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In this paper, three-dimensional TiO2 nanoflowers (NFs) were prepared by a facile hydrothermal method, and Ag3PO4 was grown in situ following alkali treatment to design and synthesize a Ag3PO4/OH/TiO2 catalyst with excellent photocatalytic activity under visible light. The test results show that the photocatalytic degradation performance of TiO2 NFs after alkali treatment and Ag3PO4 loading is significantly improved. This is because the alkali treatment and the introduction of Ag3PO4 can provide a large amount of –OH, which can be converted to ˙OH under UV irradiation, followed by an increase in the number of active radicals to enhance the photocatalytic degradation performance. Meanwhile, the introduction of Ag3PO4 can effectively improve the light absorption ability of the photocatalyst. Moreover, the in situ growth of Ag3PO4 on TiO2 NFs can construct a high-quality Ag3PO4/TiO2 heterojunction to promote the charge separation and transport. Therefore, the degradation rate of Ag3PO4/OH/TiO2 can reach 90% after 30 min for degrading 3 mg L−1 RhB under visible light. The Ag3PO4/OH/TiO2 photocatalyst designed in the present work provides a new tool for the degradation of organic dyes. [ABSTRACT FROM AUTHOR]

Bismuth oxybromide (BiOBr) nanoflowers were anchored onto kaolinite nanosheets via a calcination method. Assisted by characterization methods including XRD, SEM, and XPS, the microstructures of photocatalysts were comparatively investigated. The findings revealed a close integration of BiOBr nanoflowers with kaolinite, resulting in a gradual phase transition and augmented surface oxygen. Furthermore, the photocatalytic performance was assessed by investigating the degradation of organic dyes under visible light irradiation. Notably, the experimental results demonstrated that the degradation efficiencies of BiOBr/kaolinite composites were higher than that of pure BiOBr. The ⋅O2− was proven to be the major active radical in the photocatalytic process. This study presents a straightforward approach for fabricating BiOBr‐based photocatalysts, showcasing their enhanced performance in organic dye degradation under visible light. [ABSTRACT FROM AUTHOR]

The construction of photocatalysts with a Z-scheme heterojunction is considered to be a superior strategy for improving photocatalytic activity. In this study, a photocatalyst (PI/TiC/TiO2) with a Z-scheme heterojunction was fabricated, in which polyimide (PI) and TiO2 were used as the organic/inorganic semiconductor photocatalyst and TiC acted as the transmission bridge for electrons between PI and TiO2. In the self-made air flow photocatalytic reactor, the photocatalytic degradation efficiencies of organic dyes by PI/TiC/TiO2 increased with the increase of both the concentration and diffusion rate of O2. The degradation efficiencies of RhB and MB by PI/TiC/TiO2 reached 93.87% and 90.96%, respectively, within 90 min of visible light exposure, showing its outstanding photocatalytic performance. The mechanism analysis indicated that the Z-scheme heterojunction in PI/TiC/TiO2 facilitated the separation and migration of photoexcited charges while retaining stronger redox capabilities for charge carriers. This study provides an insight into the construction of visible light responsive organic/inorganic photocatalysts with Z-scheme heterojunctions for organic pollution treatment applications. [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]

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]

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]

Remediation of organic dyes from wastewater in textile industries is a big challenge to decreasing water pollution. This study was aimed at the preparation of ZnO nanoparticles (NPs) and their application as a photocatalyst for the degradation of methylene blue (MB), sunfix red (SR) and real textile wastewater (RTW) under both UV and visible irradiations. The ZnO NPs were synthesized with a green Thymus vulgaris leaf extract-supported approach following the calcination process. 50 mg L−1 MB and 50 mg L−1 SR dyes were completely photodegrade under UV irradiation after only 20 and 45 minutes, respectively, in the presence of 1.0 mg/mL ZnO NPs. When they are exposed to visible light, the degradation efficiency reached 91 and 75% within 60 and 120 min, respectively. Photocatalytic measurements of RTW depict that 95% (within 60 min under UV illumination) and 79% (within 90 min under visible illumination) were degraded, respectively. The enhanced photodegradation can be attributed to the narrowing of the bandgap of the ZnO NPs, high crystallinity and nearly hexagonal morphology with an average size of 20–30 nm. The present results show that ZnO NPs could potentially be applied for high-efficiency degradation of organic dyes and RTW under both UV and visible light irradiation. We report for the first time, Thymus vulgaris leaf extract–assisted synthesis of ZnO nanoparticles (NPs) has been applied as a photocatalytic dye and RTW degradation. Second, our synthesis approach is more facile and simple than the previous method where complex hydrothermal or solvothermal methods have been applied, which leads to a complex preparation procedure. We systematically prepared ZnO materials in taking account into the variable Thymus vulgaris/ZnO precursor ratio, different calcination temperature and time and in detail, their photocatalytic activity has been fully investigated. [ABSTRACT FROM AUTHOR]

The functionalized NiFe‐LDH with photosensitized GQDs were synthesized through the hydrothermal route by differing the amount of GQDs solution and studied its efficacy towards the mineralization of textile dyes under visible light. The synthesized samples were characterized by XRD, FESEM, HRTEM, DRUV‐Vis, RAMAN, XPS, and BET. The combined effect of the hexagonal carbon lattice in GQD and open layered porous structure of NiFe‐LDH nanosheets results in the contraction of the lattice. Different reactive and conventional dyes were taken as representative dyes to evaluate the activity of the as‐synthesized photocatalysts. The enhanced electron absorption/donor effect between GQDs and NiFe‐LDH, and the growth of oxygen‐bridged Ni/Fe−C moieties enable the composite to exhibit better photocatalytic activity. Both photocatalytic activity and characterization results confirmed that the GQD@NiFe‐LDH nanocomposite heterostructure synthesized at 160 °C by taking 10 mL of GQDs aqueous solution named GNFLDH10 has a higher degree of crystallinity and has the best photocatalytic efficiency compared to other reported visible light catalysts. Specifically, the above optimized GQD@NiFe‐LDH photocatalyst is capable of photo‐mineralizing 50 ppm of Reactive Green in 20 min, Reactive Red in 20 min, and Congo Red in 25 min respectively following a direct Z‐scheme mechanism with substantial reusability. [ABSTRACT FROM AUTHOR]

