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Rapid industrialization demands for effective nano-photocatalyst that works under visible-light irradiation. The effective p–n interfacial engineering in nanoparticles (NPs) offers better photocatalytic performance. High performing nano-heterojunction of intimately coupled n-copper ferrite (CuFe2O4) NPs on p-nickel oxide (NiO) NPs was prepared that mitigates the charge recombination. X-ray diffraction confirmed the coexistence of the rhombohedral NiO and tetragonal CuFe2O4 in the prepared NCs. The bandgap energy of NiO/CuFe2O4 NCs-30 is 2.18 eV which supports visible light photocatalysis. The rate constant for degrading the methylene blue (MB) dye by NiO/CuFe2O4 NCs-30 was about 0.010 min−1 which is 1.42 times and 2 times higher when compared to NiO and CuFe2O4 NPs. The reusability efficiency was 94.54%. It has been found that both OH⋅ and ⋅O2− radical formed and contributed in degrading MB dye. The importance of the prepared NCs can be understood from its effective performance and it can be concluded that it has high photocatalytic potential to degrade the aquatic pollutants. [ABSTRACT FROM AUTHOR]

In this study, a magnetic Fe3O4–CeO2 nano-heterojunction was fabricated on an organic matrix cetyl trimethylammonium bromide (CTAB) using a sonochemical method. The resulting nanocomposites (NCs) were used for the synergetic removal of tetracycline by adsorption and photocatalysis and their antimicrobial applications were also investigated. The average diameter and zeta potential of the NCs were 46 ± 2 nm and −33.24 ± 1.34 mV, respectively. The presence of the CTAB matrix was verified by FTIR analysis. The adsorption of tetracycline on the NCs was well fitted to the Langmuir model. The maximal adsorption was noted at pH 5. The photocatalytic degradation of tetracycline (25 mg L−1) by the NCs (10 mg L−1) reached 96.6% in 3 h under visible-light irradiation. The photocatalysis mechanism followed the S-scheme by retaining the photo-excited e−/h+ pairs with strong redox potential. The particles exhibited excellent antibiofilm and antibacterial activities. There was increased ROS generation and lipid peroxidation in the bacterial species upon exposure to the NCs. The bacterial antioxidant defense systems were disturbed upon exposure to the NCs. Therefore, the as-prepared Fe3O4–CeO2-CTAB NCs could be used as a promising candidate in wastewater treatment for disinfection applications and the adsorptive/photocatalytic removal of pharmaceuticals. [ABSTRACT FROM AUTHOR]

The present work is centred around the development of La 2 O 3 /(BiO) 2 CO 3 /Ag 3 PO 4 (LBA), a p-n-p nano-heterojunction to photodegrade doxycycline under visible light irradiation. Here, ultrasonication assisted co-precipitation method was employed to synthesize the photocatalyst. The photocatalyst was characterized using different analysis such as SEM, TEM, elemental mapping, XRD, XPS, FTIR, Raman, BET, DRS, PL and EIS which confirmed the successful fabrication of LBA and their excellent ability to refrain the e−/h+ recombination owing to the construction of the heterojunction. LBA was found to degrade DOX by 91.75 % with the high mineralization of 87.23%. The impact of the reaction parameters influencing the photodegradation process including the concentration of the NCs and DOX, pH and the influence of the commonly present anions were studied. The stability and reusability of the LBA was assessed through subjecting it to four cycles of photodegradation of DOX. In addition, the recovered LBA was characterized through XPS and XRD analysis to confirm the particles stability and reusability. The active participation of the photogenerated charges and the reactive oxygen species were identified through the scavenging assay and ESR analysis. Further, GC-MS/MS analysis was performed to put forward a plausible photodegradation pathway. The toxicity of the end products as well as the intermediates was predicted through ECOSAR software. [Display omitted] • LBA nano-hetrojunctionwas prepared via ultrasonication assisted co-precipitation method. • The photodegradation of doxycycline was found to be 91.75 %. • •OH and h+ were primarily involved in photocatalytic reactions. • The LBA nano-hetrojunction exhibited excellent photostability and reusability. • The degradation pathway was elucidated by GC-MS/MS analysis. [ABSTRACT FROM AUTHOR]

Physicochemical properties of titanium dioxide nanoparticles (TiO2 NPs) can be tuned by doping with metals or nonmetals. Copper (Cu) doping improved the photocatalytic behavior of TiO2 NPs that can be applied in various fields such as environmental remediation and nanomedicine. However, interaction of Cu-doped TiO2 NPs with human cells is scarce. This study was designed to explore the role of Cu doping in cytotoxic response of TiO2 NPs in human lung epithelial (A549) cells. Characterization data demonstrated the presence of both TiO2 and Cu in Cu-doped TiO2 NPs with high-quality lattice fringes without any distortion. The size of Cu-doped TiO2 NPs (24 nm) was lower than pure TiO2 NPs (30 nm). Biological results showed that both pure and Cu-doped TiO2 NPs induced cytotoxicity and oxidative stress in a dose-dependent manner. Low mitochondrial membrane potential and higher caspase-3 enzyme (apoptotic markers) activity were also observed in A549 cells exposed to pure and Cu-doped TiO2 NPs. We further observed that cytotoxicity caused by Cu-doped TiO2 NPs was higher than pure TiO2 NPs. Moreover, antioxidant N-acetyl cysteine effectively prevented the reactive oxygen species generation, glutathione depletion, and cell viability reduction caused by Cu-doped TiO2 NPs. This is the first report showing that Cu-doped TiO2 NPs induced cytotoxicity and oxidative stress in A549 cells. This study warranted further research to explore the role of Cu doping in toxicity mechanisms of TiO2 NPs. [ABSTRACT FROM AUTHOR]

• Facile synthesis of ZnO/MnFe 2 O 4 photocatalyst was achieved by the sonochemical method. • Efficient photocatalytic mineralization of Methylene blue dye was achieved. • ZnO/MnFe 2 O 4 showed excellent stability and reusability. • OH- radicals are the primary reactive species involved in the degradation of methylene blue. • Photocatalytic mechanism of ZnO/MnFe 2 O 4 and the degradation pathway were proposed. In recent times, the discharge of wastewater containing aromatic compounds has serious effects on human health and the environment. Thus the fabrication of an efficient and visible light-active nano photocatalyst offers an optimum and sustainable solution. In this study, ZnO/MnFe 2 O 4 nanocatalyst was fabricated by the ultrasonication mediated reflux method. The fabricated nanomaterials were characterized with SEM, TEM, XRD, XPS, UV-visible DRS, BET, EIS, PL, ESR analysis. The ensued nanocomposite (NCs) was employed for the photocatalytic removal of methylene blue (MB) dye. The photocatalytic efficiency of ZnO/MnFe 2 O 4 NCs for the removal of MB was 85% which was higher than the efficiency of both the individual semiconductors ZnO (63%) and MnFe 2 O 4 (69%). The rate constant for the photocatalytic removal of MB by ZnO/MnFe 2 O 4 NCs (0.07 min−1) was 12 times higher than the ZnO (0.006 min−1) and 1.75 times higher than MnFe 2 O 4 (0.04 min−1). The boosted photocatalytic performance of ZnO/MnFe 2 O 4 was attributed to the higher surface area (204.559 m2/g) with more active sites compared to ZnO (188.212 m2/g) and MnFe 2 O 4 (106.893 m2/g). The as-fabricated ZnO/MnFe 2 O 4 NCs possess excellent stability as affirmed by recycle test and the analysis of reused XRD. The major part of the degradation of MB was performed by •OH− radicals which was confirmed by scavenging test. The overall results suggest that the fabricated ZnO/MnFe 2 O 4 is an active material for photocatalytic applications. [Display omitted] [ABSTRACT FROM AUTHOR]

