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Visible-light-driven photo-fenton-like catalytic activity and photoelectrochemical (PEC) performance of nitrogen-doped brownmillerite KBiFe2O5 (KBFO) are investigated. The effective optical bandgap of KBFO reduces from 1.67 to 1.60 eV post N-doping, enabling both enhancement of visible light absorption and photoactivity. The photo-fenton activity of KBFO and N-doped KBFO samples were analysed by degrading effluents like Methylene Blue (MB), Bisphenol-A (BPA) and antibiotics such as Norfloxacin (NOX) and Doxycycline (DOX). 20 mmol of Nitrogen-doped KBFO (20N-KBFO) exhibits enhanced catalytic activity while degrading MB. 20N-KBFO sample is further tested for degradation of Bisphenol-A and antibiotics in the presence of H2O2 and chelating agent L-cysteine. Under optimum conditions, MB, BPA, and NOX, and DOX are degraded by 99.5% (0.042 min-1), 83% (0.016 min-1), 72% (0.011 min-1) and 95% (0.026 min-1) of its initial concentration respectively. Photocurrent density of 20N-KBFO improves to 8.83 mA/cm2 from 4.31 mA/cm2 for pure KBFO. Photocatalytic and photoelectrochemical (PEC) properties of N-doped KBFO make it a promising candidate for energy and environmental applications. [ABSTRACT FROM AUTHOR]

This work reports the design and development of an efficient sillenite based visible light photoactive Bi 24 Ga 2 O 39 –TiO 2 (BGT) heterostructure. Structural and morphological studies based on X-ray diffraction (XRD) and high-resolution scanning electron microscopy (HRSEM) confirm the formation of combined phase as well the overall morphology of composite BGT. Additionally, X-ray photoelectron spectroscopy (XPS) results confirm the presence of Bi3+, Ga3+, Ti4+ & O2−. The composite exhibits a shift in the absorbance edge towards visible region of electromagnetic spectrum when compared to that of TiO 2. Suitable band edge positions in the composite facilitate the formation of type-1 heterojunction enhancing visible light photocatalytic property. The photocatalytic activity is evident from photo reduction of Cr (VI) (95% reduction in 180 min). The composite also plays an improved and effective role in the degradation of persistent drug ampicillin-cloxacillin (AMC) with a rate constant of 0.02 min−1. Photocatalytic experiments conducted at different pH values showed higher performance at lower pH ∼3. Trapping experiments performed on the sample confirm the role of holes as the main active species during photocatalysis. Appreciable recyclability of BGT composite was noted with respect to AMC drug degradation. • First report of Bi 24 Ga 2 O 39 - TiO 2 (BGT) composite for photo reduction of Cr (VI). • Enhanced photoreduction achieved up to 95% reduction in 180 min, without using any co-catalyst. • The BGT was utilized to degrade the ampicillin-cloxacillin drug with a rate constant of 0.02 min−1. • Photoactivity of BGT corroborated by efficient photocurrent density (∼1.91 μA/cm2). [ABSTRACT FROM AUTHOR]

Solar hydrogen production has been successfully demonstrated with CdTe quantum dot (QD) supported porous hierarchical ZnIn 2 S 4. A reduction in effective bandgap from 2.7 eV (for ZnIn 2 S 4) to 2.56 eV (for ZnIn 2 S 4 /CdTe QD composite) was observed. An efficient charge transfer between ZnIn 2 S 4 and CdTe in the ZnIn 2 S 4 /CdTe QD composite is confirmed from Photoluminescence (PL) studies. Effective reduction in bandgap of composite heterostructure enhances the absorption in visible spectrum and generates more charge carriers, as corroborated from PEC measurements (~ 5.7 μA/cm2). In the present work 3% CdTe QDs decorated with ZnIn 2 S 4 (ZCd3) exhibits higher photocatalytic activity during degradation of Rhodamine B (RhB) dye by 94% in 35 min. An excellent photocatalytic performance of ZCd3 sample was also noted during H 2 production yielding a production rate of 1070 μmol g−1 in 3 h. It is believed that the integration of CdTe quantum dot with ZnIn 2 S 4 enhances the photocatalytic efficiency of ZnIn 2 S 4 by improving charge carrier separation and transfer. [Display omitted] • Synthesis of CdTe quantum dots (QD)/ZnIn 2 S 4 heterostructure has been carried out through one step hydrothermal route. • The effect of CdTe QD loading on ZnIn 2 S 4 lattice resulted in effective band gap reduction from 2.7 eV to 2.56 eV enableing enhanced absorption. • The degradation of organic pollutant by CdTe quantum dots (QD)/ZnIn 2 S 4 heterostructure was about 1.36 times more effective than pure ZnIn 2 S 4. • Achieved 1070 μmol g−1 of hydrogen production in 3 h of irradiation without any supporting co-catalyst. [ABSTRACT FROM AUTHOR]

