, fluorescence spectroscopy, transmission electron microscopy, and field-emission scanning electron microscopy techniques. The incorporation of SnP into MCM−41 and SiO2 supports efficient photocatalytic degradation of the anionic erioglaucine, cationic rhodamine B, and neutral m-cresol purple dyes under visible light irradiation in an aqueous solution. The performances of degradation of these dyes by these photocatalysts under visible light irradiation varied from 87 to 95%. The pseudo-first-order degradation rate constant of organic dyes for SnP@MCM−41 was higher than those of SnP@SiO2 and SnP. These visible light photocatalysts showed remarkable stability and reliable reusability. [ABSTRACT FROM AUTHOR]

The photocatalytic degradation of organic dyes in waste water using carbon quantum dots (CQDs) remains a hot topic due to the importance of environmental protection. However, identifying suitable carbon resources and successful surface modification are still challenging. Herein, the hydrothermal method and surface modification of ammonia and thionyl chloride were applied to synthesize CQDs with different surface groups using PEO106PPO70PEO106 (Pluronic F127) as a carbon source. The average particle size of the as-prepared CQDs was in the range of 2.3–3.5 nm. The unmodified CQDs had the highest relative photoluminescence intensity, while all as-prepared CQDs exhibited abnormal photoluminescence located outside the scope of the visible spectrum. Interestingly, CQDs modified with ammonia achieved a degradation rate of 99.13% (15 d) for 50 mg/L indigo carmine solution, while CQDs modified with thionyl chloride reached a degradation rate of 97.59% (15 d) for light green SF yellowish solution. Therefore, in this work, two typical organic dyes can be effectively photocatalytically degraded by as-prepared CQDs, with suitable surface modification. [ABSTRACT FROM AUTHOR]

Photocatalytic degradation of organic pollutants in wastewater is recognized as a promising technology. However, photocatalyst Bi2O3 responds to visible light and suffers from low quantum yield. In this study, the α-Bi2O3 was synthetized and used for removing Cl− in acidic solutions to transform BiOCl. A heterostructured α-Bi2O3/BiOCl nanosheet can be fabricated by coupling Bi2O3 (narrow band gap) with layered BiOCl (rapid photoelectron transmission). During the degradation of Rhodamine B (RhB), the Bi2O3/BiOCl composite material presented excellent photocatalytic activity. Under visible light irradiation for 60 min, the Bi2O3/BiOCl photocatalyst delivered a superior removal rate of 99.9%, which was much higher than pristine Bi2O3 (36.0%) and BiOCl (74.4%). Radical quenching experiments and electron spin resonance spectra further confirmed the dominant effect of electron holes h+ and superoxide radical anions ·O2− for the photodegradation process. This work develops a green strategy to synthesize a high-performance photocatalyst for organic dye degradation. [ABSTRACT FROM AUTHOR]

Using cetyltrimethylammonium bromide (CTAB) as the surfactant from the precursors of SnCl2·2H2O, the flower-shaped nano composite of tin oxide (SnO2) is prepared by the simple eco-friendly hydrothermal method. We can see that the as-prepared SnO2 sample has a rutile phase crystal structure with regular-shaped nanosheets, and the nanosheets were cross-assembled to form nanoflowers. The band gap of the as-prepared SnO2 sample is 2.26 eV, which is close to the calculated energy gap of 2.58 eV based on density functional theory. The sample is used to degrade the organic dye, and this preliminary application study indicates that the as-prepared SnO2 sample has good stability and reusability in the visible light assisted degradation of methyl orange. Through capture experiments, it is determined that electrons and holes play a major role in the degradation process. The reaction mechanism is also analyzed to indicate the internal relationship between the as-prepared SnO2 samples and its photocatalytic properties. [ABSTRACT FROM AUTHOR]