Hetero-junction Y2O3/TiO2 nano-composite (NC) photocatalysts were synthesized using a conventional hydrothermal method (Y2O3/TiO2 NC(HM)) and an ionic liquid assisted hydrothermal method (Y2O3/TiO2 NC(ILAHM)). The composite nature and physico-chemical properties of the photocatalysts prepared through both routes as a function of thermal treatment were investigated via thorough characterization. A comparison of the photocatalytic hydrogen production via water splitting is provided. It was found that the concentration of Y2O3 in the TiO2 matrix and the post thermal treatment have obvious effects on the hydrogen production activity, and they were fine-tuned for enhancement of the hydrogen production. The required synergy between Y2O3 and TiO2 was found to occur at an optimum concentration of 25 wt% Y2O3 in the TiO2 matrix, with the sample prepared at 400 °C for 1 h. The optimized NC i.e. 25 wt% Y2O3/TiO2 NC(ILAHM) produced a promising hydrogen evolution of 1380 μmol g−1 that was almost 2-fold the production from 25 wt% Y2O3/TiO2 NC(HM). The enhancement was attributed to the porous surface morphology, higher surface area and quantum yield of the NC prepared using the ionic liquid assisted hydrothermal method. [ABSTRACT FROM AUTHOR]

Highly effective ZnO–CdO nanohybrid particles were synthesized via a hydrothermal co-precipitation method and characterized by X-ray diffraction (XRD), field emission-scanning electron microscopy (FESEM), particle size analyzer, zeta sizer and Brunauer–Emmett–Teller (BET) surface area analysis. ZnO–CdO-3:1 nanohybrid photocatalyst exhibited significantly enhanced photostability and photocatalytic activity for the degradation of Methylene Blue. The formation of hydroxyl radicals was measured by photoluminescence (PL) spectroscopy. Photocatalytic efficiency of ZnO was high at ZnO–CdO ratio of 3:1. Furthermore, this work provides an insight into the development of a new photocatalyst for the degradation of organic contaminants. [ABSTRACT FROM AUTHOR]

• CaFe 2 O 4 -ZnO nanocomposite was constructed by chemical co-precipitation method. • Photocatalysis rate of NCs was 13.5 and 9 folds higher than pristine CaFe 2 O 4 and ZnO. • Photoluminescence study revealed the reduced recombination rate of e−/h+ pairs. • The OH· radical is the dominant species in dye degradation. • The nanohybrid exhibited excellent antibacterial activity. Environmental pollution demands the fabrication of suitable nano-photocatalyst that works under white-light irradiation. The effective interfacial engineering is required for better separation of charges. Here, the novel magnetic CaFe 2 O 4 -ZnO nanophotocatalyst was synthesized by adopting a sonochemical method. The CaFe 2 O 4 -ZnO was analyzed using HRTEM, XRD, FTIR, BET, UV-visible DRS, BET, EIS, and photoluminescence analysis. The photocatalytic performance of CaFe 2 O 4 -ZnO is evaluated by decolourization of Rhodamine B (RhB). Further, the particles' multifunctionality was evaluated by testing its antibacterial activity against Bacillus subtilis and Escherichia coli under dark and light. Here, 97.5% of RhB (25 mg/L) was degraded by CaFe 2 O 4 -ZnO (60 mg/L) under visible light. The kinetic rate of photocatalysis by CaFe 2 O 4 -ZnO was 0.027 min−1 which was 13.5 and 9 folds higher relative to pristine CaFe 2 O 4 and ZnO. At pH 9, the RhB displayed higher photodegradation. Trapping experiments indicate · OH radical severe a key role in RhB degradation. The formation of p-n interface boosted better charge separation and improved ROS generation. At 50 mg/L CaFe 2 O 4 -ZnO, the antibacterial performance under light was 98% against B. subtilis and 99.9% against E. coli. The present study reports CaFe 2 O 4 -ZnO nanophotocatalyst for the effective environmental remediation through photocatalysis and as an antibacterial agent. Photocatalytic mechanism of CaFe 2 O 4 -ZnO nanocomposite. [Display omitted] [ABSTRACT FROM AUTHOR]

• 3-(Trimethoxysilyl) propyl methacrylate stabilized Ag-Fe nanocomposite was synthesized by chemical reduction method. • The Ag-Fe nano composite-glycine conjugate was able to detect Hg2+ in aqueous sample. • Ag-Fe nanocomposite showed high selectivity and sensitivity towards the detection of Hg2+. • The limit of detection of Hg2+ by Ag-Fe nano composite was 1.84 nM. • The Ag-Fe nanocomposite exhibit excellent photocatalytic and antimicrobial activity. In this study, a selective and sensitive colorimetric probe for the detection of mercury at nanomolar level was reported and the effective detection by the probe was performed with environmental samples. The colorimetric sensing platform was prepared based on Ag-Fe bimetallic- 3-(Trimethoxysilyl) propyl methacrylate framework. The UV–vis spectroscopy, X-Ray diffraction, high resolution transmission electron microscope, energy dispersive X-ray spectroscopy (EDS), thermal gravimetric analyzer, zeta sizer and particle size analyzer were used for the characterization of Ag-Fe nanocomposite. The detection of mercury by Ag-Fe-glycine nanoconjugate was indicated by the colour change from yellowish brown to colourless. The environmental sample was collected from Noyyal river and the estimated amount by the probe was almost similar to the result of atomic absorption spectroscopy analysis. The detailed study on the effect of pH, temperature and saline concentration on the detection was performed. In addition, metal interference study was performed to understand the influence of other metal ions on detection and quantification of Hg2+ by Ag-Fe-glycine nanoconjugate and the study reveals the practical application of the prepared probe. The limit of detection of Hg2+ by Ag-Fe nanocomposite was determined to be 1.8 nM. The prepared probe is found to be an effective system to detect mercury at very low nanomolar level from aqueous samples. In addition, the nanocomposite exhibited multifunctional properties including efficient photocatalytic and antimicrobial applications, indicates its wide applications in various sectors. [ABSTRACT FROM AUTHOR]

