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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]

The novel GdTaO 4 phase exhibits good photocatalytic activity under visible light irradiation and holds great promise for the removal of organic dyes from industrial wastes. The GdTaO 4 samples were synthesized using the hydrothermal and calcination process with different weight ratios of gadolinium nitrate hydrate (G) and tantalum pentachloride (T), and their structural studies confirmed the formation of the GdTaO 4 (GT) phase. Among the samples, GT-4 (with a weight ratio of 4:1) exhibited the highest photocatalytic activity for the degradation of Methyl Orange (MO) dye under visible light irradiation. To enhance the photocatalytic performance, H 2 O 2 was used as a green additive, and the photocatalytic abilities were examined by varying dye types and concentrations. X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS) revealed the local atomic and electronic structures around Ta and Gd and highlighted the contribution of Gd3+ to the GT system, which is a crucial factor in supporting the enhanced photocatalytic performance. Moreover, in-situ XAS at Gd M 5 -edge and O K-edge were examined under illumination/dark conditions to explore the electronic structures of photo-excited electron transition in the photocatalytic process. The analytical results provided strong evidence correlating the electronic structure and photocatalytic property of the GT. This study demonstrates that GdTaO 4 exhibits good photocatalytic activity under visible light irradiation, making it a promising new Ta-based photocatalyst for the effective removal of organic dyes from industrial wastes. [Display omitted] • GdTaO 4 photocatalysts are synthesized via hydrothermal and calcination processes with different Gd and Ta ratios. • Photocatalyst GT-4 exhibited the highest catalytic activity for MO degradation under visible light. • To enhance the Photocatalytic performance, H 2 O 2 was used as a green additive, assessing dye types and concentrations. • Ex-situ and in-situ XAS are crucial for understanding enhanced photocatalytic performance by revealing Ta and Gd local atomic/electronic structures. [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]

Methylene blue (MB) and hexavalent chromium(Cr(VI)) are hazardous pollutants in textile waste and cannot be completely removed using conventional methods. So far, there have been no specific studies examining the synthesis and activity of N–TiO 2 /rGO as a photocatalyst for removing MB and Cr(VI) from textile wastewater. This work especially highlights the synthesis of N–TiO 2 /rGO as a photocatalyst which exhibits a wider range of light absorption and is highly effective for simultaneous removal of MB-Cr(VI) under visible light. Titanium tetrachloride (TiCl 4) was used as the precursor for N–TiO 2 synthesis using the sol-gel method. Graphite was oxidized using Hummer's method and reduced with hydrazine to produce rGO. N–TiO 2 /rGO was synthesized using a hydrothermal process and then analyzed using several characterization instruments. The X-ray diffraction pattern (XRD) showed that the anatase N–TiO 2 /rGO phase was detected at the diffraction peak of 2θ = 25.61. Scanning electron microscopy and transmission electron microscopy (SEM-EDS and TEM) dispersive X-ray spectrometry images show that N–TiO 2 particles adhere to the surface of rGO with uniform size and N and Ti elements are present in the N–TiO 2 /rGO combined investigated. Gas absorption analysis data (GSA) shows that N–TiO 2 /rGO had a surface area of 77.449 m2/g, a pore volume of 0.335 cc/g, and a pore size of 8.655 nm. The thermogravimetric differential thermal analysis (TG-DTA) curve showed the anatase phase at 500–780 °C with a weight loss of 0.85%. The N–TiO 2 /rGO composite showed a good photocatalyst application. The photocatalytic activity of N–TiO 2 /rGO for textile wastewater treatment under visible light showed higher effectiveness than ultraviolet light, with 97.92% for MB and 97.48% for Cr(VI). Combining N–TiO 2 with rGO is proven to increase the light coverage in the visible light region. Removal of MB and Cr(VI) can be carried out simultaneously and results in a removal efficiency of 95.96%. Proposed schematic illustration mechanism for the removal of MB-Cr(VI) over N–TiO 2 /rGO. [Display omitted] • Synthesis of N–TiO 2 /rGO as simultaneous photocatalyst for the removal of MB-Cr(VI). • N–TiO 2 /rGO showed a wider light absorption range for textile wastewater treatment. • N–TiO 2 /rGO exhibited highly effective for removal of MB-Cr(VI) under visible light. [ABSTRACT FROM AUTHOR]

