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Environmental pollution and energy scarcity is a major issue of the current scenario which forbear the progress of developing world. To overcome these problems towards a sustainable future, the utilization of sunlight by means of photocatalysis can be regarded as a best and suitable pathway. To validate this purpose, design and development of efficient heterogeneous photocatalyst for harvesting solar energy should be the major research concern for scientific community. In this regard herein, we have prepared a series of stable and efficient CoTiO 3 /UiO-66-NH 2 p-n junction mediated heterogeneous photocatalyst by hydrothermal method. The functionalised linker of UiO-66-NH 2 provided an intimate interfacial contact with CoTiO 3 by Co/TiON ionic interaction, as proved by HRTEM and XPS analysis. Moreover the inverted V-shaped Mott-Schottky plot confirmed the junction formation in the optimised CoTiO 3 /UiO-66-NH 2 material. In addition, EIS and PL analysis also provides sufficient evidence about the hindrance of active species recombination in composite as a result of p-n hetero junction. LC-MS characterization technique traces the assorted intermediate species produced in the course of photodegradation of Norfloxacin and confirms its complete degradation to corresponding CO 2 , H 2 O and NH 4 + by the optimised CoTiO 3 /UiO-66-NH 2 . The highest photo-catalytic activity obtained towards Norfloxacin degradation is 90.13% and H 2 production is 530.87 µmol in 1 h. The enhanced photo-catalytic reaction follows Type-II p-n hetero junction charge transfer mechanism and thus, paves a new way to design MOF based heterojunction photocatalyst for diverse photo catalytic performance., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Fusion of heterogeneous photocatalysts with conducting polymers has paid a rising stratagem in the field of photocatalysis owing to its biocompatibility and environment friendliness. In this work a series of polypyrrole (PPY) sensitized zinc ferrite/graphitic carbon nitride (ZFCN) n-n heterojunction (ZFCN@10PPY, ZFCN@20PPY, and ZFCN@30PPY) nanocomposite were fabricated by in-situ polymerization method. Due to low band gap of polypyrrole, it behaves as a photo-sensitizer, supplies surplus numbers of electrons to ZnFe 2 O 4 /g-C 3 N 4 n-n heterojunction and improves the photocatalytic performance. The fabricated ZFCN@20PPY exhibits highest photocatalytic activity in comparison to others nanocomposites. The superior photocatalytic performance of ZFCN@20PPY was ascribed to the tunable band structure, synergistic effect of broad absorption upto NIR region, delayed electron-hole recombination and efficient charge transfer across the junction interface which has been well confirmed from UV-Vis DRS, PL and EIS measurement. Further the photocatalytic activity of ZFCN@20PPY was supported by both n-type and p-type photocurrent density i.e. 2.4 and 3.9 mA/cm 2 respectively. ZFCN@20PPY shows good photocatalytic performance towards ciprofloxacin degradation (92%) and generation of hydrogen energy (567 μmol). Along with pollutant degradation and energy production ZFCN@20PPY also shows its potential towards antibacterial activities against human pathogenic bacteria like Escherichia coli. These newly designed polymer sensitized n-n heterojunction may offer a promising strategy for maximum light absorption and be authoritative in meeting the environmental claims in the future., (Copyright © 2019 Elsevier Inc. All rights reserved.)

The production of Hydrogen energy through the splitting of water is a promising pathway for clean environment and sustainability. Herein we have synthesized a series of ZnFe 2 O 4 (ZFO)@Reduced Graphene Oxide (RGO) nanocomposites by hydrothermal followed by calcination method and studied its application towards hydrogen energy production and ciprofloxacin degradation. Powder X-ray diffraction (XRD) study and X-ray photoelectron spectroscopy (XPS) analysis indicate the good crystallinity and suitable chemical environment for the photocatalytic process. Among all the samples, ZFO@3%RGO showed 73.4% of CIP degradation under solar irradiation of 1 h, which is 1.67 times higher than that of pure ZFO nanoparticles. CIP degradation process follows first order kinetics with a good rate constant of 0.021 min -1 which is 2.3 times greater than ZFO. The photocatalyst ZFO@3%RGO illustrated maximum H 2 energy production i.e. 410.32 μmol/h, which is 1.35 times more than that of neat ZFO nanoparticles. ZFO@3%RGO demonstrates the highest photocurrent density of 0.6 mA/cm 2 under light illuminations, which is 250 times superior to that of the pristine photocatalyst. Bode phase analysis confirmed that ZFO@RGO shows 13 times higher charge separation efficiency in comparison to neat ZFO. The best photocatalytic activity of ZFO@3%RGO nanocomposite is due to its high light absorption capacity, low photogenerated exciton recombination, high electron-hole separation, and high photocurrent density., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Development of highly efficient robust catalyst for pollutant abetment still remains an ongoing scientific challenge in the field of visible light driven photocatalysis. In this work a series of ZnFe 2 O 4 (ZFO)/carbon derivatives (ZFO@CNT, ZFO@GO, ZFO@Fullerene) nanocomposite were fabricated by one-pot hydrothermal method followed by calcination. The detail anatomical featured such as crystal geometry, morphology, elemental composition, light absorption performance, electron-hole recombination properties and photocurrent density were characterized by XRD, SEM, HRTEM, XPS, UV-Vis DRS, PL and electrochemical analysis respectively. The photocatalytic performances of ZFO@carbon nanocomposites were studied for the degradation of antibiotics (Norfloxacin) and hexavalent Chromium under open sun light illumination and the obtained results suggested that loading of carbon derivatives of ZFO nanoparticles enhance the visible light absorption capacity and excitation separation efficiency. Among the fabricated composites, ZFO@CNT exhibits the highest activity in comparison to other nanocomposites. The highest activity of ZFO@CNT is due to low photoexcited electron-hole recombination and high charge transfer properties of ZFO@CNT as confirmed via PL and impedance measurement. Further, the fabricated ZFO@CNT nanocomposite exhibited highest photocurrent density i.e. 2.25 mA/cm 2 which was 225 times higher than that of neat ZFO. The optimal photocatalytic efficiency was shown by ZFO@CNT i.e. 91.36% degradation of 50 ppm norfloxacin and 82% reduction of 10 ppm Cr (VI) in 90 min and 60 min respectively under solar light irradiation., (Copyright © 2019. Published by Elsevier Inc.)