Search

This study aims to elucidate the possible application of cobalt aluminate nanoparticles (CoAl 2 O 4) as a photocatalyst for the removal of organic dyes. The sol-gel method was employed to synthesise Nd x /CoAl 2 O 4 nanoparticles with varying weight percentages (x = 0.0, 0.2, 0.4, and 0.6 wt %). The experimental investigation focused on the photocatalytic destruction of colour, employing a visible light irradiation source. The structural and optical properties of the synthesised nanoparticle were examined through various analytical techniques, including X-Ray Diffraction (XRD), Ultra Violet-Diffuse Reflectance Spectroscopy (UV-DRS), Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray spectroscopy (EDX), Tunnelling Electron Microscopy (TEM), and X-ray Photoelectron Spectroscopy (XPS). The cubic spinel structure was confirmed through the study of the X-ray diffraction (XRD) pattern of the Nd x /CoAl 2 O 4 nanoparticles. For the compositions x = 0.0, 0.2, 0.4, and 0.6, the nanoparticles exhibited average crystallite sizes of 23.73, 22.99, 21.69, and 21.65 nm, respectively. The synthesised nanoparticle exhibited heterogeneous photocatalytic potential when employed as a model pollutant for the oxidative destruction of crystal violet dye. The experimental findings validated that the CoAl 2 O 4 nanoparticle exhibited a dye degradation rate of 64 % during a 100-min timeframe. Additionally, the 0.6 wt % Nd CoAl 2 O 4 nanoparticle shows a quick dye degradation rate of 91 % for crystal violet dyes when exposed to visible light sources. Hence, the synthesised nanoparticle exhibits catalytic activity and holds potential for utilisation in the treatment of hazardous contaminants in industrial wastewater. [ABSTRACT FROM AUTHOR]

Well-constructed photocatalysts with efficient catalytic activity have attracted much attention due to their efficient visible-light absorption and superior charge separation capability. Visible-light responsive Cu 3 Mo 2 O 9 nanoparticles are synthesized utilising a simple and environmentally friendly green combustion process with Butea monosperma leaf extract as a reducing agent. X-ray diffraction pattern confirms the formation of orthorhombic crystal structure of Cu 3 Mo 2 O 9 NPs corresponding to space group Pnma (62). Furthermore, the synthesized NPs were characterized using FTIR, UV-DRS, PL, SEM and TEM studies. It was found that the direct energy band gap was 2.29 eV. Through photodegradation in the presence of visible light, the dye-sorbed photocatalyst exhibited excellent results. The sorbents have also been examined for recycling, and it has been observed that they maintain their effectiveness even after multiple successive runs. These substances therefore appear to have potential as efficient industrial dye wastewater remediators. Moreover, the high intensity emission in the green zone is amply confirmed by the photoluminescence emission spectra and CIE coordinates. The Latent fingerprints (LFP) are visible with the application of the powder dusting process. The synthesized CMO nanoparticles exhibit ridge patterns that are well-resolved and useful for identifying unique LFP. [ABSTRACT FROM AUTHOR]

[Display omitted] The highly dispersed small-size metal co-catalysts can effectively improve the photocatalytic efficiency of semiconductor photocatalysts by separating photogenerated electrons and enriching active sites. However, this system tends to aggregate in the absence of carrier, resulting in the decrease of active sites. Here, MOF-derived carbon skeleton (MDCS) encapsulated Ni nanoparticles (Ni@MDCS) and BiOBr was loaded onto carbonized cellulose fibers (CCF) with the help of polydopamine (PDA) to construct high-performance and recyclable photocatalytic paper for photocatalytic degradation of organic dyes in water. The characterization results showed that MDCS promoted good dispersion of Ni nanoparticles and provided sufficient active sites. And Ni@MDCS as a co-catalyst accelerated the separation of photogenerated carriers in BiOBr. The PDA improved the loading state of Ni@MDCS on CCF and converted into N -doped C in the carbonization process for further increasing the transfer efficiency of photogenerated electrons. In the composite paper, the stable loading of Ni@MDCS/BiOBr hybrid on CCF improved the dispersion and reusability of photocatalyst. The degradation rate of rhodamine B on CCF/PDA-C/Ni@MDCS/BiOBr paper was as high as 94.6 % after 60 min visible light irradiation, which was about 2.5 times higher than that of CCF/BiOBr paper. During 10 cycles, CCF/PDA-C/Ni@MDCS/BiOBr paper maintained high photocatalytic efficiency and good structural stability. This study provides a new way for developing high-performance and recyclable photocatalytic paper. [ABSTRACT FROM AUTHOR]

Fabrication of efficient perovskite photo-Fenton catalytic systems is recognized as an effective strategy for clean water production. However, modifying perovskite catalysts effectively remains a formidable challenge. In this study, we prepared Bi-doped LaFeO 3 photo-Fenton catalysts using a facile microwave-assisted method. Various characterization techniques confirmed the successful formation of these Bi-doped LaFeO 3 perovskite materials. The photo-Fenton activity of the Bi-doped LaFeO 3 perovskite materials with varying Bi content was assessed by monitoring the degradation of methylene blue (MB) dye solution. Remarkably, the optimized Bi-doped LaFeO 3 (referred to as LBFO3) catalyst achieved approximately 93.64% degradation of MB within 100 min of visible light exposure, demonstrating exceptional efficacy in treating wastewater containing organic dye pollutants. The enhanced photocatalytic activity of the LBFO3 perovskite materials arises from the incorporation of Bi, leading to an expanded optical absorption range, increased specific surface area, and enhanced separation and migration of photo-generated carriers. Importantly, the LBFO3 photo-Fenton system exhibited remarkable stability during four successive cycling treatments, indicating promising practical applications. Additionally, quenching experiments were conducted to elucidate electron transfer in the LBFO3 catalyst related to the photo-Fenton degradation mechanism of MB. This study might pave the way toward designing novel perovskite based photo-Fenton systems for highly efficient degradation of waterborne contaminants. [ABSTRACT FROM AUTHOR]