In the past decades, great efforts have been made to develop novel visible‐light photocatalysts to achieve high photocatalytic efficiency by utilizing visible light, the largest proportion of solar energy. As a new type of photocatalyst materials, all‐inorganic lead‐free halide double perovskites have begun to attract widespread interest. Herein, double perovskite Cs2AgBiCl6 was developed into a visible‐light photocatalyst for degrading organic dyes. Cs2AgBiCl6 was prepared by the hydrochloric acid precipitation and anti‐solvent recrystallization methods, respectively, and was used to degrade organic dyes under visible light. Samples prepared by the anti‐solvent recrystallization method are smaller than those prepared by the hydrochloric acid precipitation method, which can degrade 95.7 % of Sudan III in 10 min and show excellent photocatalytic activity. The cyclic experiments demonstrate that Cs2AgBiCl6 has a good cycle stability. Moreover, Cs2AgBiCl6‐AS also exhibits good photocatalytic degradation ability for Methyl red and Malachite green. These distinctive results indicate that Cs2AgBiCl6 may be a promising material for developing novel, high‐efficient and stable visible‐light photocatalysts. [ABSTRACT FROM AUTHOR]

In this research, four bimetallic nanocomposites (BNCs) of copper and silver with weight ratios (0.9:0.10, 0.92:0.08, 0.94:0.06, 0.96:0.04) formulated and specified as (Cu0.90@Ag0.10), (Cu0.92@Ag0.08), (Cu0.94@Ag0.06), and (Cu0.96@Ag0.04) were prepared via the green synthesis in the presence of Citrus paradisi extract as a low cost, simple and environmentally friendly method. The as-prepared Cu@Ag BNCs were identified by FTIR, XRD, EDX, FE-SEM, and EDX mapping analyses. The FTIR analysis was performed to determine the functional groups in Cu@Ag BNCs. EDX analysis confirms the existence of Cu and Ag in BNCs. These Cu@Ag BNCs were used as catalysts for the photodegradation process of methyl orange (MO) and indigo carmine (IC) as the anionic organic dye. The effect of parameters such as different weight percentages of BNCs constituent metals, the amounts of photocatalyst and hydrogen peroxide on the degradation rate of MO and IC under visible light was investigated and their optimal values were determined. The optimized conditions for removal of the dyes in the natural pH and 0.005 g of photocatalyst Cu0.90@Ag0.10 BNCs reached for degradation dyes MO and IC to 90.0% and 100% respectively. [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]

A novel n-MgFe2O4–n-ZnS heterojunction catalyst was employed via two step approach for photodegradation of organic dyes such as Methylene Blue (MB) and Crystal Violet (CV) dyes under visible light irradiation. The synthesized MgFe2O4/ZnS NCs were characterized using PXRD, FTIR, UV–Visible spectroscopy, PL and FESEM analysis which reveals the formation of flake like structure with size as to be ~ 50 nm. The photocatalytic experimental result demonstrates that the MgFe2O4/ZnS nanocomposites (NCs) improve photodegradation performance with 98.0% and 91% decomposition of MB and CV dyes within 120 min illumination during simulated visible light irradiation. From the result, MgFe2O4/ZnS NCs has higher photocatalytic performance than that of MgFe2O4, and ZnS due to efficient separation of the photo-induced electron–hole pairs and effective electron–hole generation transfer by the formation of n-MgFe2O4–n-ZnS heterojunction. Hence, photodegradation performance implies that the synthesized MgFe2O4/ZnS NCs can be effectively utilized in waste water purification systems. [ABSTRACT FROM AUTHOR]

PAN/TiO2/CNT and PAN/TiO2/CNT-PVA composite nanofibrous membranes with photocatalytic activity were successfully synthesized using electrospinning. The effect of CNT concentration and PVA coating on the membrane surface toward the membrane performances was investigated. TiO2 anatase phase was exist on the respective membranes. SEM morphological investigation revealed the random orientation of the nanofibers with beads decorated in each strand. The PAN/TiO2/CNT composite nanofiber membrane exhibited high performance for the removal of cationic organic dye methylene blue (MB) in a cross-flow photocatalytic membrane reactor under low power visible light of LED lamp (14.5 W) and a constant pollutant flow rate of 0.21 L/min. The presence of TiO2/CNT photocatalyst was proven to prolong the lifetime of the photocatalytic membrane and retard membrane fouling to the maximum extent. PAN/TiO2/CNT membrane has displayed 100% MB rejection for the first 8 h of operation. Both, PAN/TiO2/CNT and PAN/TiO2/CNT-PVA maintained their membrane performances and did not show major flux decline even after five recycling uses. The incorporation of TiO2/CNTs on PAN nanofibers has resulted in a durable photocatalytic membrane for the effective removal of dye waste using a cross-flow membrane reactor. [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]

We demonstrate a low-cost, simple-operation, and environmentally friendly magnetic grinding synthetic process to prepare nontoxic copper sulfide-based composites with photocatalytic activity. Using this efficient approach, CuS/ZnS and CuS/CdS composites were successfully synthesized from elemental powders without using any other additives or solvents. The formation of metal sulfides was confirmed using a series of characterizations. The photocatalytic activities of the as-prepared materials were evaluated by the degradation of methylene blue (MB), rhodamine B (RhB), and methyl orange (MO) dyes in the presence of hydrogen peroxide (H2O2), which served as an oxidant under visible irradiation. The degradation efficiencies of MB and RhB by CuS/ZnS and CuS/CdS composites were more than 95% in 30 min and the degradation efficiency of MO was more than 85% in 90 min. The photocatalytic activities of the CuS/ZnS and CuS/CdS composites were better than those of pure metal sulfides. In addition, the CuS/ZnS and CuS/CdS composites showed good stability toward photocatalytic degradation and their main reactive species for degrading organic dyes are photogenerated hydroxyl radical (˙OH). Reasonable photocatalytic reaction mechanisms are proposed to explain the photocatalytic processes of the CuS/ZnS and CuS/CdS composites. [ABSTRACT FROM AUTHOR]

A new type of visible light Z‐scheme Bi2O3‐Ag3PO4 composite photocatalyst was created in this work using a simple in‐situ precipitation process. On this basis, the morphology, optical properties and electrochemical performance of the photocatalyst were studied by N2 adsorption‐desorption analysis and XRD, FT‐IR, XPS, SEM, TEM, UV‐vis DRS, PL, EIS, and other characterization methods. To further explore the photocatalytic performance of the composites, visible light degradation experiments were carried out on the antibiotic TC and the organic dyes MB and MO. The results show that the 0.025BA composite material exhibits higher photocatalytic performance than other comparative samples. In addition, the 0.025BA composite after five cycles of experiments also has a satisfactory photodegradation rate. The active species capture experiment and ESR showed that the active species h+, ⋅O2− are the main factors affecting the photocatalytic degradation, and ⋅OH played a minor role. The intermediates and possible decomposition pathways of TC were illustrated through LC–MS technology. Finally, the possible photocatalytic reaction mechanism was speculated. On the whole, the high photocatalytic activity of the 0.025BA composite is perhaps the result of the formation of its Z‐scheme heterojunction, which enables fast transfer and high separation of photogenerated carriers at the heterojunction interface, and also accelerates the rate of redox reactions on electron‐hole pairs. [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]

