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In recent years, gadolinium (Gd)-based photocatalysts have been gaining attention for their exquisite properties and have been exploited as potential photocatalyst for environmental remediation. This review provides a comprehensive review on the photocatalytic activity of Gd-based nano-materials and their extensive application in environmental water treatment. Furthermore, this review describes the synthesis methods, optimization parameters, modification techniques, multifarious utilization, and anti-stokes upconversion properties of Gd nanomaterials. In addition, the drawbacks of Gd-based nanomaterials were discussed and have been addressed with modification techniques. Photocatalytic application of Gd-based nanoparticles (NPs), nanocomposite (NCs)/heterojunctions, dopants, and upconversion NPs has been discussed in detail. This review especially focuses on the influence of trivalent Gd dopant on the physical, magnetic, and photocatalytic properties of the most exploited host semiconductor photocatalysts. Furthermore, other photocatalytic applications of Gd NPs including hydrogen evolution, CO 2 reduction, and heavy metal removal have also been discussed. Toxicity studies on various forms of Gd have been evaluated to extend its application to industrial scale. Overall, this review sheds light on the recent developments in Gd-based nanomaterial in terms of its application in pollutant removal, advantages, and toxicity aspects. [Display omitted] • Discussed on recent progress in Gd-based nanomaterials for photocatalysis. • A comprehensive perspective to the rational design and fabrication of Gd based nanomaterials were summarized. • Influence of trivalent Gd dopant on host semiconductors has been elaborated. • Toxicity of Gd based materials has been discussed. • Knowledge gap, future perspective and challenges has been elaborated for effective application. [ABSTRACT FROM AUTHOR]

Water pollution is becoming an inevitable problem in today's world. Tons and tons of wastewater with hazardous pollutants are getting discharged into the clean water bodies every day. In this regard, photocatalytic environmental remediation using nanotechnology such as the use of organic, metal and non-metal based semiconductor photocatalysts for photodegradation of pollutants has gained enormous attention in the past few decades. This review is focused particularly on graphitic carbon nitride (g-C 3 N 4) which is a cheap, metal-free, polymeric photoactive compound and it is used as a potential photocatalyst in wastewater treatment. Though, pristine g-C 3 N 4 is a good photocatalyst, it has certain drawbacks such as poor visible light absorption capacity, quicker recombination of photoelectrons and holes, delayed mass and charge transfer, etc. As a result, the pristine g-C 3 N 4 catalyst is modified into novel 0D, 1D, 2D and 3D morphologies such as nano-quantum dots, nanorods, nanotubes, nanowires, nanosheets, nanoflakes, nanospheres, nanoshells, etc. It was also tailored into novel composites along with various compounds through doping, metal deposition, heterojunction formation, etc., to enhance the photocatalytic property of pure g-C 3 N 4. The modified catalysts showed promising photocatalytic performance such as degradation of majority of pollutants in the environment. It also showed excellent results in the removal or reduction of heavy metals. This review provides a detailed record of g-C 3 N 4 and its diverse photocatalytic applications in the past years and it provides knowledge for the development of such similar novel compounds in the future. [Display omitted] • The study highlights the g-C 3 N 4 based photocatalysts in wastewater treatment. • Synthesis of g-C 3 N 4 using different methods to obtain various morphologies. • Tailoring g-C 3 N 4 through doping, metal deposition, heterojunction formation. • Mechanism for wastewater treatment and H 2 production using photocatalytic process. • An outlook for exploration of novel g–C 3 N 4 –based nanomaterials in further studies. [ABSTRACT FROM AUTHOR]

