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Visible light active, highly stable, nontoxic, and efficient photocatalysts based on 1 %, 3 %, and 5 % Mn@Co3O4 were synthesized and functionalized with reduced graphene oxide. The X-rays diffraction (XRD) spectroscopy and FT-IR spectroscopy were employed for structural and functional group studies. Under visible light irradiation, photocatalytic activities of 1 %, 3 %, and 5 % Mn@Co3O4/rGO nanocomposites were studied for the degradation of organic pollutant methylene blue. Almost 85.4 %, 90.2 %, and 93.4 % degradation of methylene blue were observed after 80 min with 1 % Mn@Co3O4/rGO, 3 % Mn@Co3O4/rGO, and 5 % Mn@Co3O4/rGO respectively. The prepared nanocomposites followed pseudo-first-order kinetic studies. Among all samples, the 5 % Mn@Co3O4/rGO showed maximum degradation of 93.4 % in 80 min. Moreover, 5 % Mn@Co3O4/rGO nanocomposite maintained its excellent dye degradation ability even after three cycles. [ABSTRACT FROM AUTHOR]

Sol–gel approach was employed for synthesis of nickel aluminate (NiAl 2 O 4 , NA), and silver doped nickel aluminate (Ag-NiAl 2 O 4 , AgNA) nanomaterials. The ultra-sonication approach was employed to synthesize their composite with graphitic carbon nitride (Ag-NiAl 2 O 4 @g-C 3 N 4 , AgNA@gCN) for degradation of organic effluents such as methylene blue (MB), crystal violet (CV), and benzoic acid (BA) photocatalytically. The synthesized photocatalysts were characterized by various techniques like X-rays diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and UV–visible spectroscopy. XRD confirmed the formation of doped and un-doped NiAl 2 O 4. The crystallite size of as-prepared nanomaterials was found out less than 13 nm. FT-IR technique was used for functional groups detection present in synthesized photocatalysts. The surface morphology of fabricated nanomaterials was investigated via SEM. The thermal stability of prepared samples was investigated via TGA. Optical analysis was carried out by UV-Visible spectrophotometer. NA and AgNA exhibited the bandgap energy of 3.50 eV, and 2.88 eV respectively. The photocatalytic efficiency of fabricated samples was analyzed under solar light. AgNA@gCN exhibited 85.26% degradation of MB, 83.87% of CV, and 68.46% of BA under sunlight. The overall removal (%adsorption + % degradation) of MB, CV, and BA by AgNA@gCN were 99.67%, 98.54%, and 76.91% respectively. The scavenging experiment was also performed to find out the most photoactive species involve in the degradation of organic effluent photocatalytically. Hydroxyl radicals are the mainly photoactive species responsible for the photocatalytic experiment. Simple facile route was adopted to prepare Ag-NiAl 2 O 4 @g-C 3 N 4 ; a new photocatalyst, that was utilized for photodegradation of various organic effluents under solar light irradiation. [Display omitted] • Simple facile route was adopted to prepare Ag.NiAl 2 O 4 @g-C 3 N 4 , a new photocatalyst. • Photodegradation of various organic effluents by Ag-NiAl 2 O 4 @g-C 3 N 4 was studied. • Mechanistic investigation of degradation has also been discussed. [ABSTRACT FROM AUTHOR]

Magnesium ferrite (MgF), copper doped magnesium ferrite (CMgF), and their composite with rGO sheets were used to study the degradation of the organic pollutants and to perform antibacterial activity. The photocatalysts were prepared by the co-precipitation technique and characterized using X-rays diffraction (XRD), scanning electron microscopy (SEM) UV–visible, and fourier transfrom infrared microscopy (FT-IR), and photoelectrochemical analysis. The structure of the nanomaterials was confirmed via XRD. The functional group detection was carried out via FT-IR spectroscopy. The SEM technique was used to confirm the surface morphology of the prepared nanocatalysts. UV–Visible spectroscopy was used to measure the absorbance during the degradation experiment. The percentage photodegradation by CMgF@rGO of methylene blue was 92.4%, and that of benzimidazole was 50%. CMgF@rGO also showed better antibacterial activity against bacterial strains of Klebsiella pneumonia and Staphylococcus aureus. The rGO layers can enhance the photodegradation efficiency of copper doped magnesium ferrite due to an increase in surface area. The EIS study revealed that CMgF@rGO illustrated 2.59 and 1.57 times less charge transfer resistance than MgF and CMgF samples. The CMgF@rGO composite separately showed 9.7-fold and 3.9-fold greater transient photocurrent response than MgF and CMgF samples. A scavenging experiment was carried out to determine the most reactive species; and hydroxyl radicals were found to be highly active species, and electrons were the least reactive species. [Display omitted] [ABSTRACT FROM AUTHOR]