The predatory bacterium, Bdellovibrio bacteriovorus , was applied as a biological pre-treatment to solar disinfection and solar photocatalytic disinfection for rainwater treatment. The photocatalyst used was immobilised titanium-dioxide reduced graphene oxide. The pre-treatment followed by solar photocatalysis for 120 min under natural sunlight reduced the viable counts of Klebsiella pneumoniae from 2.00 × 109 colony forming units (CFU)/mL to below the detection limit (BDL) (<1 CFU/100 μL). Correspondingly, ethidium monoazide bromide quantitative PCR analysis indicated a high total log reduction in K. pneumoniae gene copies (GC)/mL (5.85 logs after solar photocatalysis for 240 min). In contrast, solar disinfection and solar photocatalysis without the biological pre-treatment were more effective for Enterococcus faecium disinfection as the viable counts of E. faecium were reduced by 8.00 logs (from 1.00 × 108 CFU/mL to BDL) and the gene copies were reduced by ∼3.39 logs (from 2.09 × 106 GC/mL to ∼9.00 × 102 GC/mL) after 240 min of treatment. Predatory bacteria can be applied as a pre-treatment to solar disinfection and solar photocatalytic treatment to enhance the removal efficiency of Gram-negative bacteria, which is crucial for the development of a targeted water treatment approach. Image 1 • Pre-treatment with predatory bacteria effectively disinfected Gram-negative bacteria. • Solar disinfection/photocatalysis effectively disinfected Gram-positive bacteria. • Predatory bacteria could serve as an additional strategy to optimise rainwater treatment. [ABSTRACT FROM AUTHOR]

The study describes a simple and novel method for the synthesis of silver sulfide nanoparticles (Ag 2 S NPs). The synthesized NPs were characterized by SEM (scanning electron microscope), XRD (X-ray diffraction), particle size analyzer, zeta sizer and EDX (Energy dispersive X-ray). The Ag 2 S NPs were spherical in shape with an effective diameter size of 30 nm. The synthesized particles possess photocatalytic activity under visible light and exhibited excellent antimicrobial effect. The photocatalytic property of Ag 2 S NPs was also evaluated by the degradation of methylene blue dye under visible light. NPs degraded 87% of methylene blue with in 1 h at pH 8. The NPs of 0.1 μg/mL showed a growth inhibition of more than 75% against S. aureus (ATCC 25923), E. coli (ATCC 13534), and E. coli (ATCC 25922). [ABSTRACT FROM AUTHOR]

Zinc oxide nanoparticles (ZnO NPs) are widely used in consumer products including sunscreens, textiles and paints. The indiscriminate use of such materials may leads to its release into the environment. The present study evaluated the photocatalytic effect of ZnO NPs in presence of humic acid (HA), which is an important factor present largely in the environment. ZnO NPs were characterized by using UV-visible spectrophotometer, scanning electron microscopy, particle size analyzer and X-ray diffraction analysis. The mean diameter of the particles was found to be 55 ± 2.1 nm. The XRD patterns exhibited hexagonal structure for ZnO NPs. The photocatalytic activity of ZnO NPs was evaluated based on the change in UV-visible absorption spectra of the methylene blue solution as a function of reaction time under visible light source. The rate of photocatalytic degradation of methylene blue was decreased with increase in HA concentration. [ABSTRACT FROM AUTHOR]

Highlights: [•] Cadmium sulfide nanoparticles were synthesized by chemical co-precipitation method. [•] Nanoparticles were spherical in shape and the size of NPs is 5–65nm in diameter. [•] The particles were highly stable. [•] Cadmium sulfide nanoparticles possessed efficient photocatalytic property. [•] The particles exhibited excellent antimicrobial activity. [Copyright &y& Elsevier]

Today, a major concern associated with the environment is the water pollution occurred due to the introduction of variety of persistent organic pollutants and residual dyes from different sources (e.g., dye and dye intermediates industries, paper and pulp industries, textile industries, tannery and craft bleaching industries, pharmaceutical industries, etc.) into our natural water resources. Recently, advanced oxidation processes (AOPs) by photocatalyst have garnered great attention as a new frontier promising eco-friendly and sustainable wastewater treatment technology. Utilization of the photocatalytic technology efficiently is significant for cleaner environment. Bismuth based photocatalyst have aroused widespread attention as a visible light responsive photocatalyst for waste water treatment due to their non-toxicity, low cost, modifiable morphology, and outstanding optical and chemical properties. In this review, we have dealt with the research progress on bismuth-based photocatalysts for waste water treatment. However, it seems to give limitation over pristine photocatalysts such as slow migration of charge carriers, charge carrier recombination, low visible light absorption, etc., Various bismuth based photocatalyst and its modifications via doping, heterojunction, Z-scheme etc., are discussed in detail. Further, the strategies adopted to improve the photocatalytic activity of bismuth based photocatalyst to improve the waste water treatment (mostly drugs and dyes) are critically reviewed. Also, we have discussed the bacterial inactivation by bismuth based photocatalyst. Finally, the challenges and future aspects against bismuth based photocatalyst are explored for further research. [Display omitted] • Bismuth based photocatalyst are used for the efficient treatment of waste water. • Addressed issues relating to water pollution and effluent treatment using photocatalysis process. • Modified strategies and defect regulations for effective degradation of toxic pollutants. • Application of bismuth based photocatalyst on treating pollutants, antimicrobial activity and Cr (VI) reduction. • A limitation and future aspect of bismuth based photocatalyst is discussed. [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]

The global health landscape is increasingly threatened by antimicrobial resistance, prompting a search for pioneering interventions. The current study focused on the construction of non-metal doped SnO 2 nanorod decorated with Fe 3 O 4 nanospheres through hydrothermal techniques. The prepared N/S-SnO 2 @Fe 3 O 4 nano-heterojunction was evaluated by performing photocatalytic degradation of tetracycline (TET) under visible light illumination. Out of various combinations tested, S-SnO 2 @Fe 3 O 4 nano-heterojunction was found to degrade TET by 98.3% with a TOC removal of 97%. S-SnO 2 @Fe 3 O 4 nano-heterojunction and its constituents were characterized by using TEM, SEM, XRD, DRS, PL, Raman, XPS, EIS, BET and FTIR. The influence of factors such as pH, ions, S-SnO 2 @Fe 3 O 4 dosage and TET concentration on photodegradation were investigated. Furthermore, the stability and reusability of S-SnO 2 @Fe 3 O 4 nano-heterojunction were assessed through six consecutive cycles of TET photodegradation. XPS and XRD analyses characterized the recovered nano-heterojunction, while scavenging assays and ESR analysis identified as •OH is the main reactive oxygen species involved in TET photodegradation. Additionally, GC-MS/MS analysis proposed a photodegradation pathway, and ECOSAR was used to predict the toxicity of intermediates. • N/S-SnO 2 @Fe 3 O 4 nano-hetrojunction was prepared by hydrothermal method. • The photodegradation of tetracycline was 98.3% with high mineralization of 97%. • •OH and h+ are involved in photocatalytic reactions. • The S-SnO 2 @Fe 3 O 4 nano-hetrojunction exhibited excellent photostability and reusability. • The degradation pathway was elucidated by GC-MS/MS analysis. [ABSTRACT FROM AUTHOR]