In this work, a composite ZnO/MoS2/AuNPs supported on carbon fiber cloth (CFC) was prepared by progressively growing ZnO nanorods array, MoS2 nanosheets and AuNPs on CFC for sensitive SERS detection and efficient photocatalytic degradation of organic dye pollutants. The ZnO/MoS2 heterojunctions showed a significant CM effect and further decorating AuNPs with EM effect improved the detection limit of crystal violet (CV) from 10–6 to 10–13 M. The composite can be used for qualitative SERS detection of CV or Nile blue in standard solution or real samples with high stability and good stability. The enhancement mechanisms of CFC/ZnO/MoS2 and CFC/ZnO/MoS2/AuNPs were discussed based on corresponding characterizations and calculations. The composite also showed efficient photocatalysis for dye degradation. The ZnO/MoS2 heterojunction played a key role in enhancing the charge separation rate and improving the photocatalytic performance. The materials achieved degradation efficiencies of 71.4% for CV (1.5 × 10–5 M) after 60 min irradiation under visible light. The active radical species were investigated and possible degradation approach were proposed. Such composite with both SERS enhancement and visible light photodegradation ability has great promise in environment monitoring and remediation. [ABSTRACT FROM AUTHOR]

This study aimed to synthesize a new magnetic photocatalytic nanosystem composed of Ag-CuFe2O4@rGO and to investigate its photodegradation efficiency for two organic pollutants of methylene blue (MB) 4-nitrophenol (4-NP) under visible light irradiation. The synthesized Ag-CuFe2O4@rGO nanocomposites were fully characterized by XRD, TEM, HRTEM, XPS, FTIR, UV and PL analysis which shows well controlled small sized (∼ 10 nm from Scherrer formula) CuFe2O4 NPs with dense and compact loading over rGO sheets. XRD results reveal that cubic spinel structure of CuFe2O4 with nanoparticles (5–10 nm) in shape, which is uniformly, decorated on the surface of the rGO sheets. The band gap energy values of CuFe2O4, Ag-CuFe2O4 and Ag-CuFe2O4@rGO nanoparticles are calculated as 2.76, 2.27 and 2.03 eV, respectively. After incorporation of Ag and rGO into CuFe2O4, the specific surface area was significantly improved to 154 m2/g for Ag-CuFe2O4@rGO nanocomposite. Upon inclusion of the photocatalysts, photodegradation efficiency increased and the Ag-CuFe2O4@rGO composite showed the highest efficiency towards MB (99.5%) and 4-NP (88.7%) followed by the Ag-CuFe2O4. With addition of rGO, the electron-hole recombination declines, thus resulting in a more optimum photocatalytic performance. The rate constant of Ag-CuFe2O4@rGO composite was found to be 0.0985 min−1 for MB and 0.0542 min−1 for 4-NP, respectively. Moreover, the effect of pH, catalyst dosage, and long term stability was thoroughly determined. The improved performance could be attributed to the positive synergistic effect between CuFe2O4 nanoparticles and rGO. The samples were further evaluated by EIS and dynamic photoresponse in order to identify the charge transfer efficiency. The improved photocatalytic mechanism was also explained briefly. [ABSTRACT FROM AUTHOR]

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]

Industrial effluents are a leading major threat for water contamination, subsequently which results in severe health associated risks. Hence, purifying wastewater before releasing into the water resources is essential to avoid contamination. In this study, ZnO/Cu-DPA nano-composites were prepared by altering the percentage of Cu-DPA (20%, 30%, 40%, and 50% which are denoted to be ZnO/20%Cu-DPA, ZnO/30%Cu-DPA, ZnO/40%Cu-DPA and ZnO/50%Cu-DPA) using a simple mechanical grinding process. Several spectroscopic studies were employed such as electron paramagnetic analysis (EPR), powdered X-ray diffractometer (PXRD), UV–Vis absorbance spectroscopy, Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscope to characterize these nano-composites. The photo-catalytic activities of the prepared nano-composites were studied by degrading MB under visible light irradiation. ZnO, ZnO/20%Cu-DPA, ZnO/30%Cu-DPA, ZnO/40%Cu-DPA and ZnO/50%Cu-DPA degradation efficiencies were determined to be 71.8, 78.5, 77.1, and 66.1%, respectively. Among the composite catalysts, the ZnO/20%Cu-DPA coupled system are demonstrated the best efficiency (87%) for photo-degradation of MB within 80 min when exposed to visible light. The ZnO/Cu-DPA nano-composites had a greater MB photodegradation efficiency than pristine ZnO owing to p-n heterojunction in the linked system. Under visible light irradiation, the ZnO/20%Cu-DPA catalysed the conversion of dissolved O2 to hydroxyl radicals (OH·), triggering the reduction of MB. This suggests that ·OH is the primary specific active radical involved in the photo-catalytic decomposition of MB. Furthermore, EPR analysis indicates the existence of ·OH in the photo-catalytic system. The proposed nano-composites (ZnO/20%Cu-DPA) reusability was investigated across three cycles as the most efficient photo-catalyst. The results show that, the ZnO/Cu-DPA nano-catalyst is a potential candidate for the remediation of dirty water. [ABSTRACT FROM AUTHOR]

