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An amendment to this paper has been published and can be accessed via a link at the top of the paper. [ABSTRACT FROM AUTHOR]

Present work utilizes solar-driven photocatalysis as an eco-friendly, green technology to degrade organic contaminants in water. In situ synthesis of ZnS–ZnIn 2 S 4 composite was carried out with one pot facile hydrothermal route. The as prepared composite was characterized with X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Diffuse Reflectance Spectroscopy (DRS). The composite was found to have an effective optical bandgap of 2.82 eV explicating its activity in the visible region of solar spectrum. Photoactivity of the composite was utilized for degradation of organic contaminants (e.g. Methylene Blue, Ciprofloxacin) in water under UV, visible light and direct sunlight irradiation. The efficiency of the catalyst and kinetics of degradation are discussed in detail. The composite also shows an improved photocurrent density of 1.14 μA/cm2 and a photocatalytic degradation rate constant of 0.041 min−1. This work provides an insight to the development of a novel in situ composite with enhanced photocurrent generation and improved photocatalytic activity that can be utilized for environmental remediation applications. • One step in-situ ZnS-ZnIn 2 S 4 composite heterostructure formation. • ZnS-ZnIn 2 S 4 composite has red-shifted the activity of ZnS from UV region to visible region of the solar spectrum. • Photocatalytic application towards degradation of Methylene Blue and Ciprofloxacin under UV, Visible and direct sunlight. [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]

Photocatalysis requires light absorption as well as efficient extraction of the photogenerated electron–hole pairs to chemically active sites. To avoid electron–hole recombination, we need tailored nanostructures which can demonstrate novel light absorption and thermodynamic properties. This work shows that band gap modification/narrowing due to the formation of solid solution along with an increased surface area of the nanostructures are ideal for solar harvesting and is a self sufficient photocatalytic agent even in absence of a co-catalyst. The present study suggests that the rate of H 2 production for GaN was negligible and it increased to 32.43 μmol/g/h for the solid solution under visible light irradiation (>400 nm) even in the absence of a co-catalyst. The apparent quantum yield (AQY) efficiency of H 2 evolution was found to be 0.8%. This highly desirable increased H 2 generation activity is attributed to the additional linewidth broadening in the photoluminescence spectra of nanostructured wurtzite Ga 1−x Zn x O 1−z N z solid-solution due to Ga/Zn and N/O interdiffusion giving rise to a modified bandgap and N2p-O2p interaction in the lattice. These inferences are also corroborated by diffuse reflectance spectra of the samples. For the first time, origin of hitherto unreported weak features appearing in the low energy Raman spectrum is also discussed. A series of characterization tools including structural, microstructural, optical, spectroscopic and Photocatalytic hydrogen production studies were employed to support our claim. [ABSTRACT FROM AUTHOR]

Brownmillerite KBiFe 2 O 5 (KBFO) absorbs large part of the solar spectrum due to its smaller bandgap. This optical response has immense potential in photocatalytic applications. In this work, KBFO was successfully synthesized using citrate combustion method. X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS) as well as Mössbauer spectroscopic studies, identify the valence state of Iron (Fe) as Fe3+. The strong magneto-dielectric coupling in KBFO was demonstrated by integrating both magnetization (M) and dielectric constant (ε) characteristics as a function of temperature. Magnetic and dielectric transitions were observed in close proximity in temperature range ∼780 K–760 K respectively. To the best of our knowledge, the photoelectrochemical properties of as developed KBFO were analyzed for the first time revealing a significant photoresponse with an average photocurrent density of 0.1 μA cm−2. The photocatalytic properties of KBFO were investigated by degrading organic effluent methylene blue (MB) under direct sunlight followed by a comparison with the photodegradation performance of perovskite BiFeO 3 (BFO). KBFO showed enhanced photocatalytic performance as compared to BFO due to its enhanced structural and optical properties. Image 1 • Multifunctional brownmillerite KBiFe 2 O 5 developed using citrate combustion method. • Strong magneto-dielectric coupling in KBiFe 2 O 5. • Photoelectrochemical properties of KBiFe 2 O 5 analyzed for first time and average current density found to be ∼0.1 μA/cm2 • Enhanced photodegradation efficiency of KBiFe 2 O 5 (E g = 1.67eV), over regular perovskite BiFeO 3 (Eg = 2.1 eV). [ABSTRACT FROM AUTHOR]