Metal-organic frameworks (MOFs) are a distinct class of porous, crystalline materials with excellent photocatalytic activity. These inorganic-organic hybrids have gathered much attention because of their unique properties such as high surface area, vast structural diversity, pore surface characteristics, modifiable framework morphology and semiconductor nature. The synergistic effect provided by the customisable building blocks of MOFs has made them ideal candidates for designing versatile photocatalysts with superior performance. Hence, it becomes vital to present a glance of the recent breakthroughs in the development of various MOF-based photocatalysts to improve the pullbacks in this research area. This review gives an overall picture of the diverse range of MOF-based photocatalysts. The strategies that have been adopted to boost their photocatalytic activity such as post-synthetic modification (PSM), heterojunction designing, doping, introduction of co-catalysts, ligand or substituent functionalization, modulation of metal-oxidation state and bandgap engineering also been explained. Further, the review focuses on the early research developments, structural diversity, synthesis methods, cleaner production and the recent developments in MOF-based photocatalysts for various photocatalytic applications including hydrogen production, CO 2 conversion, photodegradation, photo electrochemical reaction (PEC), oxygen evolution reaction (OER) and fabrication of MOF-derived compounds. Finally, the futuristic challenges and scopes of MOFs as photocatalysts have been discussed. [Display omitted] • MOFs based photocatalysts for environmental remediation and clean energy production. • The strategies to boost their photocatalytic performance are explained. • Photocatalytic applications such as CO 2 conversion, H 2 production, etc are critically reviewed. • The futuristic challenges and research gaps in this area are discussed. [ABSTRACT FROM AUTHOR]

Our research demonstrates an improved visible light driven photocatalytic and anti-microbial activity of ZnS/Ag 2 WO 4 nanocomposite (NCs). ZnS/Ag 2 WO 4 NCs was synthesized via chemical co-precipitation method and the characterization was done by using UV–vis DRS, EDAX, XRD, XPS, FTIR, PL, HR-TEM, and N 2 adsorption-desorption. The crystalline nature and co-existence of ZnS and Ag 2 WO 4 NPs were verified by HRTEM, XRD and SAED analysis. The EDAX and XPS validate the presence of Ag, W, O, Zn and S. On comparison of ZnS/Ag 2 WO 4 with pure ZnS (3.52 eV), its band gap was shifted to 3.1 eV which enhanced the photocatalytic performance in visible region. The investigation of mechanism of methylene blue degradation by NCs was performed by scavenging test. The results suggests that hydroxyl radicals as the key species responsible for the photodegradation of MB. The photocatalytic degradation using ZnS/Ag 2 WO 4 (3 mg/L) reached 84% after 140 min. The pseudo-first-order kinetics suits well with MB degradation providing a good correlation coefficient values (R2 > 0.92) and it was fitted to the Langmuir–Hinshelwood model. XRD spectra of recycled ZnS/Ag 2 WO 4 remains same as prepared one indicates its resistance against photo-corrosion. The ZnS/Ag 2 WO 4 NCs showed excellent photocatalytic degradation efficiency compared to that of bare ZnS NPs and Ag 2 WO 4 NPs. The NCs exhibits a broad-spectrum antibacterial property against E. coli (gram -ve bacteria) and B. subtilis (gram +ve bacteria). The novel ZnS/Ag 2 WO 4 could be used as an efficient photocatalysts for the toxic pollutant degradation under visible light and as potent antibacterial agent. [ABSTRACT FROM AUTHOR]

Photocatalytic induction of electron/hole recombination, surface property and light response ability effectively enhance the photocatalytic activity of nanomaterial. In this work, the effective charge carrier separating Sn/Mn–ZnFe 2 O 4 –CdFe 2 O 4 –Ag 3 PO 4 Quantum dots (M/SZFO–CFO–AP QDs) was fabricated for photocatalytic degradation of doxycycline (doxy) antibiotic. The result showed enhanced photocatalytic activity of doxy and the degradation efficiency of doxy was about 98.8% in short span of time. The calculated WH plot and urbach energy of prepared photocatalyst exhibited evidence for the prevalence of point defects and its contribution to efficient charge separation and transferability. The total organic carbon (TOC) removal was found to be 98.9%, which depicts the complete mineralization of doxy. The synergetic charge transfer of n-p-n heterojunction enables the effective removal of doxy under visible light irradiation. Further, the genotoxicity study was determined by interacting the SZFO–CFO–AP QDs with Allium Cepa. The results depict that SZFO–CFO–AP QDs show lower toxicity level and there were no trace of defective mitotic phases and micro nuclei. Further, the progression and development of bean plant was determined after treating with prepared nanomaterials and the result showed the enhanced growth in SZFO–CFO–AP QDs treated bean plant compared to the counterparts. Therefore, the prepared SZFO–CFO–AP QDs was can be used as an environmental friendly photocatalyst for effective treatment of antibiotic present in the water bodies. [Display omitted] • Enhanced visible-light photocatalytic activity for the effective degradation of doxycycline. • Self-Fenton induced efficient photocatalytic degradation of doxycycline. • Enhanced photogeneration of.•OH, •O2 for the effective photodegradation of doxycycline. • An ecofriendly and non-genotoxic material for environmental remediation. [ABSTRACT FROM AUTHOR]