Here, the zinc sulfide–copper sulfide (ZnS–CuS) nanocomposites have been synthesized using immersing thin layers of ZnS in 0.5 (M) Copper (II) chloride solution at low temperature by a simple and cost-effective chemical bath deposition (CBD) method. The immersion time of ZnS thin films in copper (II) chloride solution was investigated based on the structural, morphological, optical and optical catalytic activity of the prepared layers. The results of X-ray diffraction (XRD) and transmission electron microscopy (TEM) confirmed the formation of CuS: ZnS nanolayers consists of nanocrystals with an approximate diameter of less than 10 nm during the immersion time of 1 min. The particles forming the layers are dense and have good adhesion to the substrate. The energy gap of the layers decreases with increasing copper, which can lead to phase formation. Their significant photocatalytic activities in the photodegradation of Rhodamine B (RhB) dye in aqueous media have been considered, because ZnS:CuS nanocomposite thin films showed light catalytic activity in the RhB degradation in presence of visible radiation, so that the percentage of dye degradation is decreased by increasing the amount of copper and the duration of exposure to visible light due to slowing down the recombination rate of electron–hole pairs. While investigating the optical catalytic activity of the layers, there was no need to homogenize and centrifuge the solution to separate the nanoparticles from it. The main aim of this study is consideration of the effects of CuS amount on the photocatalytic activity of ZnS–CuS nanocomposite under the CBD method of synthesis condition. [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]

Wastewater remediation is a major issue that threatens the ecosystem and health of human population and hence deserves our undivided attention. Dye effluents, in particular those comprising organic colourants from a number of industrial sites, are a major source of wastewater pollution that poses serious dangers to human health and the environment today. Therefore, the goal of this study is to eliminate these coloured effluents, which are present in substantial amounts in wastewater, either singly or in mixtures. In this respect, we present an easy sol-gel synthesis of CoFe 2- x Cr x O 4 (x = 0, 0.2, 0.4, 0.6, 0.8, and 1) nano-ferrites for use as efficient photocatalysts. P-XRD technique was used for the confirmation of cubic spinel nanostructures having crystallite sizes in the nano-regime. Also, the optical band gap values resulted from Tauc plot indicates that incorporation of Cr3+ significantly reduces the band gap values. All the Co–Cr nano photocatalysts can be easily separable using an external magnet as indicated by the magnetic studies. For exploring the photocatalytic activity by photo-fenton process, we chose Rhodamine-B (RhB) as a model dye pollutant. Surprisingly, Cr3+ substitution into cobalt ferrite resulted in a dramatic transformation of the inert CoFe 2 O 4 into a highly visible light active photocatalyst for organic pollutant degradation. The CoFeCrO 4 nanocatalyst showed excellent results for the removal of RhB i.e., 99% removal in 30 min as compared to the CoFe 2 O 4 which was found to be inactive for the degradation. As a result of these exciting photocatalytic results, we were further encouraged to extend the degradation of a few other organic dye contaminants such methylene blue (MB), methyl orange (MO) and the mixture all three dyes (RhB + MB + MO). It was found that CoFeCrO 4 photocatalyst efficiently and swiftly degrades all three dye contaminants individually or in mixture with excellent recyclability and durability. [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]

[Display omitted] The exploration of emerging photocatalysts like covalent organic frameworks (COFs) is an essential but challenging endeavor to find sustainable solutions for selective organic transformations. Anthraquinones are envisaged to construct COFs for visible light photocatalysis because their derivatives are employed industrially as oxidation catalysts or organic dyes. Herein, an anthraquinone COF, TpAQ-COF, is successfully constructed with 1,3,5-triformylphloroglucinol (Tp) and 2,6-diaminoanthraquinone (AQ). Then, the selective oxidation of amines over TpAQ-COF is implemented. Amines can be effectively converted into corresponding imines over TpAQ-COF powered with green light and oxygen, during which superoxide radical anion is discerned as the pivotal reactive oxygen species. This work suggests that COFs could inherit the advantages of molecular building blocks for selective reactions powered with broad visible light. [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]

Ag-ZnO/MWCNT composites were obtained by microwave-assisted, varying-charge synthesis of multiwalled carbon nanotubes (MWCNT). The structural, morphological and optical properties were characterized by: XRD, SEM, TEM, Physisorption of N2 and UVVis. The incorporation of Ag ions and MWNTC caused changes in the structure tension and in the average crystallite size of ZnO. The micrographs revealed that ZnO agglomerates were distributed on the MWNTC and that Ag particles were deposited on the surface of the heterostructure, thus the energy gap decreased. The percentages of degradation of methylene blue were 98 and 75% under ultraviolet and visible radiation, respectively, in the Ag-ZnO/CNT composites. [ABSTRACT FROM AUTHOR]