[Display omitted] • Photocatalytic nano-materials reviewed for the degradation of ibuprofen. • Remediation performance and mechanism are qualitatively and quantitatively described. • Interfacial regulation strategies of catalysts to improve degradation of ibuprofen. • Toxic effects of ibuprofen, end products of degradation on aquatic organisms, human beings, etc., were discussed. The usage of personal care products, pharmaceutically active compounds, dyes, and pesticides causes a great impact on aquatic organisms as well as human beings. Elimination of such persistent and eco-toxic pharmaceutically active compounds present in the sewage is a vital thrust area in environmental management. The designing and fabrication of efficient photocatalyst for degrading such compounds is one of the challenging and interesting aspects of photocatalysis. In this review, interfacial regulation strategies of photocatalysts, degradation pathways, and eco-toxicological effects of ibuprofen along with its intermediates have been discussed. Interfacial regulation strategies of catalysts can improve their performances in the degradation of ibuprofen by photocatalysis. The construction of nano-heterojunction and selection of co-catalyst is one of the most important parts for improving the catalyst performance. The photocatalytic efficiency of nano-heterojunctions is higher owing to its low rate of electron-hole (e−/h+) recombination, cost efficiency and improved light utilization. The role of co-catalyst in charge separation and electric conductivity has been discussed. The degradation efficiency of different photocatalysts has been collectively discussed. The toxic effects of ibuprofen on aquatic organisms, human beings, etc., have been discussed briefly. The photocatalytic degradation pathway of ibuprofen based on the active radical and the intermediate compounds along with their toxicity have been compared to other pharmaceuticals in this review. The future scopes in photocatalysis technology and its practical applications have been discussed. [ABSTRACT FROM AUTHOR]

A morphological oriented highly active Cu 2 O–Ag–CaWO 4 (CAC) nano-heterojunction was fabricated for the visible light driven degradation of rifampicin (RFP). Octahedron shaped Cu 2 O being a base material, where the Tagetes shaped CaWO 4 and Ag were embedded on it. The shape-controlled morphology of Cu 2 O and CaWO 4 as well as Ag decoration influence high degree of adsorption of RFP and interfacial charge transfer between the nano-heterojunction. Further, the larger specific surface area (129.531 m2/g) and narrow band gap energy (2.57 eV) of CAC nano-heterojunction than the controls support the statement. Positively, CAC nano-heterojunction following Z-scheme-type charge transport mechanism attained 96% of RFP degradation within 100 min. O 2 •- and •OH are the primarily involved reactive oxidation species (ROS) during the photocatalytic reactions, determined by scavenger study and ESR analysis. The stability and reusability of the CAC nano-heterojunction was assessed through performing cyclic experiment of RFP degradation and it holds 96.8% of degradation even after 6th cycle. The stability of CAC nano-heterojunction after photodegradation was further confirmed based on crystalline pattern (XRD analysis) and compositional states (XPS analysis). Intermediates formed during RFP degradation and its toxicity was discovered by using GC-MS/MS and ECOSAR analysis respectively. The end-product toxicity against bacterial system and genotoxicity of CAC nano-heterojunction against Allium cepa were evaluated and the results were seemed to have no negative causes for the aquatic lives. • CAC nano-heterojunction with Z-scheme-type charge transport mechanism was fabricated for RFP degradation. • CAC nano-heterojunction attained 96% of RFP degradation within 100 min. • O 2.•- and •OH are the primarily involved ROS during the photocatalytic reactions. • Degradation pathway was proposed using GC-MS/MS analysis. • Toxicity studies against bacterial system and Allium cepa was employed. [ABSTRACT FROM AUTHOR]

In this work, a simple g-C 3 N 4 quantum dots enriched MoO 3 nanohybrid was formulated for the synergistic photocatalytic degradation of an industrially active organic pollutant, p-chlorophenol (PCP) and a widely prescribed antibiotic, rifampicin (RIF). The nanohybrid was synthesised via a facile ultrasonic assisted hydrothermal method and characterized using various characterization analysis. The efficient Z-scheme charge transfer of the nanohybrid resulted in the elimination of 98% PCP and 89% RIF under visible light with a rate constant of 0.012 and 0.006 min−1 respectively. The photocatalysis was attributed to the formation of both hydroxyl (OH•) and superoxide (O 2 •-) radicals in the resulting nanohybrid. The intermediates formed in the course of reaction were estimated through gas chromatography-mass spectroscopy/mass spectroscopy (GC-MS/MS) analysis and a suitable degradation pathway was constructed. The structural stability and reusability of the nanohybrid was affirmed through X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis to outweigh the industrial potential of the catalyst, with 85% PCP and 80% RIF removal efficiency after six cycles of degradation. In addition, the mineralization of the pollutants was confirmed by total organic carbon analysis. Further, the toxicity of the drug and the formed intermediates was determined using ecological structure activity relationships (ECOSAR) software. On the whole, this work provides an excellent insight for the development of environment-friendly materials in a large scale for the degradation of water-based pollutants. [Display omitted] • A novel g-C 3 N 4 QDs incorporated MoO 3 catalyst was successfully fabricated. • Superior degradation of about 98% p-chlorophenol and 89% rifampicin was achieved in 330 min. • Led to the mitigation of charge carriers and improved visible light activity. • Porous nature of g-C 3 N 4 QDs facilitated more surface-active sites for efficient adsorption. • Exhibition of Z-scheme mechanism with both.•OH and •O 2 − radicals responsible for photocatalysis. [ABSTRACT FROM AUTHOR]

Novel ZnS–Cu 7 S 4 nanohybrid supported on chitosan matrix, as an ideal photocatalyst, was fabricated by the sonochemical method wherein high-resolution transmission electron microscopy (HRTEM) and X-ray powder diffraction (XRD) analysis confirmed the co-existence of both ZnS and Cu 7 S 4 ; presence of vacancy sites in ZnS was verified by electron paramagnetic resonance (EPR) analysis and their introduction could promote two-photon excitation facilitated visible light response and charge transport/separation. The type II interface is formed in the ZnS–Cu 7 S 4 /Chitosan heterojunction owing to interstitial states that promote charge separation. The ZnS–Cu 7 S 4 /Chitosan was used for the photodegradation of a pharmaceutical pollutant, p -chlorophenol (PCP); over 98.8% of PCP photodegradation was achieved under visible-light irradiation where the ensued ·O 2 − and ·OH serve a key role in the photodegradation of PCP. In vitro cytotoxicity studies substantiated that the ZnS–Cu 7 S 4 /Chitosan is nontoxic to the ecosystem and human beings and endowed with promising photodegradation properties and accessibility via an environmentally friendly design, bodes well for its potential remediation applications. [Display omitted] • ZnS–Cu 7 S 4 /chitosan type II heterojunction showed 98.8% photodegradaion of p-chlorophenol. • Defect engineering to promote synergistic charge separation and visible-light absorption. • The Cu 7 S 4 and ZnS NPs appears to be in spine and nanocube shaped. • Formation of both ·O 2 − and ·OH radicals to boost pollutants degradation. • The In vitro cytotoxicity assay suggests that ZnS–Cu 7 S 4 /chitosan is non-toxic. [ABSTRACT FROM AUTHOR]