The development of high-efficiency photocatalytic materials responsive to visible light is one of the most effective ways to address the environmental threats posed by organic dyes in industrial wastewater. In this paper, novel visible-light-responsive nitrogen–sulfur co-doped carbon quantum dots modified ZnO (ZnO/N,S-CQDs) composites with a significantly enhanced photocatalytic degradation performance of Rhodamine B (RhB) were successfully synthesized. Under visible light, the photocatalytic degradation efficiency reached 98.7% over the optimal composite. Besides, the degradation obeyed the pseudo-first-order kinetics model with a photocatalytic rate constant (k) of 0.0473 min−1, which was around 3.71 times higher than that of pure ZnO nanoparticles (0.01273 min−1). In addition, the morphology, size and elemental composition of the ZnO/N,S-CQDs were characterized using TEM, SEM, XRD, FT-IR, and XPS which confirmed the successful synthesis of the composites. Photoluminescence (PL) and transient photocurrent response results indicated an increase in the carrier separation efficiency of ZnO/N,S-CQDs. Based on the active species removal experiment, superoxide radicals (˙O2−) played a leading role in the photocatalytic reactions and a possible photocatalytic degradation mechanism was revealed. These further demonstrate that the N,S-CQDs with varying properties contributed significantly to the enhanced photocatalytic activity of ZnO. Overall, the present method follows the principle of green economy, and novel N,S-CQDs provide a feasible approach for the development of photocatalytic performance of ZnO. [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]

[Display omitted] • A series of novel nanohybrids of g-C 3 N 4 /UiO-66 heterojunctions was synthesized. • The nanohybrids shows excellent activity in photocatalytic degradation of organic dyes. • Degradation rate of the nanohybrids is much faster than g-C 3 N 4 and UiO-66 alone. • The possible photocatalytic mechanism of RhB was proposed and confirmed. • DFT calculations were carried out to confirm the heterojunction structure and photocatalysis mechanism. In this research, a novel composite of typical Zr-based metal–organic frameworks (UiO-66) with porous graphitic carbon nitride (g-C 3 N 4) was prepared by an in-situ preparation method. The g-C 3 N 4 /UiO-66 nanohybrids (CNU-0.5chieved almost 100 % efficiency in the degradation of RhB (60 mg/L, 100 mL) within 70 min under visible light, which was 6.46 and 10.56 times faster than that of pure g-C 3 N 4 and UiO-66, respectively. The improved photocatalytic properties were attributed to the large surface area, enhanced optical adsorption ability and the creation of heterojunction between g-C 3 N 4 and UiO-66. The formation of the heterojunction structure enhanced the photoelectron transfer efficiency and reduced the recombination of electron/hole pairs. Furthermore, the trapping experiments showed that •O 2 –, h+ and •OH were the active species in the photodegradation process, with •O 2 – playing a dominant role. This study offers valuable insights into the preparation of MOF-based photocatalysts with exceptional effectiveness for the removal of contaminants in wastewater treatment. [ABSTRACT FROM AUTHOR]

Wastewater containing organic dyes is harmful to the ecological environment and human health. Graphitic carbon nitride (g-C 3 N 5) is suitable for the photocatalytic degradation of organic dyes, but its photocatalytic activity is low due to several drawbacks. A series of Ag–CeO 2 /g-C 3 N 5 composites with different morphologies of Ag–CeO 2 have been prepared in order to improve the photocatalytic activity of g-C 3 N 5. The photocatalytic activities of the Ag–CeO 2 /g-C 3 N 5 composites were investigated using rhodamine B (RhB) as the target pollutant. When compared with Ag–CeO 2 spheres and g-C 3 N 5 , the charge separation efficiency and photocatalytic activity of the Ag–CeO 2 /g-C 3 N 5 heterostructure were significantly improved. The photodegradation rate of RhB using 50 wt% Ag (1.50)-CeO 2 (sphere)/g-C 3 N 5 was 96.5 %, while pure g-C 3 N 5 and Ag (1.50)-CeO 2 spheres was 30.8 and 9.9 %, respectively. This was attributed to the synergistic effect of the heterojunction comprised of Ag, CeO 2 , and g-C 3 N 5. As an electronic medium, Ag transfers electrons between g-C 3 N 5 and CeO 2 , which can promote electron-hole separation and improve the photocatalytic activity. The 50 wt% Ag (1.50)-CeO 2 (sphere)/g-C 3 N 5 composites also had fair photocatalytic stability and · O 2 − plays a dominant role in the RhB photodegradation process. In addition, the photocatalytic mechanism of 50 wt% Ag (1.50)-CeO 2 (sphere)/g-C 3 N 5 has also been described. [Display omitted] • Series Ag–CeO 2 /g-C 3 N 5 composites were synthesized with respective morphologies of Ag–CeO 2. • Loading Ag–CeO 2 on g-C 3 N 5 can improve the specific surface area and photocatalytic property. • The photodegradation to RhB of 50 wt% Ag–CeO 2 /g-C 3 N 5 composites can reach 96.5 % within 150 min. • The 50 wt% Ag–CeO 2 /g-C 3 N 5 composites have good photocatalytic activity and chemical stability. [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]

Wastewater treatment has become a research hot issue in recent decade. Organic dyes as one of the main pollutants can change the water behavior. To deracinate the organic pollutants from wastewater, there are numerous methods have been taken into consideration. Photocatalysis is the promising strategy for the dye degradation with low cost, high efficiency, and environmental friendliness. Hence, a novel one‐dimensional (1D) magnetic Bi2Fe4O9/C@AgBr composite photocatalyst was prepared employing electrospinning, calcination, and deposition–precipitation methods. The morphology and composition of photocatalyst were characterized, as well as the photocatalytic activities of degrading methylene blue (MB) under visible light were investigated. And the results exhibited that the efficiency of Bi2Fe4O9/C@AgBr under visible light for 60 min is 97.4%. After three cycles, the degradation efficiency of MB could still reach 88.0%. Moreover, radical quenching experiment implicated superoxide radical anions as the primary active species responsible for photodegradation of MB. This work provides a new insight into the design of effective photocatalysts for practical application. [ABSTRACT FROM AUTHOR]