This article reports preparation of Bi2WO6 using solid-state and solution combustion methods. Different physicochemical characterization techniques such as XRD, SEM, TEM, BET-N2 adsorption study, UV–vis, XPS and photoluminescence spectroscopy were used to examine crystalline phase, optical and morphological properties of synthesized Bi2WO6 samples. The evaluation of prepared photocatalyst for methyl orange degradation, Cr(VI) reduction under visible light and rhodamine B degradation under direct sunlight was carried out. The sample prepared by a solution combustion route, exhibited superior photocatalytic activities than that prepared by a traditional solid-state route. [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]

In this work, α-MnO 2 /BiVO 4 nanocomposites with varying MnO 2 contents (0–7 wt%) were successfully prepared via the simple chemical method. The structure, morphology, and optical properties of prepared nanocomposites were studied by various analytical techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–visible absorption spectroscopy, and photoluminescence (PL) spectroscopy. The photocatalytic efficiency of α-MnO 2 /BiVO 4 nanocomposites was studied via decomposition of rhodamine B (RhB) and tetracycline (TC) under exposure to visible light (λ ≥ 420 nm). Due to good structure and composite advantages, 5%MnO 2 /BiVO 4 (MnBV-5) photocatalyst exhibited superior RhB and TC degradation efficiency to all other samples. In addition, the MnBV-5 photocatalyst showed good stability, and no apparent reduction in photocatalysis efficiency was noted after five testing cycles. Therefore, the MnO 2 /BiVO 4 nanocomposite demonstrated a good potential for photocatalytic decomposition of new water contaminants. [ABSTRACT FROM AUTHOR]

Cobalt coordinated covalent organic frameworks have attracted increasing interest in the field of CO2 photoreduction to CO, owing to their high electron affinity and predesigned structures. However, achieving high conversion efficiency is challenging since most Co related coordination environments facilitate fast recombination of photogenerated electron-hole pairs. Here, we design two kinds of Co-COF catalysts with oxygen coordinated Co atoms and find that after tuning of coordination environment, the reported Co framework catalyst with Co-O4 sites exhibits a high CO production rate of 18000 µmol g−1 h−1 with selectivity as high as 95.7% under visible light irradiation. From in/ex-situ spectral characterizations and theoretical calculations, it is revealed that the predesigned Co-O4 sites significantly facilitate the carrier migration in framework matrixes and inhibit the recombination of photogenerated electron-hole pairs in the photocatalytic process. This work opens a way for the design of high-performance catalysts for CO2 photoreduction. A class of inexpensive aminoanthraquinone organic dyes are shown to facilitate visible-light-driven CO2 reduction. Overall reaction efficiencies were found to be optimal when both electron donating and accepting groups were on a single dye molecule. [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]

The Knoevenagel-Michael cyclocondensation of barbituric acid/1,3-dimethylbarbituric acid, malononitrile, and arylaldehyde derivatives was used to construct a multicomponent green tandem method for the metal-free synthesis of pyrano[2,3-d]pyrimidine scaffolds. At room temperature in aqueous ethanol, photo-excited state functions generated from Na2 eosin Y were employed as direct hydrogen atom transfer (HAT) catalysts by visible light mediated in the air atmosphere. This research looks towards expanding the use of a non-metallic organic dye that is both affordable and readily available. Because of its good yields, energy-effectiveness, high atom economy, time-saving qualities of the reaction, and operational simplicity, Na2 eosin Y is photochemically produced with the least amount of a catalyst. As a result, various ecological and sustainable chemical properties are met. Surprisingly, such cyclization may be carried out on a gram scale, indicating the reaction's potential industrial application. [ABSTRACT FROM AUTHOR]

ZnO films immobilized on SUS316L wire mesh are prepared by a conventional low-temperature hydrothermal method. To improve their photocatalytic activity, we decorate the films with Ag nanospheres using the impregnating photoreduction treatment. The prepared films are characterized using a series of advanced analytical methods. The SEM and EDS results show that continuous films consisting of ZnO nanorods shaped as six-prism cones are formed in the hydrothermal process. Ag0 nanospheres with the dimension from a few to several hundred nanometers decorate the ZnO nanorods. Compared to the individual ZnO film, Ag–ZnO heterojunction improves the absorption of UV and visible light, decreases the bandgap value, and shifts the band position toward more positive potentials. It also inhibits the recombination of photo-inspired electrons and holes, thereby improving the photodegradation ability. The photocatalytic performance of Ag–ZnO composite films increases at most 5.6-fold compared to the bare ZnO film. Active holes (h+), superoxide ( ∙ O 2 - ), and hydroxyl ( ∙ OH ) species play significant roles in organic dye RhB photodegradation under simulated sunlight irradiation. [ABSTRACT FROM AUTHOR]

An efficient eco-friendly photocatalytic method was developed for the synthesis of pharmaceutically highly sought-after quinoxalines. This route is a simple condensation between o-phenylenediamine and an α-hydroxy ketone in methanol at room temperature in the presence of the organic dye Rose Bengal (4,5,6,7-tetrachloro-2',4',5',7'-tetraiodofluorescein) as a photocatalyst. Using this protocol, a library of examples with various ophenylenediamines and α-hydroxy ketones was prepared. This is a practically useful method for the development of quinoxaline derivatives of biological importance in good to excellent yields. [ABSTRACT FROM AUTHOR]