Photocatalysis is a reliable technology to treat polluted wastewater. Herein, we report S-scheme photocatalyst namely ZnS/CdS nanocomposites (NCs) with S-vacancies and interstitial defect states, immobilised on the polymer matrix of cellulose and chitosan. It showed significant performance in photocatalytic degradation of Rhodamine B (RhB) dye. Defect sites present in ZnS facilitates charge separation and two-photon excitation concomitantly with a bandgap shift in ZnS/CdS NCs to 2.65 eV and promotes visible light harvesting. XRD analysis demonstrated the highly crystalline nature of the NCs. TEM and SEM were used to observe the crystal phases, particle morphology and defect sites. XPS and EDAX ensured the composition and purity of the synthesized NCs. FTIR displayed the peaks representing the bonds present in metal sulphides and chitosan/cellulose matrix. The photodegradation of RhB by ZnS/CdS NCs reached a maximum of 99.18% in 120 min which displayed 6.8 and 10.25 times higher rate than pure ZnS and CdS respectively. Further, ZnS/CdS NCs was able to achieve the TOC reduction of 86% after the photodegradation of RhB. Defect engineering played a vital role in enhancing the photocatalytic activity of NCs. PL spectra revealed the prolonged life time of photogenerated charge carriers and EIS analysis was used to investigate the charge mobility of the fabricated materials. Superoxide radical was found to be the major radical involved in photodegradation of RhB by NCs. The degradation pathway of RhB was elucidated based on GC-MS/MS analysis. The recyclability of NCs was tested for six consecutive cycles and remarkable stability was observed. The results of in vitro cytotoxicity assay, and cellular reactive oxygen species generation suggest that ZnS/CdS NCs are safety photocatalysts to environment and human being. [Display omitted] S-scheme heterojunction of ZnS/CdS NCs on cellulose/chitosan matrix was fabricated. S-vacancies and interstitial defect states brought in the play of two-photon excitation. This aided bandgap tuning, visible light sensitization and reduced charge recombination. Remarkable Rhodamine B photodegradation of 99.18 % was achieved. In vitro cytotoxicity assay suggested the non-toxic nature of the NCs. [ABSTRACT FROM AUTHOR]

Biosynthesis of nanomaterials using plant extract makes them attractive in the field of photocatalysis as they are environmental friendly. The current study focused on the biosynthesis of ZnO/NiCo 2 S 4 QDs (NCs) using Punica granatum fruit peel extract as the reducing agent. The nanomaterials were characterized with XRD, FTIR, Raman, SEM, TEM, UV–vis DRS, BET, PL, EIS, and ESR analysis and were used for photocatalytic degradation of doxycycline (DOX) and ciprofloxacin (CIP). The bandgap of ZnO is 3.2 eV, and the decoration of NiCo 2 S 4 QDs aids in narrowing the bandgap (2.8 eV), making the NCs visible light active. The fabricated NCs achieved 99 and 89% degradation of DOX and CIP respectively. The photocatalytic efficiency of ZnO/NiCo 2 S 4 QDs was much higher compared to individual ZnO and NiCo 2 S 4 QDs. The half-life period of DOX and CIP were evaluated to be 58 and 152 min respectively. The percentage of TOC removal in the photodegraded product of DOX and CIP was estimated to be 99 and 89% respectively, indicating the mineralization of the compounds. The enhanced photocatalytic efficiency of the NCs was attributed to the narrowed visible light active bandgap, synergistic charge transfer across the interface, and lower charge recombination. The intermediates formed during the photocatalytic degradation of DOX and CIP were analyzed using GC-MS/MS analysis, and the photodegradation pathway was elucidated. Also, the toxicity of the intermediates was computationally analyzed using ECOSAR software. The fabricated ZnO/NiCo 2 S 4 QDs have excellent stability and reusability, confirmed by XRD and XPS analysis. The reusable efficiency of the NCs for the photocatalytic degradation of DOX and CIP were 98.93, and 99.4% respectively. Thus, the biologically fabricated NCs are shown to be an excellent photocatalyst and have wide applications in environmental remediation. [Display omitted] • ZnO/NiCo 2 S 4 QDs photocatalyst was synthesized using P. granatum fruit peel extract. • ZnO/NiCo 2 S 4 QDs showed excellent photocatalytic removal of doxycycline and ciprofloxacin. • The NCs showed excellent stability and reusability. • Photocatalytic mechanism of ZnO/NiCo 2 S 4 QDs and the degradation pathway was proposed. • ZnO/NiCo 2 S 4 QDs can be used as a promising and potential industrial wastewater treatment tool. [ABSTRACT FROM AUTHOR]

Zinc oxide nanoparticles (ZnO NPs) are extensively used in a wide variety of commercial products including sunscreens, textiles and paints It is a known fact that ZnO NPs are not stable when dispersed in water, therefore manufacturers use several surface modifying agents to increase the stability of ZnO NPs. In the present study, ZnO NPs were synthesized via chemical co-precipitation with and without the use of surface modifying agents including ethylene glycol (EG), gelatin, polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP). Preliminary characterization was done by UV–Visible spectroscopy. Electron microscopic analysis showed that the particles were hexagonal in shape. The hydrodynamic size distribution was analyzed by using dynamic light scattering method and crystalline nature was determined by X-ray diffraction method. The study evaluated the photocatalytic, antibacterial and antibiofilm activities of the particles with and without the addition of surface modifying agents. The capping of the particle was confirmed by FT-IR spectroscopy. The photocatalytic activity was checked against methylene blue. Capping of the particles reduced the photocatalytic activity of the particles. The antibacterial and antibiofilm activities were checked against Staphylococcus aureus (MTCC 3160) and Pseudomonas aeruginosa (MTCC 1688). Antibacterial activity was analyzed by simple plate count method both under dark as well as light condition. Antibiofilm activity was checked in both pre- and post-biofilm formation period under both dark as well as light condition. The activity was evaluated via crystal violet staining method. All the particles showed good antibacterial and antibiofilm activities. [ABSTRACT FROM AUTHOR]