In this study, 3D C 2 S 3 (CS) and 2D Bi 2 S 3 (BS) modified NiCr 2 O 4 nanocomposite (NCO-BS-CS NCs) was prepared by sonochemical assisted co-precipitation method for the enhanced photocatalytic activity. Here, NCO-BS-CS NCs showed band gap energy of 2.23 eV and the PL intensity of NCO-BS-CS NCs was lower than NCO, BS, and CS NPs. Thus, the results indicate the fabricated NCO-BS-CS NCs enhance the charge segregation and lower in recombination rate. NCO-BS-CS NCs showed enhanced photodegradation of methyl orange (MO) (95%) and congo red (CR) (99.7%) respectively. The total organic compound (TOC) analysis shows the complete mineralization of about 91 and 98% for MO and CR respectively. Furthermore, the Fukui function was used for the prediction of reactive sites in the photodegradation pathway of MO and CR by NCs. ECOSAR program was done to determine the toxicity of the intermediate and the results conclude that the degraded product shows nontoxic to the environmental organism (fish, daphnia, and algae). Thus, the fabricated NCO-BS-CS NCs can be used for the remediation of toxic organic pollutants from the waste water by photocatalytic degradation. • NCO-BS-CS NCs was synthesized by sono-chemical coprecipitation method. • The NCO-BS-CS NCs showed outstanding visible-light photocatalytic activity. • NCO-BS-CS NCs demonstrates good photostability and reusability. • The hydroxyl and super oxide radical were responsible for the enhance photocatalytic activity. [ABSTRACT FROM AUTHOR]

Research on photocatalysis has boomed in the past two decades as it provides a sustainable solution to degrade organic pollutants. Among the several classes of photocatalyst, metal sulfides have drawn the attention due to its excellent solar spectral response and its notable electrical, optical, mechanical and magnetic properties where MoS 2 serves to be a promising one. Various characteristics of MoS 2 have rendered it as a preferable photocatalyst as well as a co-catalyst to degrade pharmaceutically active compounds (PhACs). Some of its prominent characteristics include its tunable band gap, enhanced absorption of visible light, layered structure, efficient photon-electron conversion, good photostability, non-toxic nature and quantum confinement effects. PhACs are one of the emerging pollutants of great concern which imparts severe effects on aquatic organisms and human health. This review focuses on the degradation of PhACs by the MoS 2 based photocatalysts that has been developed in the recent times. Further, the effect of various parameters that influences the photocatalytic activity of MoS 2 towards PhACs has also been discussed. [Display omitted] • The study highlights the importance of MoS 2 based photocatalysts in PhACs degradation. • Discussed about the properties of MoS 2 and its various synthesis routes. • Highlights the construction and role of MoS 2 based heterojunctions in photodegradation. • Evaluated the effect of various reaction parameters on photodegradation. • Explained the mechanism and photodegradation pathway. [ABSTRACT FROM AUTHOR]