Based on the structure related to the high-temperature superconductor yttrium-barium-copper oxide, two novel high-efficiency visible light photocatalysts were created in this study. The yttrium-barium oxide (YBO) semiconductors Y 2 Ba 3 O 6 (YB3O) and Y 2 Ba 4 O 7 (YB4O) were prepared by a copper-free solid-phase sintering method. They were applied for the effective treatment of dye-containing wastewater by photocatalysis under visible light irradiation. The degradation efficiency of methylene blue (MB) reached more than 95% within 10 min. Stable visible light degradation of methyl orange (MO) was achieved in the presence of YB3O and YB4O. The electron spin resonance technique and active substance capture technique confirmed the presence of superoxide radicals (·O 2 −), hydroxyl radicals (·OH) and holes (h VB +) under visible light illumination. UV–Vis diffuse reflectance spectroscopy analysis showed that the direct optical band gaps of YB3O and YB4O were 2.550 eV and 2.583 eV, respectively, which resulted in their high visible absorption at 486.27 nm and 480.06 nm. After five cycles, the recoveries of YB3O and YB4O reached 67.15% and 72.98%. Therefore, YB3O and YB4O are considered as powerful semiconductor catalysts for the photocatalytic degradation of organic dyes in wastewater. • Synthesis of yttrium -barium oxide (YBO) visible light catalyst. • Y 2 Ba 3 O 6 (YB3O) and Y 2 Ba 4 O 7 (YB4O) show a forbidden band width of 2.550 eV and 2.583 eV respectively. • The effective degradation of methylene blue was achieved within 10 min under visible light. • The mineralization of the total organic carbon in the degraded solutions of both dyes reached close to 80%. [ABSTRACT FROM AUTHOR]

Nickel–aluminum-layered double-hydroxide (Ni–Al LDH) was synthesized via a facile and green route of co-precipitation. Systematic characterizations of the synthesized material were done by different instrumental techniques. The morphology of the Ni–Al nanomaterial was observed to be sheet-like structures as indicated by FESEM images. From the XRD measurements, it was confirmed that the as-grown nanosheets were Ni–Al LDH nanomaterials with a small quantity of aluminum oxide. Further, the Ni–Al LDH nanomaterial was tested as a photocatalyst for the solar and adsorption-assisted removal of organic pollutants from wastewater. Organic compounds of acridine orange (AO), methyl orange (MO) and cresyl blue (CB) were used as model organic pollutants in this study. Among the three dyes, the Ni–Al photocatalyst was found best for the MO removal while performing the reaction under the dark and visible light conditions. During experiments, it was found that Ni–Al LDH decolorized the MO containing wastewater up to 50% by the process of adsorption performed in the dark conditions. The decolorization efficiency was increased under the visible light as 87% decolorization of MO was achieved from its 0.03 mM solution due to the dye degradation by the action of Ni–Al LDH as a photocatalyst. [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]

With the millions of dyes being used in textile industries, there is a challenge for humanity to remediate the waste fluid emerged from these industries and provide a solution to protect the natural water around us. In this context, we report the manufacturing process to develop nanofunctionalized, electroformed tube for the degradation of Azo dyes which are considered as poorly biodegradable industrial pollutants. Copper/graphene oxide electroform tubes have been developed via in-house pulse electroforming setup. Vertically grown ZnO nanorods were synthesized over electroformed electroform tube via chemical synthesis route and were characterized using scanning electron microscopy, energy dispersive spectroscopy, X-ray diffractometer, UV–Vis diffuse reflectance spectrophotometer, and microhardness test. The as-synthesized substrates were utilized for photodegradation of organic dyes under sunlight irradiation. The targeted dyes for evaluation of photocatalytic efficiency are methyl orange (MO), and methylene blue (MB). The results reveal that copper/graphene–zinc oxide electroform tubes provides higher photodegradation efficiency 98.24% in 120 min for MO, and 98.95% in 135 min for MB dye. The proposed functional composite platform can be envisioned for scaling it up for large volume waste water treatment in textile industries. [ABSTRACT FROM AUTHOR]

In spite of the efficient redox properties of CeO2 originating from the easy inter-conversion of the Ce4+/Ce3+ couple, its large band gap (~ 3 eV) limits its photocatalytic application. Herein, we report a novel one-pot method to synthesize phase-pure Mn-doped CeO2 nanoparticles (average size ~ 7 nm) well dispersed in a network of carbon nanotubes (CNT) and also attached onto the CNT surface, as confirmed by transmission electron micrographs. The Mn and CNT content in ceria were optimised based on ability for synergistic sorptive-photocatalytic removal of a model cationic dye under UV–visible light. Diffuse reflectance spectra revealed narrowed optical band gap (only ~ 1.8 eV) in the optimised visible light active Mn-CeO2/CNT nanohybrid resulting from increased defect states due to multivalent Mn dopants (confirmed by X-ray photoelectron spectroscopy). N2 adsorption–desorption data confirmed large increase in the specific surface area compared to ceria nanoparticles leading to improved dye adsorption. The arrest of recombination of photogenerated carriers (suggested by photoluminescence quenching) due to conductive CNT support further contribute to enhancing photocatalytic activity. Thus, the findings presented in this article are relevant to materials research for environmental remediation from a surface and band gap engineering point of view. [ABSTRACT FROM AUTHOR]