Sustainable wastewater treatment is crucial to remediate the water pollutants through the development of highly efficient, low-cost and separation free photocatalyst. The aim of this study is to construct a novel CoNiO 2 –BiFeO 3 –NiS ternary nanocomposite (NCs) for the efficient degradation of organic pollutants by utilising visible light. The NCs was characterized by various physiochemical techniques, including HR-TEM, SEM, XPS, FT-IR, ESR, EIS, PL, UV–visible DRS, and N 2 adsorption and desorption analysis. The photocatalyst exhibits extraordinary degradation efficiency towards MO (99.8%) and RhB (97.8%). The intermediates were determined using GC-MS analysis and the degradation pathway was elucidated. The complete mineralization was further confirmed by TOC analysis. The CoNiO 2 –BiFeO 3 –NiS ternary NCs have shown excellent photostability, structural stability and reusability even after six cycles and it is confirmed by XRD and XPS analysis. The kinetic study reveals that the photodegradation of the dyes follows first order reaction. The influence of different pH, dye concentrations and NCs dosages were investigated. The intermediate toxicity was predicted by computational stimulation using ECOSAR software. The NCs shows promising potential for ecological safety which demonstrates its practical application in the treatment of waste water pollutants in large scale. • A novel CoNiO 2 –BiFeO 3 –NiS ternary nanocomposite (NCs) shows excellent photocatalytic performance. • The synthesized CoNiO 2 –BiFeO 3 –NiS ternary nanocomposite were successfully characterized. • The NCs showed an excellent Z-scheme photocatalytic degradation. • The NCs demonstrated MO (100%) and RhB (96.7%) dye degradation. • The NCs displayed tremendous stability for six photocatalytic cycles. [ABSTRACT FROM AUTHOR]

Zinc oxide nanoparticles (ZnO NPs) are largely used in consumer products and industrial applications. The increased use of such materials may lead to its release into the environment. The study used chemically synthesized ZnO NPs and characterized by using UV–visible spectrophotometer, scanning electron microscopy, particle size analyzer and X-ray diffraction (XRD) analysis. The mean diameter of the particles was found to be 55 ± 1.2 nm. The XRD patterns exhibited hexagonal structure for ZnO NPs. The photocatalytic property of ZnO NPs was evaluated based on the UV–vis spectra changes of the methylene blue solution as a function of reaction time in the presence of ZnO NPs under visible light. The study suggests that ZnO NPs can be used as an efficient photocatalyst and the environmental factor such as exopolysaccharides could mask the photocatalytic activity of NPs. [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]

• Mesoporous γ-Al 2 O 3 coupled 2D hexagonal CdO nanoplates as photocatalyst • Prepared using ultrasonic assisted method with good crystallinity • Tailored bandgap energy of CdO/Al 2 O 3 was 2.95 eV with visible light sensitization • Photodegradation of synthetic cationic dye followed first order kinetics • The particles exhibited excellent antibacterial activity The mesoporous network of γ-Al 2 O 3 ceramic support was coupled with the two dimensional (2D) hexagonal CdO nanoplates by ultrasonic assisted method. The fabricated photocatalyst was analyzed for its structural, morphological and optoelectrical properties by employing X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HRTEM), photoluminescence, electron spin resonance (ESR) analysis and electrochemical impedance spectroscopy (EIS). The X-ray powder diffraction (XRD) result supports the good crystallinity of the fabricated nanohybrid with co-existence of pure phases of γ-Al 2 O 3 and CdO nanoparticles (NPs). The nanohybrid was tailored to narrow down the bandgap to visible-light region. The bandgap energy obtained by UV–visible diffuse reflectance spectroscopy (DRS) for CdO/Al 2 O 3 nanocomposite (NCs) was 2.95 eV. The Brunauer-Emmett-Teller (BET) surface area analysis shows porosity of material with high surface area. During photocatalysis, e- from CdO migrates to defect levels of Al 2 O 3 that facilitated charge separation. The kinetic rate of degradation of methylene blue (MB) by NCs was 3.5 and 14 times higher than CdO and Al 2 O 3 respectively. The performance was optimized and it showed good reusability. In addition, the multiple applications of the CdO/Al 2 O 3 were evaluated by testing the bactericidal activity. The nanohybrid posed high growth inhibition activity towards both gram positive and negative bacterial strains. The maximum colour removal (97.3%) and high mineralization (87%) was verified by UV–visible and total organic carbon (TOC) measurements. This promotes the nanohybrid to act as a better candidate for environmental remediation and disinfectant applications. [ABSTRACT FROM AUTHOR]

The present study highlighted the evaluation of visible-light-driven catalytic efficiency of ZnFe 2 O 4 decorated CeO 2 nanocomposite (CeO 2 /ZnFe 2 O 4 NCs) fabricated by chemical co-precipitation method for degradation of methylene blue (MB) dye. HRTEM, SEM, and SAED confirmed it to be spherically shaped with polycrystalline nature and chemical states being analyzed using X-ray photoelectron spectroscopy. Kubelka-Munk plot showed the deviation in band gap energy of ZnFe 2 O 4 (2.11 eV) and CeO 2 (3.18 eV) to be 2.18, 2.38, and 2.49 eV for NCs-1:2, 2:1, and 1:1, respectively. The visible-light-driven catalytic activity of NCs-2:1 was determined to be 90.48% in comparison with NCs-1:2 (77.19%) and NCs-1:1 (76.84%). The apparent degradation constant of MB by NCs-2:1 was determined to be 0.011 min−1 that is 1.57 and 2.75 folds greater than their individual counterparts, ZnFe 2 O 4 (0.007 min−1) and CeO 2 (0.004 min−1) respectively. The degradation process professes the pseudo-first order kinetics wherein the generation of . OH prompted by NCs enhanced the degradation of MB under visible light irradiation with a reusable efficiency of 92.48%. The vital role of CeO 2 /ZnFe 2 O 4 NCs-2:1 is affirmed with outcomes from this study and it elicited an effective potential to be a photocatalyst to eliminate water contaminants. • CeO 2 /ZnFe 2 O 4 NCs was synthesized by simple chemical co-precipitation method. • The NCs showed efficient photocatalytic activity of 90.48%. • The photo-generated . OH radicals played the major role in degradation. • The NCs exhibited excellent structural stability and reusability. • Reusable efficiency of NCs was 92.48% after sixth consequent cycle. [ABSTRACT FROM AUTHOR]