The synthesis of CeO 2 /MnFe 2 O 4 NCs has been carried out by ultrasonication-assisted co-precipitation method. Transmission electron microscopic (TEM) analysis confirmed the embedment of MnFe 2 O 4 over CeO 2 with clear lattice fringes. Energy dispersive analysis (EDAX) and elemental mapping confirm the existence of elements including Ce, Mn, Fe, and O. The XRD patterns of the NCs indicated the effective construction of crystalline CeO 2 /MnFe 2 O 4 NCs with the co-existence of CeO 2 and MnFe 2 O 4 in desired molar ratio. The degradation rate constant of CeO 2 /MnFe 2 O 4 NCs-1:1 under visible light illumination was estimated to be 0.0108 min−1, which was 2.2 and 2.8 times greater than CeO 2 and MnFe 2 O 4 respectively. Here, the study provides a clear insight into the photocatalytic mechanism of the p-n type NCs, which exhibited efficient charge transfer and improved mobility. The scavenging assay and ESR analysis have explicated the major role of •OH radicals as the dominant reactive oxygen species on the photocatalytic degradation of MB dye. The photocatalytic efficiency of CeO 2 /MnFe 2 O 4 NCs-1:1 for MB dye degradation was found to be 86%. The results expressed almost similar degradation efficiency till the 6th cycle and the structural integrity of the NCs was found to be intact even after the photodegradation. Additionally, a predictive degradation pathway for MB was elucidated by Fukui function-based DFT analysis. The anti-microbial activity of the prepared samples was investigated against S. aureus and E. coli. Hence, the fabricated CeO 2 /MnFe 2 O 4 NCs-1:1 was concluded with the obtained results and it has been observed to be a potential candidate as an efficient photocatalyst for the elimination of toxic organic pollutants. [Display omitted] • CeO 2 /MnFe 2 O 4 NCs was synthesized by sono-chemical coprecipitation method. • The CeO 2 /MnFe 2 O 4 NCs showed outstanding visible-light photocatalytic activity. • The NCs demonstrates good photostability and reusability. • The hydroxyl radical was responsible for the enhance photocatalytic activity. [ABSTRACT FROM AUTHOR]

[Display omitted] • Z-scheme based nanocatalyst for the enhanced photo catalytic activity. • Enhanced photocatalytic activity by Z-scheme by various nanomaterial. • Effective photocatalytic application of the Z-scheme based nanocatalyst on pollutant removal of pharmaceutical pollutant. • Photocatalyst active sites of PhACs and challenges in photocatalysis. Photocatalysis is the process of exploitation of solar radiation for the creation of a pollution-free stable environment. Photocatalysis has applications in various fields including toxic pollutant degradation, heavy metal reduction, clean energy production (hydrogen generation by water splitting), and CO 2 reduction. Conventional photocatalyst has various shortcomings including poor visible light harvesting and faster charge recombination. The construction of Z-scheme heterojunctions can overcome these shortcomings and solve both the energy crisis and environmental degradation at once. This review is discussed based on the material aspects where interfacial charge transfer and internal electric field play a crucial role in the overall efficiency of a photocatalytic system. Firstly, semiconductors' redox potential and band gap are summarized as they are the key factor in photocatalysis. The charge transfer mechanism such as internal electric field and interfacial defects has been discussed to understand the material design of Z-scheme. Various semiconductor nanoparticles have been used for the construction of the Z-scheme, which has been compared and discussed extensively based on their effectiveness. This review intends to provide up-to-date works in Z-scheme, to guide future developments for better performance and maximum efficiency. [ABSTRACT FROM AUTHOR]

Novel photocatalyst CuO loaded ZnS nanoflower supported on carbon frame work PVA/Chitosan was synthesized by co-precipitation and ultrasonic assisted method. The co-existence of ZnS and CuO and its crystallinity in nanohybrid was verified by XRD, SAED and HR-TEM analysis. The availability of defects in ZnS was identified by EPR. FTIR and TGA verified the presence of PVA and Chitosan. Defects mediated ZnS–CuO/PVA/chitosan heterojunction promote synergistic charge separation with type II interface. Zn-vacancy facilitates two-photon excitation that improves visible-light harvesting. The photocatalytic activity of ZnS–CuO/PVA/Chitosan was 94.7% which is higher when compared to ZnS (40%) and CuO (60%). The photocatalytic mechanism was elucidated using scavenger test and both ·O 2 − and ·OH were found to play key role in tetracycline degradation. In addition, ZnS–CuO/PVA/Chitosan demonstrated efficient anti-microbial effect against the both gram strains on comparing with individual ZnS and CuO. Thus, the multifunctional ZnS–CuO/PVA/Chitosan is promising for the photocatalytic degradation of tetracycline and as an antimicrobial agent. • Zn-vacancy mediated charge separation and visible-light absorption in ZnS–CuO/PVA/chitosan. • Nanoflowers show remarkable tetracycline photo-degradation up to 94.7% without any cocatalyst. • The retention of strong redox potential e−/h+ pairs could afford to generate more ·O 2 − and ·OH radicals. • High photo-degradation by visible light-to-energy efficiency could be achieved for ZnS/CuO. • The nanoflowers showed improved bacterial growth inhibition. [ABSTRACT FROM AUTHOR]