In this study, BiOBr microspheres were successfully synthesized through a facile solvothermal route in the presence of glycerol. The photocatalysts were characterized using X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The morphology of BiOBr-6, which was synthesized using glycerol, comprised flower-like structures with diameters of ∼2 μm, which were composed of two-dimensional flakes with the sizes of tens of nanometers. The photocatalytic activity of the optimized BiOBr-6 was evaluated through the photocatalytic degradation of rhodamine B, methylene blue, methyl orange, and chrome blue-black R under visible light irradiation. Within 60 min, the degradation rates of Rh B、MB and MO reached 99.7 %, 99.6 % and 98.1 %, and within 90 min，the degradation rates of C-R reached 98.0 %. We concluded that the highly visible-light-driven catalytic performance of the flower-like BiOBr sample was associated with its high surface area, porous structure, and low bandgap energy, as well as its unique microsphere morphology. The resulting BiOBr microspheres may serve as promising adsorbents and photocatalysts for the treatment of organic pollutants. • BiOBr-6 exhibited the excellent photocatalytic degradation efficiencies on organic dyes. • BiOBr-6 possess a large specific surface area. [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]

The multifunctional ternary magnetic core/semiconductor/noble-metal nanocomposites have received considerable concerns because they can realize the integration of photocatalytic degradation, surface-enhanced Raman scattering (SERS) detection and magnetic separation to target organic waste water. Herein, the Fe 3 O 4 /Cu 2 O/Au nanocomposites were prepared through wet-chemical and in-situ reduction reactions. The influence of content of Au nanocrystals immobilized on the surfaces of Fe 3 O 4 /Cu 2 O on the photocatalytic and SERS performance of Fe 3 O 4 /Cu 2 O/Au nanocomposites was investigated. Photoluminescence (PL) results showed that Fe 3 O 4 /Cu 2 O/Au nanocomposites possessed higher photocurrent response compared with Fe 3 O 4 /Cu 2 O nanocomposites. And Fe 3 O 4 /Cu 2 O/Au nanocomposites exhibited stronger absorption of visible light owing to the localized surface plasmon resonance (LSPR) effect of Au nanocrystals. Methylene blue (MB) and malachite green (MG) were chosen as the photocatalytic degradation and detection targets to verify photocatalytic property and SERS characteristic of Fe 3 O 4 /Cu 2 O/Au nanocomposites. Results indicated that the photocatalytic efficiency and SERS signal intensity of Fe 3 O 4 /Cu 2 O/Au nanocomposites were improved significantly along with the increase of Au contents. The universal applicability of Fe 3 O 4 /Cu 2 O/Au nanocomposites was also evaluated by detecting SERS signals of residue of MB in fish. Our work offers exciting opportunities to acquire the multifunctional material for SERS trace detection and photocatalytic elimination to organic pollutants and will have more hopeful prospects in efficient catalytic and highly sensitive detection applications. • Fe 3 O 4 /Cu 2 O/Au nanocomposites (NCs) were prepared by wet chemistry reaction process. • Effect of Au content on catalytic activity of Fe 3 O 4 /Cu 2 O/Au NCs was studied. • Mechanism of photocatalytic reaction of dyes by Fe 3 O 4 /Cu 2 O/Au NCs was investigated. • Fe 3 O 4 /Cu 2 O/Au NCs achieved integration of photocatalysis and SERS detection. • Limit of detection of Fe 3 O 4 /Cu 2 O/Au NCs for MB and MG was as low as 10−11 M. [ABSTRACT FROM AUTHOR]

In this work, we have synthesized MoS2 nanosheets (NSs) through hydrothermal as well as liquid-phase sonication methods and studied their ability to degrade organic dyes, methyl red (MR) and methylene blue (MB) under visible light irradiation. The as-synthesized photocatalysts have been characterized by powder X-ray diffraction, Raman Spectroscopy and transmission electron microscopy to confirm their structure and surface morphology. XRD patterns show that crystalline nature of MoS2 NSs prepared by hydrothermal method appears at 160°C for 15 h. In contrast, sharp and intense diffraction peaks appear for liquid exfoliation method even at room temperature, exhibiting better crystallinity of the as-prepared NSs. The difference (∆) of ~25 cm−1 between E12g and A1g modes of Raman spectra indicates formation of 5–6 layers of MoS2 from both the synthesis routes. UV–Vis spectroscopy has been utilized to study the degradation of dyes by MoS2 NSs as catalyst. Hydrothermally assisted synthesis of MoS2 NSs exhibit lesser degradation efficiency with 58.92% for MR and 49.28% for MB, while exfoliation-assisted MoS2 NSs act as better photocatalyst with 63.40 and 62.40% degradation of MR and MB, respectively. Faster degradation rate for MR compared to MB has been attributed to the presence of lesser chromophoric sites in MR. [ABSTRACT FROM AUTHOR]

g-C3N4 and rare earth (RE)-doped (Yb, Nd and Ce) g-C3N4 nanosheets were synthesized by a thermal method. The remarkable effects of RE doping on the structural, morphological, and optical properties of g-C3N4 were investigated using XRD, FT-IR, SEM, BET, XPS, UV–Vis, PL, EIS and Mott–Schottky characterization techniques. The photocatalytic activities of RE doped g-C3N4 nanosheets for different dyes were improved compared with g-C3N4 under visible light irradiation, among which Ce/g-C3N4 showed outstanding performance. Due to the doping of RE, it modulates the electronic structure of pristine g-C3N4 and broadens its optical absorption range. In addition, a possible mechanism of photocatalytic degradation of dyes was propounded by free radical trapping experiments. This work may provide a reference for the rational design of photocatalysts and inspiration for the photocatalytic mechanism. [ABSTRACT FROM AUTHOR]