• Wet chemical routes are used for the synthesis of CuBi 2 O 4 and Bi 2 S 3. • Ultrasonication route is used to synthesize CuBi 2 O 4 /Bi 2 S 3 and CuBi 2 O 4 /Bi 2 S 3 /rGO. • XRD and FTIR confirmed the structural and spectral properties. • CuBi 2 O 4 /Bi 2 S 3 /rGO ternary composite showed excellent catalytic activity. Water pollution is the major issue to be resolved nowadays. To overcome water pollution, the use of nanotechnology proved to be an emerging field. In this project, CuBi 2 O 4 (CB-1) and Bi 2 S 3 (CB-2) were prepared by simple hydrothermal and chemical precipitation routes respectively. To enhance the effectiveness of the photocatalyst, the synthesis of CuBi 2 O 4 /Bi 2 S 3 (CB-3) and CuBi 2 O 4 /Bi 2 S 3 /rGO (CB-4) nanocomposite were carried out by ultrasonication method. Different physiochemical techniques were used to characterize the as prepared catalysts. The photocatalytic activity of fabricated catalysts was then checked for methylene blue degradation. Among all the samples, CB-4 showed the best photocatalytic performance (90.47 %) as it has low band gap energy than other fabricated materials. Therefore, the fabricated nanocomposite can be employed as a promising photocatalytic material for future use. [ABSTRACT FROM AUTHOR]

• Novel Tb x Bi 1-x FeO 3 nanoparticles decorated over carbon nanotubes were synthesized. • XRD analysis confirmed the structure of synthesized samples. • Tb x Bi 1-x FeO 3 /CNT showed 63.5 % degradation of crystal violet. • Tb x Bi 1-x FeO 3 nano-particles decorated on CNTs demonstrated synergistic effect of photocatalytic activity and adsorption. This study aims to investigate the usage of Tb x Bi 1-x FeO 3 (x = 0.0, 0.020) composite with CNTs as photocatalyst for the photodegradation of pendimethalin and crystal violet dye. Using the wet chemical and ultra-sonication method, uniformly sized BiFeO 3 , Tb-doped BiFeO 3, and Tb-doped BiFeO 3 /CNT composite samples were prepared. Powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and Scanning electron microscope (SEM) were utilized for characterization purpose. The crystallite size of the BiFeO 3 particles with cubic spinel structure was observed to be 25.2 nm. Following the pseudo-first-order kinetics, the as-synthesized photocatalyst was found to have excellent photocatalytic degradation efficiency for the degradation of crystal violet and pendimethalin. Tb-BiFeO 3 /CNTs degrade pendimethalin by 55% and crystal violet by 63.5% with better rate constants than its counterparts. The better photocatalytic activity was displayed via Tb- BiFeO 3 /CNT composite than other prepared samples due to the incorporation of CNTs which provides greater surface area for photodegradation of harmful pollutants. [ABSTRACT FROM AUTHOR]

• NiFe 2 O 4 was successfully synthesized via co-precipitation route. • Various physio-chemical techniques were employed to characterize the prepared samples. • The prepared photocatalysts were used for the degradation of pendimethalin under sunlight. • rGO based nanocomposite showed maximum degradation efficiency. • Gd doping and insertion of rGO sheets help to enhance the photo-degradation ability of nickel ferrite. NiFe 2 O 4 (F-1) and rare earth metal (Gd) doped NiFe 2 O 4 (F-2) were prepared via a co-precipitation approach. Gd-NiFe 2 O 4 @rGO (F-3) was prepared via an ultrasonication route for the degradation of pendimethalin under sunlight. The structural confirmation of as-fabricated samples was done via XRD. The Tauc plot of F-1 showed a bandgap energy of 2.79 eV and F-2 exhibited a bandgap energy of 2.63 eV. The optical band gap was lowered due to the presence of rare-earth metal ions. NiFe 2 O 4 and Gd-NiFe 2 O 4 showed 48.88 %, and 61.11 % degradation of pendimethalin. Gd-NiFe 2 O 4 @rGO nanocomposite showed the highest degradation efficiency. It exhibited 84.44 % degradation of pendimethalin in 140 min at the rate of 0.01 min−1. The reason for the greater activity is due to the insertion of rare earth (Gd) ions and rGO sheets in the nickel ferrite. The doping with rare earth metal ions lowers the recombination of electrons and holes which was further supported by the addition of carbonaceous material. The surface area of the nickel ferrite was improved by rGO sheets and in turn more active sites were formed on the surface of the catalyst which fastens the rate of reaction. [ABSTRACT FROM AUTHOR]

The present study investigates the photocatalytic activity of NiCoPrFe 2 O 4 and Cd-NiCoPrFe 2 O 4 synthesized by the self-ignition sol-gel process. NiCoPrFe 2 O 4 @CNTs was prepared via ultrasonication approach. Methyl violet was used as a dye to examine the photodegradation activities of synthesized photocatalysts under visible light. The spinel crystalline structure is confirmed by XRD. The morphology of the as prepared samples was observed via scanning electron microscopy. NiCoPrFe 2 O 4 , Cd-NiCoPrFe 2 O 4 , and NiCoPrFe 2 O 4 @CNTs showed 55.46%, 78.29%, and 85.96% percentage degradation of methyl violet respectively. The photocatalytic performance of CNT based nanocomposite is found to be increased due to the enhanced charge separation property of CNT. • The sol-gel method was used for the preparation of NiCoPrFe2O4. • XRD and FTIR corroborate the structure and composition of elemental features. • SEM analysis confirms the morphology of the material. • NiCoPrFe2O4@CNT composite had shown excellent result is the photo-degradation of methyl violet. [ABSTRACT FROM AUTHOR]