In the current study, CoFe2O4 and TiO2 nanoparticles were primarily made using the sol-gel method, and subsequently, the hybrid magnetic composites of TiO2 loaded with CoFe2O4 (5–15 percent w/w) were made using a hydrothermal procedure. X-ray diffraction (XRD), Fourier transform infrared (FTIR) and Raman spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM) were all used to thoroughly characterize the materials. Additionally, the zero-charge point (ZCP) determination, the examination of the pore structure by nitrogen adsorption, and an evaluation of magnetic properties were performed. Six organic dye pollutants were selected to evaluate the performance of the synthesized nanocomposites toward photocatalytic degradation, including methylene blue (MB), methyl orange (MO), crystal violet (CV), acridine orange (AO), rhodamine B (RhB), and rhodamine 6G (R-6G). Photodegradation of tetracycline (TL), a model pharmaceutical pollutant, was also studied under UV and visible light. The composites exhibited a high degradation performance in all cases without using any oxidants. The photocatalytic degradation of tetracycline revealed that the CoFe2O4/TiO2 (5% w/w) composite exhibited a higher photocatalytic activity than either pure TiO2 or CoFe2O4, and thus attained 75.31% and 50.4% degradation efficiency under UV and visible light, respectively. Trapping experiments were conducted to investigate the photodegradation mechanism, which revealed that holes and super oxide radicals were the most active species in the photodegradation process. Finally, due to the inherent magnetic attributes of the composites, their easy removal from the treated solution via a simple magnet became possible. [ABSTRACT FROM AUTHOR]

Currently, carbon quantum dots (CQDs) have been widely investigated as an enhancing photocatalytic component of various nanocomposites. In this study, hetero-structures containing carbon quantum dots (CQDs) associated to zinc oxide were prepared following two one-pot procedures: (i) a hydrothermal approach in which commercial ZnO was used as carrier for CQDs; and (ii) an approach in which the ZnO/CQDs samples were produced in situ by adding zinc acetate to an aqueous suspension of CQDs. CQDs were prepared in advance by a low-temperature hydrothermal (LHT) treatment of useless humins wastes produced by the glucose dehydration in an acidic medium. These samples were characterized by several techniques such asadsorption-desorption isotherms of liquid nitrogen at 77K, X-ray diffraction (XRD), infrared diffuse reflectance with Fourier transform (DRIFT) and UV-vis spectroscopy. The photocatalytic behavior of these materials was investigated in the degradation of methylene blue (MB). The obtained results revealed electronic interactions between CQDs and ZnO which have as an effect an enhancement of the charge separation and diminution of the charge recombination. In accordance, a correlation between the photocatalytic activity and the intrinsic properties of ZnO/CQDs has been evidenced. The highest photocatalytic activity corresponded to the heterostructure containing highly dispersed narrow sized CQDs onto ZnO. Under visible light irradiation and after 180 min of irradiation, MB was degraded by as much as 97.6%. [ABSTRACT FROM AUTHOR]

Herein, novel visible light active graphitic carbon nitride (g-C3N4)/sepiolite fiber (CN/SS) composites were fabricated via a facile calcination route, exploiting melamine and thiourea as precursors, and sepiolite fiber as support, for efficient degradation of organic dye methylene blue (MB). The as-prepared CN/SS composites were characterized by various characterization techniques based on structural and microstructural analyses. The effects of CN loading amount, catalyst dosage and initial concentration of dye on the removal rate of dye under visible light were systematically studied. The removal rate of MB was as high as 99.5%, 99.6% and 99.6% over the composites when the CN loading amount, catalyst dosage and initial concentration of dye were 20% (mass percent), 0.1 g, and 15 mg/L in 120 min, respectively. The active species scavenging experiments and electron paramagnetic resonance (EPR) measurement indicated that the holes (h+), hydroxyl radical (·OH) and superoxide radicals (·O2−) were the main active species. This study provides for the design of low-cost, environmentally friendly and highly efficient catalysts for the removal of organic dye. [ABSTRACT FROM AUTHOR]