Visible-light-driven photo-fenton-like catalytic activity and photoelectrochemical (PEC) performance of nitrogen-doped brownmillerite KBiFe2O5 (KBFO) are investigated. The effective optical bandgap of KBFO reduces from 1.67 to 1.60 eV post N-doping, enabling both enhancement of visible light absorption and photoactivity. The photo-fenton activity of KBFO and N-doped KBFO samples were analysed by degrading effluents like Methylene Blue (MB), Bisphenol-A (BPA) and antibiotics such as Norfloxacin (NOX) and Doxycycline (DOX). 20 mmol of Nitrogen-doped KBFO (20N-KBFO) exhibits enhanced catalytic activity while degrading MB. 20N-KBFO sample is further tested for degradation of Bisphenol-A and antibiotics in the presence of H2O2 and chelating agent L-cysteine. Under optimum conditions, MB, BPA, and NOX, and DOX are degraded by 99.5% (0.042 min-1), 83% (0.016 min-1), 72% (0.011 min-1) and 95% (0.026 min-1) of its initial concentration respectively. Photocurrent density of 20N-KBFO improves to 8.83 mA/cm2 from 4.31 mA/cm2 for pure KBFO. Photocatalytic and photoelectrochemical (PEC) properties of N-doped KBFO make it a promising candidate for energy and environmental applications. [ABSTRACT FROM AUTHOR]

A novel UV–visible light active oxynitride photocatalyst, ZnO:InN, has been demostrated to exhibit efficient hydrogen evolution from water as compared to some conventional photocatalysts. A reduction in bandgap (2.82 eV), as estimated from diffuse reflectance spectra, is explained using Valence band XPS studies and attributed to the upshift in valence band maximum. Photocatalytic activity of the samples has been demonstrated by organic dye degradation, where 92% decay was observed in 180 min under direct sunlight. Photoelectrochemical studies under visible light showed significant photoresponse with a photocurrent density of ∼8 μA/cm2. This study, as per our knowledge, is first of its kind where ZnO:InN oxynitride has been explored as a UV–visible light active photocatalyst with significant H 2 generation of ∼48 μmol/g by UV–visible light water splitting using methanol scavenger. The results show the promising future applications of ZnO:InN oxynitride as a sunlight active photocatalyst for hydrogen production. • Synthesis of novel Zn 1-x In x O 1-y N y oxynitride photocatalyst for H 2 evolution. • Bandgap modification to 2.82 eV. • Methylene blue degradation upto 92% under direct sunlight. • Significant Photocurrent generation under UV–Vis irradiation. • Hydrogen evolution using Zn 1-x In x O 1-y N y oxynitride reported for first time. [ABSTRACT FROM AUTHOR]

Abstract Zn 1-x Ga x O 1-y N y oxynitride has gained immense importance in the field of photocatalytic hydrogen generation and organic dye degradation; especially due to its narrow band gap, making it active under visible spectra. In the present work, the activity of Zn 1-x Ga x O 1-y N y oxynitride photocatalyst has been enhanced significantly when a composite of graphene oxide with Zn 1-x Ga x O 1-y N y is designed. Graphene oxide is synthesized via oxidative treatment of graphite by modified Hummers method while Zn 1-x Ga x O 1-y N y sample is synthesized via solution combustion technique. The integration of graphene oxide with the solid solution was carried out via two different techniques namely solution combustion and sonication route. The ability of the compound to generate charge carriers and produce photocurrent was explored using Photoelectrochemical measurements. Photocatalytic activity was evaluated by the degradation of organic dye under sunlight. Highlights • Two different simple methods for synthesis of nanocomposites between Zn 1-x Ga x O 1-y N y and Graphene Oxide. • Photocatalytic dye degradation under natural sunlight and Photoelectrochemical measurements under visible light radiation. • Integration with Graphene oxide results in better photocatalytic activity. [ABSTRACT FROM AUTHOR]