Photodegradation of organic pollutants using metal oxides has shown extraordinary promise owing to the catalytic efficacy, low cost, less noxiousness, and good chemical constancy. In this research, pure and transition metal ions (Cu)-doped V 2 O 5 nanosheets were synthesized and investigated for their photocatalytic efficiency using methyl blue (MB) and rhodamine B (RhB) organic dye pollutants under visible light irradiation. The orthorhombic crystal phase was confirmed by XRD analysis, which exhibited a stable phase upon incorporating Cu dopant ions. Optical properties were examined using optical absorption spectroscopy, while a reduced band gap was observed in the doped V 2 O 5 nanosheets over the undoped sample. EIS analysis confirmed lower charge resistance in doped V 2 O 5 nanosheets. The Cu dopant incorporation into the host matrix considerably enhanced photodegradation efficiency for MB and RhB impurities under light illumination. The improvement in catalytic efficacy is attributed to dopant ions that can separate photoinduced charge carriers and the quick movement of the charge. Moreover, comparatively lesser crystalline size, improved specific surface area, and hydroxyl group onto the catalyst surface are quite advantageous to offer better photocatalytic activity of Cu-doped V 2 O 5 nanosheets. [Display omitted] • Pure and Cu-doped V 2 O 5 nanosheets were synthesized using hydrothermal method. • XRD analysis confirmed orthorhombic crystal phase of synthesized materials. • Photodegradation of MB and RhB pollutants were examined under visible light. • Doped V 2 O 5 catalyst shows 95.4% and 91.2% degradation of MB and RhB. • · O 2 −, OH · species played a major contribution in the removal toxic pollutants. [ABSTRACT FROM AUTHOR]

Among the important needs of human societies is the elimination of environmental pollution and also the construction of high-performance and inexpensive biosensors. In this regard, the construction of multi-functional composites has been considered. A novel magnetic graphite carbon nitride decorated by tri-vanadium substituted Dawson-type heteropolytungstate nanocomposite (C 3 N 4 /Fe 3 O 4 @P 2 W 15 V 3) effectively synthesized and characterized by prevalent functional analysis. The prepared nano-catalyst presents bi-functional usage involving photocatalytic removal of dyes (methylene blue, congo red and phenyl red) (around 98%) under visible light radiation and greatly sensitive colorimetric sensing of cysteine in an aqueous media. Moreover, synthesized nano-catalyst successfully recovered five times without any considerable deficiency on its photocatalytic ability. Further, Moreover, we propose a novel method for cysteine detection based on the C 3 N 4 /Fe 3 O 4 @P 2 W 15 V 3 nanocomposite. This nanocomposite displayed a privileged catalytic feature for cysteine oxidation to extend a clock reaction of methylene blue as an indicator in the presence of NaBH 4 in acidic solution. More importantly, this colorimetric sensing method of cysteine presents an easy, low-cost, selective, and rapid colorimetric assay with a detection limit value of 7.2 μM in the acceptable linear range of 5–600 μM. [Display omitted] • The Preparation and characterization of a novel and green photocatalyst abbreviated g-C 3 N 4 /Fe 3 O 4 @P 2 W 15 V 3. • The g-C 3 N 4 /Fe 3 O 4 @P 2 W 15 V 3 has been used for the degradation of organic dyes. • The g-C 3 N 4 /Fe 3 O 4 @P 2 W 15 V 3 photocatalyst exhibits great recovery ability and photodegradation activity than pristine g-C 3 N 4. • Efficient colorimetric sensing of Cys with g-C 3 N 4 /Fe 3 O 4 @P 2 W 15 V 3 system. [ABSTRACT FROM AUTHOR]

The further development of an efficient and sustainable water treatment requires the development of a very active and controllable photocatalyst. The heterojunction is a promising site where the activity of such a photocatalyst can be enhanced. Organic dyes have become a severe concern in recent years owing to their significant presence in wastewater. Hexavalent Chromium (Cr (VI)) is a potential carcinogen also exhibiting great persistence in wastewater. So, a low-waste, high-performance materials is required to eliminate organic dyes and Cr (VI) from wastewater. In this study, CNO/g-CN (CuNb 2 O 6 /g-C 3 N 4) photocatalyst synthesized via co-precipitation, followed by calcination which were characterized using physiochemical and photo-electrochemical approaches to identify their structural, photochemical and optical traits. The uniqueness of the synthesized photocatalyst is due to both its efficient photo-reduction of Cr (VI) and photo-degradation of Rhodamine B (RhB), Methylene Blue (MB) and Methyl Orange (MO) under visible light. The CNO/g-CN composite with 30% CNO heterojunctions exhibited the highest photocatalytic activity with Cr (VI) 92.80% photoreduction and efficiency degradation for RhB, MB, MO of 99.6%, 98.50%, 99.0%, respectively, with constant rate (k). This efficient photocatalytic activity is attributed to the lower recombination rate of electron-hole pairs. Free radical trapping experiments showed that •O 2 − and h+ play an important role in the photodegradation. The study, therefore, opens an alternative route in the synthesis of very efficient binary photocatalysts for application in environmental remediation. [Display omitted] • A novel synthesis of the photocatalytic active composite CuNb 2 O 6 /g-C 3 N 4 is reported. • The 30% CNO/g-C 3 N 4 heterojunction exhibited significant photocatalytic activity. • The photo-catalyst degraded all the dyes over 99% and Cr (VI) to 93% took place. • Two active species, ⁰O 2 − and h⁺ are responsible for the photocatalytic activity. [ABSTRACT FROM AUTHOR]