With an increasing demand for industrial dyes in our daily lives, water conditions have become worse. Recently, the removal of such environmentally hazardous pollutants from wastewaters through photocatalytic degradation has been drawing increased attention. Three mesoporous nanophases of BiFeVOx.y as (Bi2FeIIIV1−yO5.5−y) visible light photocatalysts were synthesized in this study using ethylene glycol-citrate sol-gel synthesis combined with microwave- assisted calcination. X-ray diffraction (XRD), differential thermal analysis (DTA), FTIR spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy coupled with energy dispersive X-ray spectrometry (SEM-EDS), nitrogen adsorption-desorption isotherms, and UV-Vis diffuse reflectance spectrophotometry (UV-Vis/DRS) were used to characterize the BiFeVOx.y photocatalysts. The visible light-induced photocatalytic activities of the BiFeVOx.y phases were evaluated by the degradation of methylene blue (MB) dye in aqueous solution at pH ~10.0. The results of this study show that the combination of doping strategy with the utilization of advanced synthesis methods plays an important role in improving the structure and surface properties of BiFeVOx.y phases, and thereby enhancing their adsorption and photocatalytic efficiencies. The synthesized mesoporous tetragonal γ-BiFeVOx.y nanophase has been proven to be a potential visible-light photocatalyst for the degradation of organic dyes. [ABSTRACT FROM AUTHOR]

Titania (TiO2) is considered to have immense potential as a photocatalyst, the anatase phase in particular. There have been numerous attempts to push the limits of its catalytic activity to higher wavelengths to harness the visible electromagnetic radiation. Most of the investigations till date have been restricted to fine-tuning the bandgap by doping, control of defect chemistry at the surface and several to first principle simulations either with limited success or success at the cost of complexities in processing. Here, we report a simple and elegant way of preparing ceramics through precursor chemistry which involves synthesis of macroporous and mesoporous nanocomposites with in situ formation of TiO2 nanocrystals into a robust and protecting SiOC matrix. The in situ nanoscaled TiO2 is anatase of size 9-10 nm, which is uniformly distributed in an amorphous SiOC matrix forming a new generation of nanocomposites that combine the robustness, structural stability and durability of the SiOC matrix while achieving nanoscaled TiO2 functionalities. The stabilization of the anatase phase even at temperature as high as 1200 °C was evident. With an average pore size of 6.8 nm, surface area of 129 m²/g (BET) and pore volume of 0.22 cm³/g (BET), mesoporosity was achieved in the nanocomposites. The composites exhibited visible light photocatalytic activity, which is attributed to the Ti--O--C/TiC bonds resulting in the reduction of band gap by 0.2 to 0.9 eV. Furthermore, the heterojunction formed between the amorphous SiOC and crystalline TiO2 is also expected to minimize the recombination rate of electron-hole pair, making these novel nanocomposites based on TiO2 extremely active in visible wavelength regime. [ABSTRACT FROM AUTHOR]

This study presents core/shell Ag/SnO2 nanowires (Ag/SnO2NWs) as a new photocatalyst for the rapid degradation of organic compounds by the light from the visible range. AgNWs after coating with a SnO2 shell change optical properties and, due to red shift of the absorbance maxima of the longitudinal and transverse surface plasmon resonance (SPR), modes can be excited by the light from the visible light region. Rhodamine B and malachite green were respectively selected as a model organic dye and toxic one that are present in the environment to study the photodegradation process with a novel one-dimensional metal/semiconductor Ag/SnO2NWs photocatalyst. The degradation was investigated by studying time-dependent UV/Vis absorption of the dye solution, which showed a fast degradation process due to the presence of Ag/SnO2NWs photocatalyst. The rhodamine B and malachite green degraded after 90 and 40 min, respectively, under irradiation at the wavelength of 450 nm. The efficient photocatalytic process is attributed to two phenomenon surface plasmon resonance effects of AgNWs, which allowed light absorption from the visible range, and charge separations on the Ag core and SnO2 shell interface of the nanowires which prevents recombination of photogenerated electron-hole pairs. The presented properties of Ag/SnO2NWs can be used for designing efficient and fast photodegradation systems to remove organic pollutants under solar light without applying any external sources of irradiation. [ABSTRACT FROM AUTHOR]