The recognition of photocatalysis as a promising approach for green energy generation and environmental pollution degradation has resulted in the emergence of a large number of semiconductor materials as photocatalyst. Here we introduce a non-oxide compound, Zn 1-x-y Ga x Co y O 1-z N z oxynitride synthesized by solution combustion technique for application as visible light photocatalyst. The structural, microstructural, spectroscopic and photoelectrochemical studies of the samples are demonstrated. The wurtzite structured sample possessed bandgap of 2.76 eV allowing absorption in visible region of spectra which is explained using Valence Band XPS studies. The photoelectrochemical studies on the samples revealed a photo-anodic behavior with total half-life of trap states significantly reduced compared to some conventional photocatalyst materials. [ABSTRACT FROM AUTHOR]

Here we report the synthesis of graphitic carbon nitride (g-C 3 N 4)/brownmillerite KBiFe 2 O 5 (KBFO) based heterojunction photocatalyst. The heterojunction composite revealed rod shaped KBFO embedded on the surface of g-C 3 N 4. The distinct phases of individual compounds are revealed through X-ray diffraction. An effective reduction in bandgap energy of KBFO/g-C 3 N 4 (KCN) composite in comparison to pristine g-C 3 N 4 confirmed the formation of heterojunction. Photocatalytic performance of as developed heterostructures is tested and compared by degrading common organic effluent methylene blue (MB). 25 wt% of g-C 3 N 4 content in KBFO sample shows a remarkable improvement (92% degradation efficiency) over pure KBFO (77%) and g-C 3 N 4 (54%). The electrode composed of 25 wt% g-C 3 N 4 content in KBFO also reveals significant photoelectrochemical response (0.3 mA/cm2) over KBFO (1.5 μA/cm2). The improvement was attributed to an effective electron-hole separation in the heterojunction. These stable and reusable KBFO/g–C 3 N 4 heterostructures hold promising future materials for energy and environmental applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel one-pot ultrarapid sonochemical synthesis technique is demonstrated. • Multi-component ZnO-Cu x -GO y hierarchical structures are fabricated. • Bandgap energy of ZnO-Cu 1.0 -GO 0.25 HSs decreased to 2.90 eV. • Ibuprofen was efficiently degraded using ZnO-Cu 1.0 -GO 0.25 HSs under visible light. • Synergistic effect of Cu doping and GO addition enhanced photocatalytic efficiency. Three-dimensional (3D) hierarchical structures (HSs) have demonstrated excellent properties for various applications that are attributable to their distinctive micro-sized architecture with nanoscale substructures. Recently, the ultrarapid sonochemical approach was found to be an effective strategy for synthesizing single component HSs with uniform morphologies in comparison to the direct precipitation technique. We here report the fabrication of copper doped zinc oxide grafted on graphene layers (ZnO-Cu x -GO y) for exploring the capability of this ultrarapid approach for synthesizing multi-component HSs. Interestingly, the morphology of ZnO-Cu x -GO y HSs studied through electron microscopy revealed the growth of ZnO HSs decorated with Cu nanoparticles and interconnected by graphene layers. ZnO-Cu x -GO y HSs demonstrated three-fold higher efficiency in the photodegradation of ibuprofen (IBU) under visible light irradiation in comparison to pristine ZnO HSs, which is attributable to the combined influence of the doped Cu2+ ions and graphene, enabling improved visible light absorption and inhibiting the recombination of photogenerated charges. Thus, the novel ultrarapid sonochemical synthesis strategy demonstrated here is anticipated to open up a new horizon for the time-saving and scalable design of multi-component HSs of various materials for a myriad of applications. [ABSTRACT FROM AUTHOR]