The CdS/Ag 2 S nanocomposites (NCs) were synthesized by chemical co-precipitation technique. The optical properties and multifunctionality of the NCs were studied by evaluating photoluminescence, photocatalytic, antibacterial and anti-biofilm properties. The microscopic image indicated that the prepared CdS/Ag 2 S NCs were spherical shaped. The scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), electrochemical impedance spectroscopy (EIS), fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis indicates the successful formation of CdS/Ag 2 S NCs which were in nano-size. Brunauer–Emmett–Teller (BET) surface area analysis indicates the high surface area (57.23 m²/g) of NCs with narrow pore size. On comparison with pure Ag 2 S NPs (1.62 eV), CdS/Ag 2 S NCs bandgap had shift to 2.12 eV which facilitates visible light sensitization. The energy-dispersive X-ray spectroscopy (EDAX) analysis provides chemical composition details and possible electronic states observed via XPS core level scan of Ag3d, Cd3d and S2p. The activity of CdS/Ag 2 S NCs photocatalyst was estimated based on methylene blue (MB) dye degradation by irradiating under visible light. NCs showed excellent photocatalytic activity and at pH 8, the particles showed 95 ± 2.4% degradation of MB in 60 min. The ·O 2 - radical played key role in MB degradation. The CdS/Ag 2 S NCs exhibited a stable photocatalytic performance after six cycles. Total organic carbon (TOC) analysis of degraded product supported high mineralization of the pollutants. The NCs showed good antibacterial property against S. aureus and E. coli. The precoated CdS/Ag 2 S NCs showed greater inhibition in biofilm formation. CdS/Ag 2 S NCs also showed toxic effect on formed biofilm under dark and light condition. The research work testified that CdS/Ag 2 S NCs have potential applications in environmental treatment and antimicrobial applications. Possible photocatalytic mechanism of CdS/Ag2S [Display omitted] [ABSTRACT FROM AUTHOR]

• MnS/Ag 2 WO 4 NCs was prepared by chemical co-precipitation method. • The NCs showed efficient visible light photocatalytic activity than individual particles. • MnS/Ag 2 WO 4 showed potent anti-microbial activity against gram positive and gram negative microorganisms. • Experimental results demonstrated that OH• and •O2- are the major reactive species involved in dye degradation. • MnS/Ag 2 WO 4 NCs showed MB dye degradation potency of 92.3%. In this study, the novel MnS/Ag 2 WO 4 photocatalyst was synthesized via chemical co-precipitation method and investigated its physical and structural characteristics using HR-TEM, N 2 adsorption and desorption studies, FT-IR, EDAX, PL, UV–vis DRS, ESR, XPS and XRD. The estimation of photocatalytic activity of synthesized photocatalysts was done using methylene blue (organic dye) in aqueous solution. The photocatalyst efficiency was superior for MnS/Ag 2 WO 4 with degradation of 92.3% when compared with bare MnS (67.23%) and Ag 2 WO 4 (58.93%). The kinetic study reveals that higher reaction kinetic rate achieved by the MnS/Ag 2 WO 4 compared with MnS and Ag 2 WO 4. The scavenging test reveals that •OH and O2-• took the important part in the degradation process. The six cycles test reveals that the photocatalyst is highly reusable by showing similar degradation efficiency throughout the six cycles. MnS/Ag 2 WO 4 was also possessed potential broad spectrum anti-microbial activity against B. subtilis and E. coli. Hence, MnS/Ag 2 WO 4 heterostructure can be used as an excellent photocatalyst as well as an effective anti-microbial agent. MnS/Ag 2 WO 4 would be a cost-effective, highly efficient photocatalyst and a good antimicrobial agent. [ABSTRACT FROM AUTHOR]