As competitive photocatalysts, Cu 2 O nanoparticles meet with severe photogenerated carries recombination and insufficient light absorption, leading to the poor photocatalytic performance. Herein, the truncated Cu 2 O-Au (CA) binary and Cu 2 O-Au-TiO 2 (CAT) ternary octahedra with Au nanoparticles (Au NPs), preferentially supported on the (110) and (100) planes of Cu 2 O, are synthesized for efficient photocatalytic degradation reactions. The photodegradation rates of MO of CA1 (Cu 2 O-Au containing 1 wt % Au) and CAT are as high as 95.61% and 96.5% under 60 min of visible light irradiation, respectively. On the one hand, the synergistic function of localized surface plasmon resonance (LSPR) of Au NPs and Schottky barrier accelerate the separation and transfer of photogenerated carriers. On the other hand, a Z-scheme electron transfer system is constructed in CAT to promote the photodegradation performance. According to the finite-difference-time-domain (FDTD) simulation result, there is a strong electric field enhancement at the contact sites between Au, Cu 2 O and TiO 2 , which accelerates the electron transfer to a large extent and separates the electron-hole pairs. Therefore, this work may provide an approach for the synthesis and applications of multiple heterostructure catalyst. [ABSTRACT FROM AUTHOR]

In this study, the self-cleaning and photocatalytic properties of clay bricks fired under various temperatures under visible light were addressed. Within this framework, the photocatalytic performance together with adsorbance properties of clay bricks fired at 900 °C, 1000 °C, and 1100 °C were evaluated by means of a UV–vis spectrophotometer. It revealed from the experimental data that fired clay bricks exhibited self-cleaning properties as they were observed to be able to remove the methylene blue (MB) dye as an organic pollutant. The best performance in terms of total degradation efficiency and apparent reaction rate of MB was recorded by the clay brick fired at 900 °C as 90.57% and 0.3039 h−1, respectively. Additionally, it was also confirmed that the physical properties that change with the firing temperature have a great effect on the removal of MB as well as semiconductor content within the brick. [ABSTRACT FROM AUTHOR]

In this work, a highly stable Fe-MOF, namely [Fe2(OH)2(BPTC)]·2DMF·2H2O (JOU-22, H4BPTC = biphenyl-3,3′,4,4′-tetracarboxylic acid, DMF = N,N-dimethylformamide), was solvothermally synthesized using lanthanum nitrate and HF as modulators. Single-crystal diffraction shows that JOU-22 reveals a 3D microporous framework based on Fe–O chains. Due to its high chemical stability, suitable band gap (2.1 eV), and appropriate HOMO (−0.21 V) and LUMO (1.89 V) energy, JOU-22 shows efficient visible-light induced photocatalytic activity for Cr(VI) reduction and dye degradation. JOU-22 can also be used for the degradation of organic dyes, including MB, MO, BG and RhB. Fascinatingly, in the mixed system with the co-existence of dichromate anions and MB, the degradation rate of both Cr(VI) and MB increased significantly due to the synergistic effect between the photocatalytic reduction and oxidation process. This work not only provides a new clue for the preparation of large-size Fe-MOF single crystals, but also enriches the application of Fe-MOFs in the treatment of water pollution. [ABSTRACT FROM AUTHOR]

The layered Bi3O4Br nanoplates were synthesized through a simple calcination process, which can simultaneously harvest visible light and ultrasonic vibration to realize the effective piezo-photocatalysis. The piezo-photocatalysis over the Bi3O4Br leads to a great enhancement in catalytic efficiency with respect to the pure photocatalysis or piezocatalysis. The apparent rate constant of piezo-photocatalysis for the degradation of MO achieves to be 0.008 min − 1 , which is 5.20 and 1.51 times as high as the individual piezocatalysis and photocatalysis, respectively. This enhancement would be attributed to the built-in piezoelectric field induced by ultrasonic vibration facilitating the separation of charge carriers in photoexcited Bi3O4Br. [ABSTRACT FROM AUTHOR]

In the case of wastewater treatment, many researche's are mainly focused on nanopowder-type photocatalysts that have high efficiency because of their good dispersibility and high specific surface area. Ironically, these properties of nanopowder photocatalysts cause some drawbacks in their recovery from treated water, making practical applications in wastewater treatment difficult. The use of a three dimensional based-ceramic fiber as a substrate and graphitic carbon nitride (g-C3N4) as a visible-light-driven photocatalyst can be a promising approach to overcome the above-mentioned limitations. This study describes the immobilization of g-C3N4 on ceramic fiber using a facile co-calcination method and verifies its photodegradation activity under visible light. The recovery efficiency, physicochemical stability of samples, and the potential of the practical application of wastewater treatment were tested with organic dye decomposition experiments under visible light irradiation. [ABSTRACT FROM AUTHOR]

The incorporation of difluoromethylated (CF2) moiety into potentially useful parent molecules lead to significant changes in metabolic stability, lipophilicity, and solubility of the molecules. Over the past several years, with the advent of new difluoromethylating reagents, great progress has been made in the development of a protocol for the direct incorporation of the CF2H group into organic molecules. Among them, difluroalkylation induced by visible light has emerged as an efficient strategy over the past few years. In particular, this protocol provides a more sustainable alternative to other traditional radical‐triggered reactions in terms of environment, energy, step‐economy, health, and safety. The present review mainly focuses on the development of the photocatalytic difluoroalkylation to olefinic moiety using transition‐metal complexes, organic dyes as the photocatalyst; and some organic compounds as a medium of photocatalysis. [ABSTRACT FROM AUTHOR]

In this work, a facial synthesis of α-MoO 3 nanoparticles was done by chemical co-precipitation method. The synthesized α-MoO 3 nanomaterials have been reported for sensing and photocatalysis applications together. For sensing, the α-MoO 3 was coated on FTO based interdigitated electrodes, and the prepared sensor was tested for numerous concentrations of ammonia (100–600 ppm) under different relative humidity levels (11–33%−56–75% −95% RH). The response and recovery time of α-MoO 3 based sensor for 500 ppm of NH 3 were 8 s and 11 s under 95% RH, respectively. The prepared α-MoO 3 based sensor exhibits high selectivity and stability towards ammonia. To analyze the photocatalytic activity of prepared α-MoO 3 nanoparticles, the photodegradation of methylene blue (MB) and methyl orange (MO) under visible light irradiation was studied. The first-order reaction rate constant for MB dye is 0.02434 min−1, and for MO dye is 0.01111 min−1. Finally, the maximum degradation efficiency for MB and MO dyes was calculated to be 95% and 73%, respectively. The given data conclude that the synthesized α-MoO 3 nanoparticles can be used as an effective NH 3 sensor as well as an efficient photocatalyst in organic dye degradation. [Display omitted] • The chemical co-precipitation technique was used to synthesize the hierarchical α-MoO 3 nanoparticles. • The sensor's selectivity, sensitivity, repeatability, and stability towards NH 3 were studied. • The relative humidity enhanced the performance of the NH 3 sensor. • Fast and efficient removal of methylene blue (95%) and methyl orange (73%) were investigated under visible light irradiations. [ABSTRACT FROM AUTHOR]