The present study describes the enhanced photodegradation of organic pollutant dyes, congo red (CR) and rhodamine B (RhB) dyes under visible light irradiation. AgIO 4 nanorods decorated on Bi 2 S 3 nanoflakes in various proportions were synthesized via sono-chemical route wherein the deposition of varying amounts of AgIO 4 on Bi 2 S 3 plays a pivotal role in improving the photodegradation ability. The characterization of the as-synthesized nanohybrids was assessed by XRD, UV–vis DRS, PL, EIS, ESR, FT-IR, XPS, HR-TEM, FE-SEM, N 2 adsorption and desorption techniques. The effect of initial CR and RhB dye concentration, reaction pH and usage of nanohybrid concentration were investigated where 30%-AgIO 4 /Bi 2 S 3 exhibited excellent visible light photodegradation of 95.58% for CR and 96.11% for RhB dyes at 140 min and 100 min respectively. The superoxide (•O2−) and hydroxyl radicals (•OH) played predominant role in the photodegradation of CR and RhB which is experimentally confirmed by radical trapping experiments. Also, the photocatalysts exhibited good photo stability and excellent reusability. The TOC analysis confirmed the complete mineralization of CR and RhB dyes by the nanohybrid and the formation of possible intermediate and degradation pathway was delineated based on GC/MS analysis. The outstanding photodegradation performance were ascribed to the Z-scheme charge transfer path, which effectively promotes the separation and transfer of e−/h+ pairs, resulting in a strong redox activity of the accumulated charge to decompose organic dyes during the degradation reaction. The study suggested that the nanohybrid can be utilized for the removal of organic pollutants from the contaminated water bodies. [Display omitted] • AgIO 4 nanorods decorated Bi 2 S 3 nanoflakes synthesized via sono-chemical route. • An excellent photodegradation was exhibited by the prepared samples. • The photocatalyst shows great structural stability and excellent cycling ability. • Hydroxyl radicals and superoxide radicals plays a vital role in photodegradation. [ABSTRACT FROM AUTHOR]

The release of dyes-loaded wastewater from various industries is a major threat to human beings due to their health hazard effects. Ternary ferrites-based visible light photocatalyst Fe 2 Zn 0.5 Cu 0.5 O 4 -CM (CZF-CM) was formed via the co-precipitation method. These prepared ternary ferrites nanoparticles Fe 2 Zn 0.5 Cu 0.5 O 4 (CZF-NPs) and photocatalyst (CZF-CM) were analyzed using different spectroscopic techniques. The average crystallite size of CZF-NPs was calculated from XRD data using Scherer's equation and found to be 12 nm. The elemental composition of the synthesized ternary ferrites nanoparticles (CZF-NPs) was defined by the EDX images. The morphology of CZF-CM photocatalyst is spherical, having a smooth surface and average microspheres size of 810 μm based on SEM micrographs. The photocatalyst has bandgap of 2.57 eV, which lies in the visible range of the electromagnetic spectrum derived by extrapolating Tauc's plot. Photocatalyst CZF-CM showed 94% degradation efficiency for Rhodamine B (RB) dye at optimized conditions of initial dye concentration, catalyst dosage, pH and sunlight irradiation contact time as 40 ppm, 0.7 g, pH 8 and 125 min, respectively. Maximum degradation (96%) of methyl orange (MO) dye occurred at pH 6, at similar optimized conditions as the RB dye. The binary ferrites photocatalyst Fe 2 CuO 4 -CM (CF-CM) and Fe 2 ZnO 4 -CM (ZF-CM) of the selected metals showed lesser photocatalytic efficiency than ternary ferrites. An artificial neural network in addition to the response surface methodology was used for the optimization process. The artificial neural network is highly in agreement with the experimental results obtained for the selected dyes. The corresponding predicted response for each data set from ANOVA showed high R2, R2 adj, and R2 pred values for the proposed model. It also indicates that contributing parameters in the model are significant due to having very high F-values and low p-values. It is concluded that the synthesized photocatalysts are considered an efficient entrant for the decolorization of industrial wastewater. [Display omitted] • Development of ternary-based visible light nanophotocatalyst Fe 2 Zn 0.5 Cu 0.5 O 4 -CM. • Structural and morphological characteristics were scrutinized using advanced techniques. • Highly efficient photocatalytic degradation of organic dyes under sunlight irradiation. • Response surface methodology and artificial neural network for optimizing operating factors. [ABSTRACT FROM AUTHOR]