• Novel FeV 2 O 4 nanospheres at surface of nanocube-like Bi 2 O 3 were synthesized. • UV-Vis-DRS, HRTEM, EDAX, SAED, XRD, BET, PL, VSM, XPS and FT-IR analysis were performed. • The photocatalytic rate of FeV 2 O 4 -Bi 2 O 3 was enhanced by 4.6–7 folds than pure NPs. • The mechanism of degradation was elucidated based scavenger response. • The FeV 2 O 4 -Bi 2 O 3 exhibited excellent antibacterial activity. Photocatalytic activity of nanocube structured Bi 2 O 3 was enhanced by loading FeV 2 O 4. XRD results reflected the crystalline nature of nanocomposites (NCs) consisting of FeV 2 O 4 and Bi 2 O 3. XPS confirmed the chemical states. FTIR peaks revealed that the M-O bonds had tetrahedral/octahedral structure. The FeV 2 O 4 -Bi 2 O 3 NCs have higher surface area in comparison with its constituent nanoparticles (NPs) which was confirmed using BET analysis. UV-Vis-DRS indicated the band gap shift of NCs to 2.59 eV which enhanced the visible-light sensitization. Optical and magnetic studies were carried out with photoluminescence and VSM analysis. The photocatalytic performance of the NCs was 4.6–7 times higher than that of its individual components. The ·OH is the key species involved in dye-degradation. High mineralization of the contaminants is supported by TOC analysis of degraded product. A stable photocatalytic performance of FeV 2 O 4 -Bi 2 O 3 was observed after six cycles. The growth inhibitory action of NCs against Escherichia coli and Bacillus subtilis confirmed its outstanding antimicrobial activity. The enhanced sunlight harvesting property and magnetic-removable nature have made FeV 2 O 4 -Bi 2 O 3 NCs as a noteworthy material to be applied in aqueous bodies to degrade threatening pollutants through photodegradation and as antimicrobial agent. [ABSTRACT FROM AUTHOR]

CdO/ZnFe 2 O 4 nanohybrid heterostructure was prepared by ultra-sonication assisted chemical precipitation technique in order to impose better separation of charge carriers, high photocatalytic and bactericidal activity. The formed CdO/ZnFe 2 O 4 nanocomposites (NCs) was characterized by UV-Vis-DRS, XPS, SEM, EIS, EDAX, VSM, SAED, HRTEM, FTIR, XRD, photoluminescence (PL) and BET surface area analyzer. CdO/ZnFe 2 O 4 poses narrow bandgap (2.04 eV) that enhanced the light harvesting in visible region. The high surface area of CdO/ZnFe 2 O 4 (53.6 m2/g) relative to CdO (44.9 m2/g) and ZnFe 2 O 4 (20.1 m2/g) provides more active sites that enhances the photocatalysis. The coupling of CdO and ZnFe 2 O 4 improved the life time of charge carriers as confirmed by PL analysis. The photocatalytic performance of NCs was evaluated based on methylene blue dye degradation. The photocatalytic degradation rate by NCs was enhanced 1.2 and 1.4 folds than CdO and ZnFe 2 O 4. VSM results showed super-paramagnetic nature of NCs with saturation of 42.4 emu/g which aids magnetic separation for its reusability. The reusability test of NCs showed almost same efficiency in all the 6 cycles. TOC analysis of degraded product supported high mineralization (71%) of MB. Scavengers' studies indicated the major role of h+ and OH· radical in dye degradation. In addition, CdO/ZnFe 2 O 4 NCs exhibited high antibacterial effect against S. aureus, B. subtils and E. coli. It is proposed that CdO/ZnFe 2 O 4 NCs could be applied as a promising photocatalyst for environmental remediation and as an antimicrobial agent [Display omitted] [ABSTRACT FROM AUTHOR]