In this work, a facial synthesis of α-MoO 3 nanoparticles was done by chemical co-precipitation method. The synthesized α-MoO 3 nanomaterials have been reported for sensing and photocatalysis applications together. For sensing, the α-MoO 3 was coated on FTO based interdigitated electrodes, and the prepared sensor was tested for numerous concentrations of ammonia (100–600 ppm) under different relative humidity levels (11–33%−56–75% −95% RH). The response and recovery time of α-MoO 3 based sensor for 500 ppm of NH 3 were 8 s and 11 s under 95% RH, respectively. The prepared α-MoO 3 based sensor exhibits high selectivity and stability towards ammonia. To analyze the photocatalytic activity of prepared α-MoO 3 nanoparticles, the photodegradation of methylene blue (MB) and methyl orange (MO) under visible light irradiation was studied. The first-order reaction rate constant for MB dye is 0.02434 min−1, and for MO dye is 0.01111 min−1. Finally, the maximum degradation efficiency for MB and MO dyes was calculated to be 95% and 73%, respectively. The given data conclude that the synthesized α-MoO 3 nanoparticles can be used as an effective NH 3 sensor as well as an efficient photocatalyst in organic dye degradation. [Display omitted] • The chemical co-precipitation technique was used to synthesize the hierarchical α-MoO 3 nanoparticles. • The sensor's selectivity, sensitivity, repeatability, and stability towards NH 3 were studied. • The relative humidity enhanced the performance of the NH 3 sensor. • Fast and efficient removal of methylene blue (95%) and methyl orange (73%) were investigated under visible light irradiations. [ABSTRACT FROM AUTHOR]

A solvothermal method was used to synthesize the mesoporous TiO 2 , (1-3w %) Cu-doped mesoporous TiO 2 membrane with the help of a bioreactor. To understand the physicochemical composition of all synthesized nanomaterials, the structure, morphology and crystallinity of the materials were studied using X-ray diffractometer (XRD), Field emission scanning electron microscopy (FESEM), Fourier transform-infrared (FTIR), Energy dispersive X-ray spectroscopy (EDS) and cyclic voltammetry (CV). Under artificial light source (500 W mercury bulb) irradiations, the nano catalysts' catalytic effectiveness was examined for the azo dyes, namely Congo red. Cu-doping causes a shift in the light absorption of mTiO 2 from the ultraviolet to the visible region. The 3w% Cu-doped mTiO 2 photocatalyst exhibits lower band gap energy (2.6eV) than TiO 2 which is 3.2 eV to efficiently utilize solar energy. As a result, the light absorption was shifted towards the visible spectrum. The recommended mTiO 2 and (1, 2, 3) w% Cu-doped mTiO 2 photocatalysts were used to photodegrade Congo red and methylene blue. For the degradation of CR, the mTiO 2 photocatalyst exhibited 61% and 3w% Cu-doped mTiO 2 demonstrated 99% photocatalytic performance after 50 min. A variety of scavengers were also utilized to distinguish the active species by catching the radicals and holes created during the process of photocatalytic degradation. CV indicates the presence of Cu2+ and Cu1+ in Cu-doped mTiO 2. Oxygen vacancies and the electronegative surface of Cu1+ seem to perform the photocatalytic reduction of CR. [Display omitted] • Cu-doped mesoporous TiO 2 based membrane using bioreactor. • A novel porous material membrane for Degradation of Dye. • Cu-doped mTiO 2 demonstrated exceptional photocatalytic performance (99%). [ABSTRACT FROM AUTHOR]

[Display omitted] • Flower-like Cu-doped In 2 S 3 was constructed through a one-step hydrothermal method. • Cu-doping enhanced visible-light response and BET surface area of In 2 S 3. • Cu-doped In 2 S 3 exhibited excellent adsorption and catalytic degradation activity of Rhodamine B. • Superoxide ion radical was the main active substance in initiating the degradation of Rhodamine B. In 2 S 3 materials doped with different concentrations of copper ions (Cu-In 2 S 3) were designed and synthesized, which successfully improves the response to visible light, separation of carriers, and adsorption for rhodamine B of In 2 S 3. Cu-doping improves the photocatalytic activity of In 2 S 3 for dye removal. In 2 S 3 doped with 0.3% Cu2+ exhibits the highest photocatalytic activity for the degradation of rhodamine B. In addition, it shows high photocatalytic stability. The photocatalytic active species capture experiments show that the superoxide radical was the main active substance for the photocatalytic degradation of rhodamine B over 0.3% Cu-In 2 S 3. This study provides a valuable reference for the construction of In 2 S 3 -based photocatalytic materials. [ABSTRACT FROM AUTHOR]

Hydrothermally synthesized C-doped K2Al2Ti6O16 (C-KATO) is reported as a novel photocatalysts for methylene blue (MB) and methyl orange (MO) degradation under visible light irradiation. Glucose is used as a carbon source. The structural, morphological, and optical properties are investigated using powder XRD, FE-SEM/EDS elemental mapping, TEM/HR-TEM, FT-IR, UV-Vis DRS, and XPS techniques. C-KATO sample crystallized in the tetragonal lattice with space group I4/m. The bandgap energy of C-KATO is found to be 2.59 eV whereas the bandgap energy of the parent KATO is 3.58 eV. FE-SEM elemental mapping and XPS results of C-KATO reveal the presence of carbon in the KATO lattice. The photocatalytic activities of the KATO and C-KATO oxides are evaluated for MB and MO degradation under visible light irradiation, and the results have been compared with those attained over P25 Degussa. It shows higher activity in comparison to P25. The mechanistic dye degradation pathway is studied using radical scavengers during photoreaction. [ABSTRACT FROM AUTHOR]

• Novel TiO 2 QDs/BiOBr/BiOCl nanocomposites as efficient photocatalysts are reported. • The TiO 2 QDs/BiOBr/BiOCl (30%) nanocomposite exhibited the highest activity. • Activity was 176-folds greater than TiO 2 in RhB degradation under visible light. • The nanocomposite displayed substantial activity in removal of different pollutants. BiOBr and BiOCl were decorated on TiO 2 QDs through n-p-p heterojunctions by a simple strategy and they were applied for degradation of three organic dyes upon visible illumination. The obtained photocatalysts were analyzed via XRD, FESEM, EDX, UV–vis DRS, PL, BET, TEM, HRTEM, FT-IR, EIS, XPS, and transient photocurrent measurements. The TiO 2 QDs/BiOBr/BiOCl nanocomposite with 20% wt. of BiOBr and 30% wt. of BiOCl displayed superior photoability in the degradation of methylene blue, rhodamine B, and fuchsine, which was almost 34.5, 176, and 78.7-times larger than TiO 2 and 27.8, 13.5, and 51.5-folds greater than TiO 2 QDs, respectively. The results show that the construction of intimate n-p-p heterojunctions between BiOBr, TiO 2 QDs, and BiOCl counterparts leads to enhanced visible-light harvesting and improved charge separation, resulted efficiently increased photocatalytic activity. The trapping results proved that h+, •O 2 −, and OH• species have considerable effects on the degradation reaction. We think that the improved efficiency of the ternary TiO 2 QDS/BiOBr/BiOCl photocatalyst is a splendid alternative for the removal of toxic contaminants from wastewater. [ABSTRACT FROM AUTHOR]