Ti 3 C 2 MXenes were constructed via different strategies using HF-forming etchants or HF as etchants and were subsequently modified through alkalization to replace –F with O-containing terminal functional groups. Various analytical techniques were used to fully characterize all fabricated materials for confirming the formation of species with the desired morphologies and properties. ML-Ti 3 C 2 , etched with HF, presented a multilayered structure that made it resemble an accordion, while DL-Ti 3 C 2 , prepared using HF-forming etchants, was not completely etched, with some amounts of the parent compound's Al remaining in unformed vague laminated structures. ML-Ti 3 C 2 alkalization yielded ML-Ti 3 C 2 (OH) 2 , which was characterized by large amounts of O-containing functional groups and greatly enhanced porosity compared with that of ML-Ti 3 C 2. Methylene blue (MB) adsorption and photocatalytic degradation tests were then conducted to evaluate the functionalities of ML-Ti 3 C 2 (OH) 2 by putting it into direct application instead of being used as catalyst promoters. ML-Ti 3 C 2 (OH) 2 achieved adsorption–desorption equilibrium using MB in the dark within 30 min and 81.2% of MB was then selectively degraded over 120 min under simulated visible light irradiation. A possible degradation mechanism was proposed on the basis of the results of radical quenching experiments. This study offers a unique mechanism for directly applying MXene to the adsorption–photocatalytic degradation of organics in wastewater. For Preparation and regulation of two-dimensional Ti 3 C 2 T x MXene for enhanced adsorption-photocatalytic degradation of organic dyes in wastewater. [Display omitted] [ABSTRACT FROM AUTHOR]

Synthetic organic colourants are extremely prominent in heritage collections, particularly throughout textiles. They are often generalized as highly light-sensitive; although, a broad distribution of lightfastness exists. This is evident in various fastness ratings published in late nineteenth century literature, the work of Schultz and Julius, and the Colour Index. In heritage conservation, much of the research related to light-sensitivity of dyed textiles has focused on natural colourants. This is likely due to a general interest in the dyes present on older objects, and the overwhelming selection of modern synthetic materials. To address this gap, a shortlist of targeted synthetic dyes was recently developed using census data for dye production and imports in the United States, and information gathered from the Colour Index. Our present work provides a follow up to the prior literature review, where a subset of samples from the published target list was used to evaluate lightfastness. To begin the study, a collection of dyed textiles from the last quarter of the nineteenth century was gathered from trade publications of the period, and those matching the target criteria were reserved for analysis. The lightfastness of more than 100 early synthetic dyes was then investigated using the historic materials. Test specimens were illuminated with a custom-built fadometer containing an LED light source that is characteristic of modern gallery lighting. Four batches of samples were exposed at 20 klx for approximately 6 months each, and diffuse reflectance was periodically measured with a portable spectrophotometer over white and black backgrounds. Measurements were taken at increasing light dose values to reach at least 85 Mlx·h per batch. Visible reflectance spectra were recorded in a dataset to document the colours as a function of light exposure, and foster future colorimetry research. Colour change was also calculated using the CIEDE2000 formula to assess lightfastness, and results were summarized as a resource to further develop risk analysis tools for exhibit lighting. In this paper, a detailed description of the test apparatus is presented with an overview of the lightfastness results and the resulting dataset. Comparisons are given with nineteenth century lightfastness data, and ISO values available in the Colour Index. It is hoped that the associated dataset will provide a foundation to be expanded over time with interest in further materials and test methods. [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]

Graphitic carbon nitride (g-C3N4) is a metal-free photocatalyst with visible light response. However, the disadvantages limit its application in a wider range, such as its small specific surface areas, fewer active sites, narrow visible light absorption range and high photogenic carrier recombination. In this paper, NaOH was used as an activator for alkaline activation of g-C3N4. The phase composition, micromorphology, surface chemical state and optical properties of g-C3N4 after activation were tested. The photocatalytic performance of g-C3N4 over organic dyes was also tested. The results showed that Na+ entered the interlayers of g-C3N4, expanding the spaces between layers. The specific surface area and pore volume of powder were increased. The active sites were increased. The band gap was decreased, and the photogenic carrier recombination was reduced. Alkaline activated g-C3N4 had better adsorption and degradation performance over rhodamine B and methyl orange than inactivated g-C3N4. Therefore, the alkaline activated g-C3N4 promotes its further application in the field of wastewater treatment. This work sheds light on the material modification through a simple method with the aim to efficiently use solar energy. [ABSTRACT FROM AUTHOR]