In this article, five new organic dyes based on the naphthalimide scaffold (Napht-1–Napht-5) were synthesized and tested as high-performance photoinitiators for both the Free Radical Photopolymerization (FRP) of acrylates and the Cationic Polymerization (CP) of epoxides using blue Light-Emitting Diodes (LEDs) as a safe irradiation source (LED @405 nm and 455). In fact, very good photopolymerization profiles (high final conversions and high polymerization rates) were obtained once these photoinitiators were combined with an Iodonium salt (Iod) or Iod/amine NPG and NVK). Remarkably, these dyes were able to generate interpenetrating polymer networks (IPN) by polymerization of a blend of monomers. These experiments were carried out to improve the polymerization profiles as well as the mechanical properties of the obtained materials. Due to their high photoinitiation abilities, these compounds were used in some applications such as photocomposite synthesis, direct laser write, and 3D printing experiments. To determine the chemical mechanisms, the photochemical/photophysical properties of these compounds were studied using different characterization techniques such as UV–visible absorption spectroscopy, steady-state photolysis, Fluorescence quenching, time-resolved fluorescence spectroscopy, FTIR spectroscopy, and cyclic voltammetry [ABSTRACT FROM AUTHOR]

A bismuth oxyiodide (BiOI) photocatalyst with excellent sunlight-driven performance was synthesized by a solvothermal route without the addition of surfactants or capping agents. The prepared photocatalyst exhibited a tetragonal phase with an energy band gap of 2.15 eV. The efficiency of the photocatalyst was elucidated by monitoring the photodegradation of organic dyes and antibiotics. The BiOI photocatalyst provided a 95% removal of norfloxacin (NOR) antibiotics under visible light illumination. Interestingly, the complete removal of Rhodamine B (RhB) dye was achieved after 80 min of natural sunlight irradiation. The photodegradation reaction followed the first-order reaction. Both photo-generated holes and electrons play vital roles in the photodegradation of the pollutant. The BiOI photocatalyst remains stable and still shows a high efficiency even after the fifth run. This confirms the great cycling ability and high structural stability of the photocatalyst. The prepared BiOI catalyst, with a high surface area of 118 m2 g−1, can act as an excellent adsorbent as well. The synergistic effect based on both adsorption and photocatalysis is a key factor in achieving a very high removal efficiency. The photoactivity under sunlight is higher than that observed under visible light, supporting the practical use of the BiOI photocatalyst for the removal of organic pollutants in wastewater through the utilization of abundant solar energy. [ABSTRACT FROM AUTHOR]

A new series of symmetrical organic dyes containing an indigo central core decorated with different electron donor groups have been prepared, starting from Tyrian Purple and using the Pd-catalyzed Stille-Migita coupling process. The effect of substituents on the spectroscopic properties of the dyes has been investigated theoretically and experimentally. In general, all dyes presented intense light absorption bands, both in the blue and red regions of the visible spectrum, conferring them a bright green color in solution. Using the same approach, an asymmetrically substituted D–A-π–A green dye, bearing a triarylamine electron donor and the cyanoacrylate acceptor/anchoring group, has been synthesized for the first time and fully characterized, confirming that spectroscopic and electrochemical properties are consistent with a possible application in dye-sensitized solar cells (DSSC). [ABSTRACT FROM AUTHOR]

The dye wastewater produced in the printing and dyeing industry causes serious harm to the natural environment. TiO2 usually shows photocatalytic degradation of dye under the irradiation ultravilet light rather than visible light. In this work, a large number of oxygen vacancies and Ti3+ defects were generated on the surface of the TiO2 nanoparticles via Ar plasma. Compared with pristine TiO2 nanoparticles, the as-obtained Ar plasma-treated TiO2 (Ar-TiO2) nanoparticles make the energy band gap reduce from 3.21 eV to 3.17 eV and exhibit enhanced photocatalytic degradation of organic dyes. The Ar-TiO2 obtained exhibited excellent degradation properties of methyl orange (MO); the degradation rate under sunlight irradiation was 99.6% in 30 min, and the photocatalytic performance was about twice that of the original TiO2 nanoparticles (49%). The degradation rate under visible light (λ > 400 nm) irradiation was 89% in 150 min, and the photocatalytic performance of the Ar-TiO2 was approaching ~4 times higher than that of the original TiO2 nanoparticles (23%). Ar-TiO2 also showed good degradation performance in degrading rhodamine B (Rho B) and methylene blue (MB). We believe that this plasma strategy provides a new method for improving the photocatalytic activity of other metal oxides. [ABSTRACT FROM AUTHOR]