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The present work presented a novel approach for the degradation of binary Eosin B (EB) and Malachite green (MG) dyes and single dyes using undoped and potassium doped tin oxide (K-SnO2) nanoparticles (NPs) under UV irradiation. The NPs were synthesized using the co-precipitation method. Studies based on multi-dye systems, are hardly available and do not give any detailed reasons for different behaviors of dyes towards the photocatalyst and of the level of degradation. The prepared nanomaterials were identified through Thermal Gravimetric Analysis (TGA), energy dispersive X-ray (EDX), scanning electron microscopy (SEM), UV–Visible (UV–VIS), X-ray diffraction analysis (XRD), and Fourier transform infrared (FTIR) spectroscopy. SnO2 and K-SnO2 optical band gaps were calculated to be 3.5 eV and 3.7 eV respectively. The points of zero charge for both SnO2 and K-SnO2 were calculated to be 4. The XRD results showed that the SnO2 and K-SnO2 particles were crystalline, with mean sizes of 17.13 nm and 10 nm, respectively. The maximum degradation efficiency of the catalyst for MG dye degradation was 99% and that of EB was 77%. [ABSTRACT FROM AUTHOR]

Perovskites overtaking simple metal oxides as solar light harvesting material due to their excellent photocatalytic efficiency and superior stability. An efficient visible light responsive, K 2 Ba 0.3 Cu 0.7 O 3 single perovskites oxides (SPOs) photocatalyst was fabricated by a facile hydrothermal method. The fabricated SPOs was characterized by various techniques. SEM analysis confirm the cubic morphology of SPOs, the average length and diameter of SPOs were 27.84 and 10.06 μm calculated from SEM images. FT-IR analysis confirmed the presence of M-M and M − O bonds. EDX showed prominent peaks of the constituent elements. The average crystallite size of SPOs calculated by Scherrer and Williamson-Hall equation was 14.08 and 18.47 nm respectively. The optical band gap value lies in visible region of spectrum (2.0 eV) determined from the Tauce's plot. The fabricated SPOs was applied for photocatalytic degradation of methylene blue (MB) dye. Maximum degradation 98.09% of MB was achieved at 40 min irradiation time, 0.01 g catalyst dose, 60 mg L−1 MB concentration and pH 9. The photocatalytic degradation of MB follows first order kinetic. RSM modeling of MB removal was also caried out. Reduce quadratic model was best fitted model having F-value = 300.65, P-value = < 0.0001,R2 = 0.9897, predicted R2 = 0.9850 and adjusted R2 = 0.9864. [Display omitted] • Cubic structured single perovskite microplates perovskites visible light-responsive photocatalyst production. • Structural and morphological characteristics were scrutinized using advanced techniques. • Highly efficient photocatalytic degradation of methelyne blue (MB) dye under sunlight irradiation. • The quadratic model was the best-fitted model of response surface methodology. [ABSTRACT FROM AUTHOR]

The manganese oxide (MnO 2 and iron-doped manganese oxide (Fe–MnO 2) nanoparticles (NPs) with reduced band gap (Eg) were fabricated through the co-precipitation process. They used to degrade Indigo Carmine (IC) and Rhodamine B (RB) binary mixture in an aqueous medium under solar light irradiation. From FT-IR, the twisting modes of the Mn–O bond and the stretching vibrations of the Fe–Mn–O 2 bond were confirmed from the peaks observed at 480 cm−1,584 cm−1,675 cm−1, and 900 cm−1, 1150 cm−1, and 1200 cm−1 respectively. The MnO 2 has an optical band gap of 3.2 eV, which was decreased to 3 eV in Fe–MnO 2. The zero charge (PZC) point was 8 for Fe–MnO 2 and 7 for MnO 2. The BET surface area for Fe–MnO2 was 398 m2/g, relatively higher than MnO2 particles, having a surface area of 384 m2/g. The average crystallite sizes calculated from Scherer formulae were 37 nm for MnO 2 and 31 nm for Fe–MnO 2 NPs. SEM confirmed the irregular morphology of the prepared particles. It was analyzed that agglomeration occurs in MnO 2 than the Fe–MnO 2. The maximum degradation of IC dye was 99%, and that of RB was 98% at the optimum conditions. The data were best fitted to second-order kinetics. [Display omitted] • Visible light-triggered and recyclable iron-doped manganese oxide (Fe–MnO 2) NPs as photocatalyst. • Morphological and structure tailoring studies was done through advanced techniques. • Photocatalytic degradation of Indigo Carmine (IC) and Rhodamine B (RB) single and binary mixture. • Response surface methodology (RSM) for optimization of degradation process. [ABSTRACT FROM AUTHOR]