Binary p-n heterojunction of ZnFe 2 O 4 /SnS 2 nanocomposite (NCs) was constructed by sonochemical assisted technique for enhanced visible light induced photocatalytic performance. The narrow bandgap of 2.21 eV facilitated the photocatalyst be to active under visible-light irradiation. The rate of photodegradation of methylene blue (MB) dye by optimized-NCs ratio was observed to be remarkable with multifold enhancement than pristine ZnFe 2 O 4 and SnS 2. The interfacial contact enforces an internal electric field dependent directional charge migration which hinders charge recombination that was verified by reduced photoluminescence intensity in NCs. The degradation process was found to follow pseudo-first order kinetics. The major ROS involved in the photodegradation process were found to be hydroxyl (.OH) and superoxide (.O 2 -) radicals which were identified through the scavengers assay. The NCs were subjected to six consecutive cycles in order to test its structural stability and reusability. This work provides guidance for rational design of heterojunction with superior activity and it reflected the potential of ZnFe 2 O 4 /SnS 2 NCs as a promising photocatalyst to remove toxic pollutants from the aqueous bodies. • ZnFe 2 O 4 /SnS 2 NCs was synthesized by simple chemical co-precipitation method. • The NCs showed efficient photocatalytic activity of 91.78%. • The major reactive species involved in the degradation was . OH and . O 2 −. • The structural stability and the reusability were studied. • Reusable efficiency of ZnFe 2 O 4 /SnS 2 NCs-60 was 99.68% after sixth consequent cycles. [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 novel AgFeO 2 –ZnO nano-photocatalyst with magnetic recyclability was prepared via facile sono-chemical route. HRTEM analysis showed intimate contact of AgFeO 2 nanospheres on ZnO NPs. UV–vis-DRS verified excellent light harvesting capacity in visible-light region. XPS was used to verify chemical composition and valence states (Ag3d, Fe2p, O1s, and Zn2p). Peaks corresponding to tetrahedral/octahedral M−O bonds were noted in FTIR. The photocatalytic activity for dye degradation was boosted 10.5 times in AgFeO 2 –ZnO nanocomposites (NCs) relative to pristine ZnO. The high surface area of NCs provided more reactive sites that enhance dye degradation. Trapping experiments indicated that h+ and ·OH played a major role. The growth of Escherichia coli and Bacillus subtilis was inhibited to great extend on exposure with NCs. Hence, the investigation reports AgFeO 2 –ZnO NCs can be used as an effective environmental remediation tool through photocatalysis and found to be active as a good antibacterial agent. [ABSTRACT FROM AUTHOR]

Mn-based photocatalyst and antimicrobial agent was synthesized by ultrasonic-assisted co-precipitation method by keeping MnO 2 as active compound and Al 2 O 3 was adopted as catalyst support. XRD and HRTEM analysis verified the co-existence of MnO 2 and Al 2 O 3 and the crystalline nature of NCs. The XPS and EDAX revealed the chemical states of elements namely Mn2p, Al2p and O1s. The presence of Mn–O and Al–O–Al bonds were noted through FTIR. The photon absorption ability of NCs in visible region was favoured by the energy bandgap of 2.51 eV. Photoluminescence revealed that the charge carriers in NCs showed an improvement in life time. The NCs exhibited enhanced photocatalytic effect due to its synergetic effect and the photocatalytic performance can be ordered as MnO 2 /Al 2 O 3 > MnO 2 > Al 2 O 3. The enhancement in photocatalysis rate in NCs was attributed by the formation of heterostructure and it prevent the recombination of charge carriers. The OH· radical was the dominant species in dye degradation. The NCs showed high photostability and recyclability, and almost same photocatalytic activity preserved even after sixth recycle. In addition to that, the antimicrobial activity of MnO 2 /Al 2 O 3 was demonstrated to be efficient in their action against the strains of gram positive and gram negative bacteria than that of the individual MnO 2 and Al 2 O 3 NPs. Thus, this multifunctional MnO 2 /Al 2 O 3 can be used as an efficient candidate for the photocatalytic degradation of toxic dyes and an antimicrobial agent. • MnO 2 –Al 2 O 3 NCs was constructed by chemical co-precipitation method. • The rate of photodegradation of MB by NCs was 6 times higher than Al 2 O 3 NPs. • Photoluminescence study revealed the reduced recombination rate of e−/h+ pairs. • The OH· radical was the dominant species in dye degradation. • The nanohybrid exhibited excellent antibacterial activity. [ABSTRACT FROM AUTHOR]

Photocatalysis is one of the versatile processes widely applied for the treatment of environmental water pollutant. In this work, NiS/Ag 2 MoO 4 heterostructured nanocomposite (NCs) was synthesized via ultra-sonication assisted and chemical co-precipitation methods. The prepared particle was characterized using HR-TEM, SAED, EDAX, UV–vis DRS, XRD, nitrogen adsorption and desorption, PL, and XPS. The band gap of NCs was found to be 2.77 eV which facilitates the enhanced activity in visible region. The heterostructure formation between NiS and Ag 2 MoO 4 have induced the separation of charges efficiently which caused the increase in photocatalytic performanc. The photocatalytic study reveals that NiS/Ag 2 MoO 4 enhanced the degradation of MB (90.8%) relative to individual NiS and Ag 2 MoO 4. The MB degradation followed pseudo first order reaction (R2 < 0.955). The radical trapping experiment confirmed that the major species involved in photodegradation process were superoxide and hydroxyl radicals. The prepared photocatalyst was structurally stable and highly reusable as confirmed by cycles test. Also, the NCs showed excellent anti-bacterial property. The results confirmed the good potentiality of NCs to degrade the organic dye compounds and as a good anti-bacterial agent. • The NiS/Ag 2 MoO 4 exhibited enhanced photocatalytic degradation of MB dye under visible light radiation. • The mechanism of photo-degradation activity by NiS/Ag 2 MoO 4 was elucidated. • NiS/Ag 2 MoO 4 exhibited good photostability. • Excellent antibacterial activity shown by NiS/Ag 2 MoO 4 against E. coli and B. subtilis. [ABSTRACT FROM AUTHOR]

• Bi 2 MoO 6 /Ag 2 MoO 4 nanocomposite was synthesized with a tuned band gap of 2.89 eV. • Bi 2 MoO 6 /Ag 2 MoO 4 nanocomposite exhibited 91.8% degradation of MB. • Bi 2 MoO 6 /Ag 2 MoO 4 nanocomposite demonstrates good photostability, reusability and antimicrobial activity. • The key reactive species involved in the photocatalytic degradation process was OH. The novel Bi 2 MoO 6 -Ag 2 MoO 4 nano-photocatalyst was prepared via facile sono-chemical route. Bi 2 MoO 6 -Ag 2 MoO 4 nanocomposite was characterized by high-resolution transmission electron microscopy (HR-TEM), fourier transverse infrared spectroscopy (FTIR), X-ray diffraction (XRD), BET surface area analyzer, photoluminescence (PL), X-ray photoelectron spectroscopy and UV–visible diffuse reflectance spectroscopy. XRD and SAED pattern shows that the particles were crystalline in nature. The formation of heterojunction with tuned band gap of 2.89 eV enhanced the photocatalytic performance of nanocomposite under visible light irradiation. Bi 2 MoO 6 -Ag 2 MoO 4 nanocomposite followed the pseudo-first order kinetic and it showed high correlation coefficient value (R2 > 0.95), and it fitted well to the Langmuir–Hinshelwood model. Bi 2 MoO 6 -Ag 2 MoO 4 nanocomposite exhibited 91.8% degradation which was highly effective than individual Ag 2 MoO 4 (54.66%) and Bi 2 MoO 6 (58.6%). The radical trapping study reveals the key reactive species involved in photocatalytic degradation process such as .OH. The Bi 2 MoO 6 -Ag 2 MoO 4 nanocomposite was found to be highly reusable for the degradation of MB dye by showing 91.8% degradation efficiency after 6th cycle. Antimicrobial activity of the Bi 2 MoO 6 -Ag 2 MoO 4 nanocomposite was superior when compared with Ag 2 MoO 4 and Bi 2 MoO 6 nanoparticles. The prepared nanocomposite proved a robust alternative as a solar radiation driven photocatalyst and it also acts as an antimicrobial agent for the treatment of environmental water. [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]