Ni-doped γ-Bi 2 O 3 was successfully synthesized via a one-pot oil bath synthesis. The prepared materials were characterized by XRD, DLS, SEM, FT-IR, EDS, TEM, and XPS. The XRD patterns confirmed the pure phase formation of tetrahedral γ-Bi 2 O 3. The material was tested for the degradation of various organic dyes and exhibited outstanding efficiency and selectivity for the photodeterioration of Congo red compared to other organic dyes. Furthermore, different Ni percentages were doped to find the best possible photocatalyst for Congo red degradation, with the 2 % Ni-doped γ-Bi 2 O 3 exhibiting an improved performance. The photocatalytic degradation efficiency of Congo red reached 93 % after 80 min and was used for three consecutive cycles without a considerable decrease in activity. UV–visible DRS spectra and the Mott-Schottky plot were used to understand the energy diagram of the materials. The higher visible light absorption and charge separation efficacy of the photogenerated electron-hole pairs induced by Ni loading contributed to improved photocatalytic performance. This study introduces a novel method for synthesizing Ni-doped tetrahedral γ-Bi 2 O 3 microstructures with precisely controlled morphology for the selective degradation of Congo red dye. [Display omitted] • Ni-doped γ-Bi 2 O 3 was synthesized via a novel facile one-pot oil bath synthesis. • This is the first photocatalysis work using the Ni-doped γ-Bi 2 O 3 phase. • The material exhibited outstanding selectivity for the degradation of Congo red. • The efficacy of Congo red reached 93 % after 80 min with 2 % Ni-doped γ-Bi 2 O 3. [ABSTRACT FROM AUTHOR]

A novel photocatalyst composed of bismuth molybdate (Bi 2 MoO 6 , BMO) coupled with rhodium (Rh) nanoparticles was synthesized and evaluated for its efficiency in degrading dye contaminant under visible light irradiation. The BMO/Rh composite demonstrated a significant enhancement in photocatalytic performance, achieving a 40 % higher degradation rate of Rhodamine B (RhB) compared to bare BMO. Enhanced charge separation and reduced electron-hole recombination were primarily attributed to the synergistic effects introduced by the Rh nanoparticles. Extensive characterization techniques provided insights into the structural and mechanistic aspects of the photocatalyst. Stability tests confirmed that BMO/Rh maintained over 95 % of its initial activity after five consecutive reaction cycles, highlighting its durability. Scavenger experiments identified superoxide radicals (•O 2 -) and hydroxyl radicals (•OH) as the primary active species, contributing to the high efficiency of dye degradation. This study underscores the potential of BMO/Rh hybrids as sustainable and effective photocatalysts for environmental remediation. • Enhanced a BMO/Rh photocatalyst that improves dye degradation by 40 % under visible light. • Achieved improved charge separation with Rh nanoparticles, reducing electron-hole recombination. • Maintained over 95 % photocatalytic activity after five cycles, demonstrating high stability. • Quantified active radicals' roles in improving dye degradation efficiency. [ABSTRACT FROM AUTHOR]

Designing of an effectual heterostructure photocatalyst for catalytic organic pollutant exclusion has been the subject of rigorous research intended to resolve the related environmental aggravation. Fabricating p-n junctions is an effective strategy to promote electron-hole separation of semiconductor photocatalysts as well as enhance the organic toxin degradation performance. In this study, a series of n-type NiAlFe-layered triple hydroxide (LTH) loaded with various ratios of p-type MoS 2 was synthesized for forming a heterostructure LTH/MoS 2 (LMs) by an in situ hydrothermal strategy. The photocatalysts were characterized by XRD, SEM&EDX, TEM, FT-IR, XPS, as well as UV–vis DRS. The photoactivity of photocatalysts was tested by the degradation of Indigo Carmine (IC) dye. The optimized catalyst (LM1) degrades 100% of indigo dye in high alkaline pH under UV light for 100 min. Besides, the degradation rate of LM1 is 15 times higher than that of pristine NiAlFe-LTH. The enhanced photoactivity is attributed to the synergistic effect between NiAlFe-LTH and MoS 2 as well as the p-n junction formation. [Display omitted] • A facile method for synthesizing heterostructure-LMs photocatalyst is suggested. • The best photocatalytic performance was found in LM1 samples for dye degradation. • Superior adsorptive-photocatalytic activity of LM1 was revealed under visible light. • Photocatalytic performance of LMs was effectively exhibited even at high pH over 11. • The recyclability and mechanism of photocatalysis of LMs was identified. [ABSTRACT FROM AUTHOR]

In pursuit of the appropriate method for complete removal of organic effluents from surface water, Ag modified g-C 3 N 4 materials as a photocatalyst gained considerable attention. In this paper, Ag doped g-C 3 N 4 materials were prepared by a facile one-pot pyrolysis method. The synthesized photocatalysts were studied using different analytical techniques like XRD, HR-TEM, XPS, UV, FTIR, PL spectroscopy, etc. The prepared photocatalyst materials were used for the visible light photodegradation of IC dye as an organic pollutant and for self-cleaning applications. The obtained results indicate that the optimized Ag doped g-C 3 N 4 (CNA-1) sample exhibits 79.97 % degradation efficiency in 30 min with efficient self-cleaning performance. The enhanced photocatalytic activity of CNA-1 can be attributed to the incorporation of Ag, which plays a pivotal role in absorbing visible light. Furthermore, cycling tests were employed to evaluate the stability and reusability of material. The possible photocatalytic mechanism was proposed from trapping experiments. [Display omitted] [ABSTRACT FROM AUTHOR]