Photocatalysis technology has risen to effectively degrade the hardly-degraded organic pollutants in recent years and the photocatalysts play an important role in striding the obstacles of the visible light response. Herein, a high-efficiency BiVO4/Bi5O7I heterojunctional photocatalysts have been purposefully designed by controlling the reactant ratios and ultrasonic time of reaction at room temperature. Photocatalytic experimentals confirm that the prepared optimal BiVO4/Bi5O7I composites displayed enhanced photocatalytic ability to degrade rhodamine B and quinoline blue under visible light irradiation. Furthermore, the photocatalysts exhibits high photostability and reusability proved by four consecutive cycling experiments. A possible mechanism of p–n heterojunctional BiVO4/Bi5O7I composites enhanced the photocatalytic performance was discussed in detail on the basis of the reactive species trapping experiments in photocatalytic degradation process. [ABSTRACT FROM AUTHOR]

The present work examines binary solid solutions of Bi x Sb 2-x S 3 [x = 0.536, 1.09, 1.68] toward photocatalytic degradation of Rhodamine-B (RhB) under visible light. Phase and microstructural analysis confirmed the formation of Bi 0.536 Sb 1.464 S 3 , Bi 1.09 Sb 0.91 S 3 , and Bi 1.68 Sb 0.32 S 3 solid-solution phase with nanorods (~25–50 nm average diameter) morphology. The synthesized products show outstanding photocatalytic degradation of RhB with ~95–99.5% degradation achieved within 30 min. The kinetic study finds the high degradation efficiency (~98%) of Bi x Sb 2-x S 3 photocatalysts stems from the amenable band gap (~2.3 eV, confirmed from DRS study), and higher separation efficiency of photogenerated electron-hole pairs (established from PL studies). The complete detoxification of RhB dye was confirmed by quantitative estimation of CO 2 post photodegradation through GC analysis. Moreover, due to the solid and hard nature of the photocatalysts, it was easily recovered from the reaction mixture and reused multiple times without losing the degradation behavior. The parallel comparison with other active photocatalysts demonstrates Bi x Sb 2-x S 3 [x = 0.536, 1.09, 1.68] have higher catalytic efficiency with similar dosing hitherto reported in the literature and possibly can be used for degradation of other organic dyes using the visible spectrum. [ABSTRACT FROM AUTHOR]

Semiconductor photocatalysts has become one of the most attractive technologies in the field of environmental remediation. Titanium dioxide (TiO2) is widely concerned due to the potential applications in the degradation of organic dyes. Nonetheless, the inherent wide band gap of TiO2 has been proved to restrict the photocatalytic activation under visible light, and a variety of strategies have been attempted to develop TiO2 composite catalysts with short band gap compositions, such as carbonaceous nanomaterials. In the recent progress, the present review attaches more importance to the unique morphology and fickle structure of carbonaceous–TiO2 photocatalysts, among which there are sandwich-like structure, foam-like structure, core–shell structure, nanotube, nanorod structure, semi-wrapped structure, etc., and all of them have been demonstrated in this paper. Furthermore, reviews of the enhanced mechanisms, synthesis method and performance comparison of carbonaceous–TiO2 photocatalysts reported in the literature are also suggested and conducted. In brief, this work provides some novel insights for the preparation of TiO2 composites as photocatalysts with excellent performance and contributes to promoting their application in environmental protection issues. [ABSTRACT FROM AUTHOR]

• Prepared composite nanofiber membrane possesses a good photocatalyst performance. • High degradation activity of organic dyes under visible light. • The composite nanofibers membrane possessed excellent recovery and reuse. • The free-standing membrane is flexible and easy to handle. • The flexibility of the composite nanofibers allows use in a continuous operation. This study proposed an effective method by using photocatalytic composite nanofiber membranes in order to degrade malachite green (MG) and acid red 27 (AR 27) to harmless products. The photocatalytic composite nanofiber membrane, Polyacrylonitrile (PAN) was incorporated with catalyst SiO 2 and TiO 2 photocatalyst. The PAN/SiO 2 -TiO 2 -NH 2 nanofiber membrane was synthesized by electrospinning technique followed by chemical crosslinking. The results of SEM, EDX, FTIR and XRD confirmed the successful preparation of nanofiber membrane. XRD analysis shows the confirmation of SiO 2 and TiO 2 peaks. The result shows that PAN/SiO 2 -TiO 2 -NH 2 nanofiber membrane exhibit the highest degradation with a good distribution of SiO 2 and TiO 2 on the PAN nanofiber membrane surface. The results showed that the complete photodegradation of MG and AR 27 with artificial visible-light was achieved after 9 and 25 min, respectively. In addition, the nanofiber membrane exhibited good stability and reusability for MG and AR 27 photodegradation and has potential to be applied in industrial application. [ABSTRACT FROM AUTHOR]

Visible-light-driven organic photochemical reactions have attracted substantial attention from the synthetic community. Typically, catalytic quantities of photosensitizers, such as transition metal complexes, organic dyes, or inorganic semiconductors, are necessary to absorb visible light and trigger subsequent organic transformations. Recently, in contrast to these photocatalytic processes, a variety of photocatalyst-free organic photochemical transformations have been exploited for the efficient formation of carbon–carbon and carbon–heteroatom bonds. In addition to not requiring additional photocatalysts, they employ low-energy visible light irradiation, have mild reaction conditions, and enable broad substrate diversity and functional group tolerance. This review will focus on a summary of representative work in this field in terms of different photoexcitation modes. 1 Introduction 2 Visible Light Photoexcitation of a Single Substrate 3 Visible Light Photoexcitation of Reaction Intermediates 4 Visible Light Photoexcitation of EDA Complexes between Substrates 5 Visible Light Photoexcitation of EDA Complexes between Substrates and Reaction Intermediates 6 Visible Light Photoexcitation of Products 7 Conclusion and Outlook [ABSTRACT FROM AUTHOR]