In this paper, a novel MgS/Ag 2 MoO 4 nanocomposite (NCs) was synthesized for the evaluation of photocatalytic performance and anti-microbial activity. The particle was characterized using FT-IR, PL, HR-TEM, EDAX, XRD, XPS, SAED, UV–vis DRS, ESR, and EIS. The performance of the photocatalyst was improved by shift in band gap to 2.76 eV compared to its individual counter parts. The photocatalytic performance of MgS/Ag 2 MoO 4 NCs was much better than MgS and Ag 2 MoO 4 as individual particles. The reaction rate constant for degrading MB by MgS/Ag 2 MoO 4 was 0.011 min−1. The degradation efficiency of MgS/Ag 2 MoO 4 (90%) was about 1.5 and 2.2 times greater than bare Ag 2 MoO 4 (62%) and MgS (41%). The photocatalytic degradation efficiency remains same with 90% efficiency after performing the reusability test for six consecutive cycles under visible light irradiation and the particles maintained photo stability even after 6 cycles. The strong interactions between the interfacial surfaces are responsible for the increase in charge separation owing to the superior activity of MgS/Ag 2 MoO 4 NCs. The mechanism was established for this enhanced activity and the key reactive species, such as hydroxyl and superoxide radicals plays a major role in the photocatalytic process. The antimicrobial activity was evaluated against E. coli and B. subtilis and the activity of Ag 2 MoO 4 was good compared to NCs and MgS. The synthesized NCs are found to be good alternative as a visible light driven photocatalyst. [Display omitted] • MgS/Ag 2 MoO 4 NCs was synthesized by fast and facile sono-chemical method. • NCs formation improved the photocatalytic activity compared to its individual counter parts. • Achieved an effective interface transfer and separation of photoinduced electrons and holes. • The generation of both super oxide and hydroxyl radicals involved in the photocatalytic degradation. • Excellent antibacterial activity shown against E. coli and B. subtilis. [ABSTRACT FROM AUTHOR]

The unreported Bi 6 Cr 2 O 15 -Co 3 O 4 nano-photocatalyst was prepared via facile sono-chemical route for the fabrication of a binary heterojunction. HRTEM analysis represents the spherical and rod-like morphology of Bi 6 Cr 2 O 15 -Co 3 O 4. UV–vis DRS showed bandgap shift from 1.95 eV (Bi 6 Cr 2 O 15) and 2.67 eV (Co 3 O 4) to 2.25 eV for Bi 6 Cr 2 O 15 -Co 3 O 4 with visible-light sensitization. X-ray photoelectron spectroscopy (XPS) confirmed the chemical states (Co2p, Cr2p, Bi4f and O1s). The dye degradation efficiency of Bi 6 Cr 2 O 15 -Co 3 O 4 was highly boosted up to 3.8–8.8 times and the kinetic rate constant was 0.0062 min−1 compared with pristine counter parts (Bi 6 Cr 2 O 15 = 0.0016 min−1; Co 3 O 4 = 0.0007 min−1). The remarkably enhanced photocatalytic activity was ascribed to its higher specific surface area (27.118 m2/g) and the existence of a synergic effect between pristine counter parts that resulted in suitable bandgap and reduced recombination of e-/h+ pairs. The Bi 2 CrO 6 -Co 3 O 4 showed only negligible reduction in degradation performance after six recycles showing its excellent stability and resistance to photo-corrosion. The ·OH and h+ were the key species involved in dye degradation. The Bi 6 Cr 2 O 15 -Co 3 O 4 exhibited excellent antimicrobial activity against Escherichia coli and Bacillus subtilis. Therefore, Bi 6 Cr 2 O 15 decorated Co 3 O 4 nano-photocatalyst can be used as an effective candidate for environmental remediation through photocatalysis and for bactericidal applications. Pictorial representation of Bi 6 Cr 2 O 15 -Co 3 O 4 mechanism [Display omitted] [ABSTRACT FROM AUTHOR]