Photocatalysis is the versatile process that can be applied for water treatment, environmental remediation etc. A facile sonochemical-co-precipitation technique was adopted to prepare CuFe 2 O 4 decorated ZnO heterojunction nanocomposites (NCs). The characterization was done using UV–vis-DRS, TEM, EDAX, SAED, XRD, BET, PL and FTIR. The TEM reveals that the fabricated NCs were cubic in shape. The XRD and SAED analysis confirmed the crystalline nature of prepared NCs. The NCs band gap was determined to be 2.34 eV that facilitates enhanced performance of photocatalysis in visible region. The photocatalytic activity of NCs when irradiated with visible light was evaluated on basis of methylene blue (MB) dye degradation. The t½ for the degradation of 10 mg/L dye by 3 mg of NCs by photocatalysis was determined to be 77 min. The apparent rate constant of NCs was 4–5.1 times higher in NCs than CuFe 2 O 4 and ZnO respectively. At the end of 6th recycle, the XRD pattern and NCs photocatalytic activity were retained the same as 1st that denotes the high stable nature of NCs. The results indicate the enhanced activity of fabricated NCs relative to individual ZnO and CuFe 2 O 4 NPs. A possible photocatalysis mechanism was elucidated using charge carriers and free radicals scavengers. It was evident that ⋅OH radical and holes play the major role in dye degradation. The NCs acted as excellent antimicrobial agent against Bacillus subtilis and Escherichia coli. Hence, the investigation reports that ZnO@CuFe 2 O 4 NCs can be used as an efficient photocatalyst and as an antibacterial agent. • p-n type ZnO@CuFe 2 O 4 NCs was synthesized by chemical co-precipitation with ultrasonic assisted method. • The NCs were characterized by UV–vis-DRS, TEM, EDAX, SAED, XRD, BET, PL and FTIR analysis. • The photocatalytic activity was enhanced by 4–5.1 times than individual counter parts. • The mechanism of degradation was elucidated based on scavengers' responses. • The particles exhibited excellent antibacterial activity. [ABSTRACT FROM AUTHOR]

Photocatalysis is reported to be an effective method for the removal of organic toxic pollutant present in the environmental waters and industrial effluents. NiMoO 4 /Ag 2 MoO 4 nanocluster (NMO/AMO) was synthesized for its multiple applications such as photocatalytic property under visible light irradiation and antimicrobial activity. The structure and the morphological features of NMO/AMO was determined by high-resolution transmission electron microscope (HRTEM), X-ray diffraction (XRD), fourier-transfer infrared spectroscopy (FTIR), photoluminescence (PL), energy dispersive X-ray spectroscopy (EDAX), BET isotherm and UV–visible diffuse reflectance spectroscopy (UV–vis DRS). EDAX and XRD confirm the formation of NMO/AMO and its crystalline nature. PL of NMO/AMO showed that the intensity was lower than individual AMO and NMO, which indicates its reduced recombination of charge carriers. Effective photodegradation of methylene blue (MB) dye was noticed by using NMO/AMO. NMO/AMO nanocluster showed 84.5% degradation at 1st cycle and 82.2% at 6th cycle which confirm its reusability. Here, the photocatalytic activity was enhanced mainly due to h+ and OH., and it follows pseudo first order kinetics. The antimicrobial activity of NMO/AMO nanocluster, AMO and NMO nanoparticles were performed against Escherichia coli and Bacillus subtilis at different concentrations. The NMO/AMO nanocluster showed effective antimicrobial activity than the individual AMO and NMO nanoparticles. Hence, the fabricated NMO/AMO nanocluster could be used as an effective candidate for high potential environmental application such has industrial water treatment, antibacterial agent etc. • NiMoO 4 /Ag 2 MoO 4 nanocluster was synthesized by sono-chemical coprecipitation method. • The NiMoO 4 /Ag 2 MoO 4 nanocluster showed outstanding visible-light photocatalytic activity. • NiMoO 4 /Ag 2 MoO 4 nanocluster demonstrates good photostability and reusability. • The hydroxyl radical and proton was responsible for the enhance photocatalytic activity. [ABSTRACT FROM AUTHOR]

Mercury has been considered as the most toxic metal pollutants that pose lethal threat to environment and the human health at small concentrations. Thus, the development of a rapid, inexpensive and simple technique for Hg2+ ion detection in real aqueous samples is paramount. The present study reported a colorimetric assay for sensing Hg2+ ion using Cu sensitized Ag-dextran nanocomposite (NCs) in presence of tyrosine. The particle was characterized by UV–visible (vis) spectrophotometer, zeta sizer, HR-TEM, particle size analyzer, FT-IR, EDAX and XRD. The NCs possessed a hydrodynamic diameter of 26 ± 1.4 nm and − 32.21 ± 3 mV was the zetapotential value. The colour of Ag/Cu NCs was brownish yellow due to the LSPR band centred at 408 nm. An appreciable colour change was observed from yellowish brown to colourless after interaction with Hg2+ ion. A good linearity existed in the correlation curve between the absorbance value (ℷ = 408 nm) and the Hg2+ ion concentrations (20 nM – 100 nM). A simple, low cost paper-strip based sensor of Ag/Cu NCs used as an real time portable Hg2+ detection. The influence of other metal ions, pH (5.0 to 9.0), salinity (0.1–0.8%) and temperature (15–50 °C) for the Hg2+ detection was also investigated. The NCs exhibits high specificity, sensitivity and stability towards the Hg2+ detection at low nano molar level. Additionally, the NCs exhibited excellent MB degradation under irradiation of visible light and it also showed antimicrobial activity against B. subtilis and E. coli. The study demonstrated the application of Cu sensitized Ag-dextran NCs in detection, photocatalysis, and as an antimicrobial agent. Unlabelled Image • The prepared probe was selective towards detection of Hg2+ in real aqueous sample. • Ag Cu nanocomposite showed specificity in detection in the presence of tyrosine. • A simple, low-cost paper strip method was developed to detect Hg2+. • Effect of pH, temperature, salinity and interference of other metal ions were studied. • The particles showed efficient photocatalytic and anti-microbial activity. [ABSTRACT FROM AUTHOR]