• A 2D covalent organic framework Por-PD-COF as selective adsorbent and photocatalyst was designed and synthesized. • Por-PD-COF could selectively and competitively adsorb MB from the mixed organic dyes aqueous solution. • Por-PD-COF could photodegrade MB effectively under visible light. • Por-PD-COF can be recycled and reused after absorption or photocatalysis. In this work, amide bonds linked 2D porphyrin-based covalent organic framework (Por-PD-COF) was designed and synthesized through condensation reaction between meso -tetrakis (p -carboxyphenyl) porphyrin (TCPP) and para -phenylenediamine (PD). Large surface area, abundant active sites and good stability of Por-PD-COF made it can quickly and efficiently absorb methylene blue (MB) selectively and remove it from aqueous solution. More importantly, in different mixture of organic dyes including RhB and MB, MB and MO, Por-PD-COF can selectively adsorb MB with a large adsorption capacity (328.57 mg·g−1), while a little MO and hardly RhB because of the unique charge selectivity and specific pore size. Especially in the mixture solution of MO and MB, compatitive adsorption appeared, MB can substitute the adsorbed MO on the active sites in the channel of Por-PD-COF. Furthermore, with the band gap narrow to 1.02 eV, Por-PD-COF could be used as efficient photocatalyst to degrade MB (99%, 180 min) directly under visible light irradiation, and can be reused for four times with almost no absorptive and photocatalytic capacity losing. The possible adsorption and photocatalytic mechanisms of Por-PD-COF were also proposed. As a result, with the uncomplicated preparation, effective and selective adsorption and reusability, Por-PD-COF was a promising specific adsorbent and photocatalyst for further application in specific organic molecules separation and organic waste removal from aqueous solution. [ABSTRACT FROM AUTHOR]

Abstract Here we propose new type II semiconducting nanocomposite TiO 2 /CoSe for effective separation of the photo-induced charges, thus enhancing the visible light harvesting capability of TiO 2. The formation of TiO 2 /CoSe nanocomposite is confirmed by XRD, FE-SEM, HR-TEM, XPS and BET characterization techniques. Remarkable results were obtained during photodegradation study of both Rhodamine B (99.86%) and methylene blue (97.85%) within just 90 min of visible light irradiation. The mechanistic investigation demonstrates that the Superoxide (O 2 −) radicals are most reactive species participates in photocatalytic dye degradation. The synthesized photocatalyst has good reusability, it can be successfully reused for six batches of photocatalytic reactions. Graphical abstract Unlabelled Image Highlights • Rutile TiO 2 nanorods decorated with CoSe nanoparticles. • TiO 2 /CoSe nanocomposite: a visible light harvesting type II semiconductor • Enhanced photocatalytic efficiency is attributed to the retarded rate of recombination of photoexcitons. • Superoxide radical is most reactive species responsible for the photodegradation. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Vanadium oxide improved the photocatalytic activity of four different supports. • Brønsted acid sites concentration on V 2 O 5 /ZM5 and V 2 O 5 /TiO 2 is higher than V 2 O 5 /SBA. • Remarkable photocatalytic activity was observed on V 2 O 5 /ZM5 under visible light. • V4+ species and Brønsted acid sites improved the photocatalytic degradation of Eosin Y. • V 2 O 5 supported on TiO 2 and zeolite ZM5 are highly efficient to eliminate organic dye pollutants. Abstract SBA, zeolite-ZM5, TiO 2 and P25, used as dispersant agents of vanadium oxide, were synthesized. The supports (SBA, Zeolite-ZM5, TiO 2 and P25) were loaded with 3 wt.% of V 2 O 5. V 2 O 5 /ZM5, V 2 O 5 /P25 and V 2 O 5 /TiO 2 showed high photocatalytic activity for the degradation of Eosin Y employing a visible light source (450 nm). The photocatalysts were characterized by X-ray diffraction, XPS, UV-vis, S BET , SEM, TEM, and FTIR (surface acidity). Under visible light, the photocatalytic degradation rate displayed the following order V 2 O 5 /TiO 2 (93%) > V 2 O 5 /P25 (81%) > V 2 O 5 /ZM5 (70%) > V 2 O 5 /SBA (55%). This behavior is in conjunction attributable to the oxidation state of the vanadium species V4+ and the presence of Brønsted acid sites. The structure and properties of the TiO 2 play an important role during the photodegradation of the Eosin Y. Results here obtained give new insights for the water treatment processes using visible light over vanadium photocatalysts. [ABSTRACT FROM AUTHOR]

Abstract Photocatalysis, a green technique is widely applied in the fields of environmental remediation for the removal of many pollutant constituents. It is known that major problems related to the present photocatalytic system, which significantly limit their photocatalysis efficiency, are low-usage of visible light, fast recombination and also the low migration ability of the photo-generated electrons and holes. To solve the problem associated with conventional photocatalytic systems, recently hybrid photocatalysts containing carbon quantum dots (CQDs) have been proposed. The tunable photocatalytic characteristics of CQDs are widely mentioned. Moreover, the excellent photocatalytic activity of CQDs alone and in combination with photoactive species in the photo-degradation of organic pollutants was confirmed in the many reports. This work presents a comprehensive view of the application of CQDs to improve conventional photocatalytic systems in those studies which considered organic dyes as sample pollutants. In addition to providing detailed information regarding important roles of CQDs in photocatalytic activity enhancement, this review provides the comprehensive details about findings of the photocatalytic degradation of dyes using CQD-based photocatalysts and the best CQD-based composites photocatalysts are highlighted. Highlights • Combination of CQDs/conventional photo-catalysis systems improved their performance. • Multifunctional roles of CQD in photo-catalysis ate extensively elucidated. • CQD-based photo-catalysis degradation of organic dyes is comprehensively reviewed. [ABSTRACT FROM AUTHOR]

In this study, a novel nanostructure of amorphous MoSe x was produced by a facile low-temperature hydrothermal method. Better adsorption and photodegradation of rhodamine B (RhB) and methylene blue (MB) were achieved with amorphous MoSe x than with crystalline MoSe x under dark conditions and visible light irradiation. More importantly, the catalytic mechanisms of the amorphous and crystalline samples were compared by free radical-trapping experiments. The results showed that the main active substance that increased the photocatalytic activity in amorphous MoSe x was superoxide radicals ( O 2 − ), whereas the main active substances for crystalline MoSe x were holes (h + ) and hydroxyl radicals ( OH). In addition, amorphous MoSe x had more unsaturated atoms and a greater specific surface area because of its unique amorphous structure, thus enhancing its photocatalytic performance and adsorption capacity. The study of amorphous molybdenum selenide provides a new idea for improving the photocatalytic activity of two-dimensional materials, which is of great significance. [ABSTRACT FROM AUTHOR]