Wastewater treatment is the most serious problem in this upcoming era. A harmful effluent like organic dyes, heavy metals, acids from industries mixed in wastewater is deteriorating the environment. To get rid of these poisonous materials and to recycle wastewater for domestic purposes, there are many steps which included photocatalytic dye degradation. PVP assisted Mn–CdS nanoparticles was prepared by novel hydrothermal technique. The characteristic behavior of pure and PVP (1% and 2%) assisted Mn–CdS samples were studied by further analysis. The structural, optical, vibrational, morphological, chemical composition behavior of synthesized pristine and surfactant induced Mn–CdS nanoparticles were analyzed. UV–Vis spectra revealed the optical behavior of the prepared pure and PVP (1% and 2%) assisted Mn–CdS samples. The bandgap obtained was 2.2, 2.06 and 1.99 eV for pure Mn–CdS, 1% PVP-Mn-CdS and 2% PVP- Mn-CdS. The narrow bandgap is one of the advantage of the material. Mn–CdS, 1% PVP-(Mn–CdS) and 2% PVP- (Mn–CdS) morphology were further investigated by Scanning Electron Microscopic studies (SEM). The surfactant (PVP) was added to enhance the morphology development and decrease agglomeration on the surface and the SEM images revealed a clear evidence for enhancement of morphology in all three samples. 2% PVP-(Mn–CdS) sample showed a good development in morphology when compared with other two samples and the best sample showed formation of nanorods below the surface of nanoparticles. Further, Mn–CdS, 1% PVP-(Mn–CdS) and 2% PVP- (Mn–CdS) was indulged to investigate the cationic degradation. The photocatalytic activities of three samples were carried out with loading different amount of the catalysts and 30 mg catalyst 2% PVP- (Mn–CdS) loaded dye solution showed a considerable degradation of methylene blue dye. The 30 mg catalyst (2% PVP-Mn-CdS) showed 98% efficiency under visible light irradiation for about 2 h. The best candidate, 30 mg catalyst (2% PVP-Mn-CdS) investigated for its reusability. The catalyst showed almost 98% of efficiency up to three cycles which confirmed the level of potential of the sample. 2% PVP-(Mn–CdS) sample would be promising candidate in wastewater treatment. It can be further utilized for removing dyes from wastewater in wastewater remediation process. • 2% PVP-(Mn–CdS) showed good developmental morphology. • 2% PVP-(Mn–CdS) enhanced the cationic degradation. • 2% PVP-(Mn–CdS)) showed 98% efficiency under visible light irradiation. [ABSTRACT FROM AUTHOR]

Environmentally toxic organic pollutants, namely methylene blue (MB), neutral red (NR), Rhodamine B (RhB), and methyl orange (MO) dyes contain highly toxic, carcinogenic, non-biodegradable, and colored pigments which cause harm for humans and aquatic organisms even at low concentrations. To detoxify these toxic organic pollutants from the wastewater, the bimetallic solid solution-typed In–Mo(O,S) 2 catalyst with various indium (In) contents were synthesized at low temperature through a simple precipitation method. The morphological, structural, chemical compositions, electrochemical and optical properties of the catalysts were thoroughly characterized. The photodegradation performance of the In–Mo(O,S) 2 catalysts over the cationic, anionic and neutral dyes were studied under visible light irradiation. It has been observed that the photocatalytic activity was enhanced as In was added to the Mo(O,S) 2 catalyst, and In–Mo(O,S) 2 -20 was found to be the best composition to completely degrade four organic dyes. The dye degradation had rate constant values of 9.5 × 10−2 min−1, 6.3 × 10−2 min−1, 4.4 × 10−2 min−1, and 15.7 × 10−1 min−1 for MB (20 ppm), NR (20 ppm), RhB (10 ppm), and MO (10 ppm) dyes, respectively. The active species for degradation of MB is different from those for RhB and MO. Single phase In–Mo(O,S) 2 -20 capable to degrade four kinds of dyes at a fast rate is a good photocatalyst. Image 1 • In–Mo(O,S) 2 -20 was synthesized at low temperature via simple precipitation method. • Single phase solid solution-type In–Mo(O,S) 2 -20 degraded four different organic dyes. • In–Mo(O,S) 2 -20 catalyst showed superior photocatalytic performance. • In–Mo(O,S) 2 -20 showed lower impedance and slower charge carriers recombination rate. • In–Mo(O,S) 2 -20 exhibit selective degradation for different dyes. [ABSTRACT FROM AUTHOR]