• The VS 4 /Ag 2 WO 4 were prepared by chemical co-precipitation method. • The photo-degradation activity of MB by VS 4 -Ag 2 WO 4 shows superior activity than the individual counter parts. • VS 4 -Ag 2 WO 4 possessed good stability after 6 cycles. • Excellent antibacterial activity shown by VS 4 -Ag 2 WO 4 against E. coli and B. subtilis. VS 4 /Ag 2 WO 4 nanocomposites (NCs) were synthesized successfully through facile co-precipitation and ultra-sonic assisted methods. VS 4 /Ag 2 WO 4 NCs was characterized by EDAX, UV–vis DRS, HR-TEM, XPS, XRD, PL, FT-IR, and BET surface area analyzer. The TEM image declares that VS 4 /Ag 2 WO 4 NCs are spherical shape with clear facets and narrow size distribution. The elemental composition (V, S, Ag, W and O) of as-prepared NCs was confirmed using EDX. FT-IR study established the loading and incorporation of Ag 2 WO 4 over VS 4. XRD results proved the polycrystalline nature of the prepared NCs and orthorhombic phase of Ag 2 WO 4. The degradation rate constant for MB by VS 4 /Ag 2 WO 4 was 0.0124 min−1 where it is 3.64 and 1.44 times higher than Ag 2 WO 4 (0.0038 min−1) and VS 4 (0.0086 min−1) respectively. The pseudo-first order kinetics was agreed well with degradation process. The photocatalytic mechanism was elucidated based on the scavengers and it was found that generation of •OH by VS 4 /Ag 2 WO 4 under visible light irradiation played the major role. The reusability and photostability were tested by performing consecutive 6 cycles where it retained the same degradation efficiency and crystal structure as same as first. The NCs possessed high antimicrobial activity against gram positive B. subtilis and gram negative E. coli. The information provided by these results confirms the great potential of NCs as a highly efficient photocatalyst for the removal of pollutants from water and as an excellent antimicrobial agent. [ABSTRACT FROM AUTHOR]

• Novel NiCr 2 O 4 decorated Bi 2 O 3 nanohybrid were synthesized. • UV-Vis-DRS, HRTEM, EDAX, SAED, XRD, EIS, BET, PL, XPS and FT-IR analysis were performed. • The photocatalytic activity was enhanced by 4–6 times than individual NPs. • The mechanism of degradation was elucidated based scavengers' response. • The NCs exhibited excellent antibacterial activity. This study investigates the enhancement of Bi 2 O 3 activity as photocatalyst by loading NiCr 2 O 4 as an effective catalyst. High-resolution transmission electron microscopy (HRTEM) analysis revealed the attachment of NiCr 2 O 4 nanospheres on surface of sheet-like Bi 2 O 3 nanoparticle (NPs). X-ray powder diffraction (XRD) revealed the successful fabrication of crystalline nanocomposites (NCs) with coexistence of NiCr 2 O 4 and Bi 2 O 3. X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray spectroscopy (EDAX) confirmed the elemental composition (Ni, Cr, Bi and O) with no trace of impurity. Peaks related to tetrahedral and octahedral oxygen-metal bonds were observed in fourier-transform infrared spectroscopy (FTIR). BET analyzer indicates presence of more reactive sites in NCs than individual NPs. UV–vis diffuse reflectance spectroscopy (DRS) showed shift in band gap of NiCr 2 O 4 (2.1 eV) and Bi 2 O 3 (2.8 eV) to 2.3 eV for NiCr 2 O 4 -Bi 2 O 3 NCs with visible light sensitization. The life time of charge carriers in NCs was greatly improved and it was revealed by photoluminescence (PL) study. The photocatalytic performance of NiCr 2 O 4 -Bi 2 O 3 NCs was higher with apparent kinetic constant (k app) of 0.012 min−1 which was 4–6 times boosted than its pure individual parts (Bi 2 O 3 = 0.003 min−1; NiCr 2 O 4 = 0.002 min−1). The study identified that ·OH play major role in dye degradation. The NiCr 2 O 4 -Bi 2 O 3 NCs exhibited a stable photocatalysis performance with good photostability after six cycles. In addition, NCs exhibited excellent antimicrobial activity against Escherichia coli and Bacillus subtilis. The potential usage of visible-light energy and operation simplicity prompted NiCr 2 O 4 -Bi 2 O 3 NCs as a promising magnetically removable candidate for photodegradation of toxic organic contaminants in the aqueous solutions and for antimicrobial applications. [ABSTRACT FROM AUTHOR]