In this study, we synthesized a novel LaFeO 3 /AgBr heterojunction via an in-situ precipitation method. The composition, structure, and optical absorption properties of LaFeO 3 /AgBr were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and ultraviolet-visible diffuse reflectance spectroscopy. The photocatalytic activity of the LaFeO 3 /AgBr photocatalyst was determined based on the degradation of tetracycline and three types of dyes comprising methyl orange, rhodamine B (RhB), and malachite green. The photocatalytic performance of the LaFeO 3 /AgBr heterojunction was much better compared with that of the pure AgBr and LaFeO 3 . It should be noted that Ag nanoparticles were not present in the fresh LaFeO 3 /AgBr heterojunction. However, according to the XRD and TEM results obtained for 10%-LaFeO 3 /AgBr, Ag nanoparticles were generated in the LaFeO 3 /AgBr heterojunction during the photodegradation process, which accelerated the separation of photoinduced carriers in the LaFeO 3 /Ag/AgBr system. Based on the detection of active species, we propose a Z-scheme photocatalytic and organic dye (RhB) photosensitization mechanism, which also considers the role of Ag nanoparticles in the separation of electrons and holes. The stability of the LaFeO 3 /AgBr heterojunction was also investigated, which showed that the incorporation of LaFeO 3 remarkably improved the photocatalytic activity as well as enhancing the stability of the LaFeO 3 /AgBr heterojunction by suppressing the photodecomposition of AgBr. [ABSTRACT FROM AUTHOR]

A novel visible-light-responsive Ag 3 PO 4 /diatomite composite is successfully prepared by ultrasound assisted precipitation method. The structure and properties of Ag 3 PO 4 /diatomite composite are characterized by X-ray diffraction (XRD), fourier transform infrared spectrometer (FT-IR), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), high resolution transmission electron microscope (HRTEM), N 2 adsorption/desorption, X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectra (UV–vis DRS) and photoluminescence (PL). The obtained Ag 3 PO 4 /diatomite composites show enhanced photocatalytic performance for the degradation of acid brilliant scarlet dye compared with pure Ag 3 PO 4 under visible light irradiation, and the 10%-Ag 3 PO 4 /diatomite composite exhibits the optimum photocatalytic degradation efficiency when the initial concentration of acid brilliant scarlet dye is 50 mg/L with the pH 6 and the catalyst dosage is 1 g/L, which is approximately 3.6 times higher than that of pure Ag 3 PO 4 . Meanwhile, it shows the better stability after three cycles. The enhanced performance can be attributed to the uniform dispersion of Ag 3 PO 4 on the surface of diatomite, the stable structure, the enlarged specific surface area and the high-efficiency separation of photogenerated electron-hole pairs. Furthermore, the free radical trapping experiments indicate that h + and •O 2 – are the major active species in the photodegradation process of acid brilliant scarlet dye. This work has the potential to provide a high-efficiency and cost-effective photocatalyst for the degradation of dye pollutants. [ABSTRACT FROM AUTHOR]

In this research successfully synthesized a novel heterojunction of MoS 2 and α-Fe 2 O 3 by hydrothermal method with special adjustments to the nanostructure for photocatalytic and photoelectrochemical (PEC) performance. The nano MoS 2 /α-Fe 2 O 3 (nano MF) has an excellent surface area and great intrinsic edges, which can produce more active reaction sites. The advantage of this nanocomposite has certified by spectroscopic and characterizations approach. The results presented that for methylene blue (MB), nano MF photocatalysts revealed rather improved photocatalytic capability (∼98.5%) and the optimal transient photocurrent density (∼0.45 μA/cm2) with visible-light irradiation. These two analyses were three and nine folds larger than those displayed by the Fe 2 O 3 sample, respectively. The photocatalytic degradation performance of nano-heterojunction photocatalysts improved due to increase reactive sites of the photocatalyst and reduced recombination of photo-induced carriers. The results reveal that the formation of a strong heterojunction between two semiconductors leads to the formation of the active photocatalyst. In this system, the generated superoxide radicals, holes and hydroxyl radicals with potential oxidation were operated to obtain superior efficient photodegradation of organic dyes. The fabricated nano MF samples indicated good stability, high reusability and wide utilization potential in photocatalytic and PEC processes. The present work has demonstrated the promising potential of nanocomposites for efficient photoelectrochemical and environmental remediation. [Display omitted] • Nano heterostructures MoS 2 /α-Fe 2 O 3 exhibited favorable photocatalytic degradation of MB solution. • Nano heterostructures presented a much better performance in photoelectrochemical activities than MoS 2 and α-Fe 2 O 3. • Nano heterostructures revealed excellent photocatalytic reusability and stability. • Nano MoS 2 /α-Fe 2 O 3 photoanode improves the photoelectrochemical performance. [ABSTRACT FROM AUTHOR]

The present research investigates the photocatalytic activity of pyrrole and polypyrrole (PPy) under visible light for the treatment of contaminated water with the organic dye methylene blue (MB). Pyrrole is inert for photo-catalytic activities, because of its large HOMO-LUMO gap. However, when PPy was synthesized, the electronic structure changes, making PPy an active photo-catalyst. PPy can be utilized to produce photo-excited charges on any type of light source (UV or visible) since it has broad absorbance spectra. The UV-Vis spectroscopy shows absorbance bands in the UV and visible region, which correspond to absorption maxima at 380 nm, 470 nm and 525 nm. Additionally, a broad tail near the IR region was observed which corresponds to polaronic and bipolaronic transitions. These charges actively contribute to the breakdown of dye during the degradation phenomenon. The presence of polaron was confirmed by electron spin resonance (ESR) having g value of 1.99, and its intensity decreases on light exposure. The interaction between PPy and MB through polaron-bipolaron was explained by Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). N 1s and C 1s XPS results show the shift in the B.E. of –N–H+·, =N–H+, –C N+ and =C–N+·when PPy interacts with MB which gives the signature of charge transfer. Furthermore, the interactions within the system were analyzed by ultraviolet photoelectron spectroscopy (UPS) data which provided descriptive information on the molecular orbital level and also gave an indication of charge transfer state formation between PPy and MB at − 7.83 eV. [Display omitted] • Photocatalytic activity of pyrrole and PPy nanoparticles with methylene blue under visible light. • By introducing polaronic-bipolaronic levels within HOMO-LUMO gap of PPy, increases its absorption efficiency in vis-range. • Polarons-bipolarons are interacting charge mediators among PPy and MB, contributing to dye degradation. • Molecular orbital interaction between PPy and MB has been explained by UV photoelectron spectroscopy. [ABSTRACT FROM AUTHOR]