Reduction In Band Gap Energy Research Articles

Twisted Benzothieno-Fused BOPHY Dyes as Triplet Photosensitizers with Long-Lived Triplet Excited States.

The synthesis of a series of photostable [b]-benzothieno-fused BOPHY derivatives is reported via one-pot condensation of formylated isoindoles or formylindoles with hydrazine and subsequent boron complexation. These dyes show strong absorption in the deep red region and acceptable fluorescence quantum yields (∼30%). The two fused benzothiophene moieties are slightly deviated from the BOPHY core (with dihedral angles of 6.1 and 10.2°). This slightly twisted conformation brings an enhanced spin-orbit coupling and a reduced energy band gap between singlet and triplet states. The enhanced intersystem cross process endows these series of dyes with a good singlet oxygen quantum yield (up to 63%), a high triplet-state quantum yield (up to 78%), and a long lifetime value (up to 127 μs). Density functional theory calculations indicate that the transition from S1 to T2 states is crucial for triplet-state formation, highlighting their high efficiency in intersystem crossing. The calculated triplet electron spin surface reveals a widespread distribution of triplet states across the conjugated molecular structure, which enhances the Dexter mechanism for triplet energy transfer in these BOPHY photosensitizers. These findings are helpful for thorough understanding of the fundamental ISC process and developing triplet photosensitizers.

Influence of annealing temperature on Fe₂O₃ nanoparticles: Synthesis optimization and structural, optical, morphological, and magnetic properties characterization for advanced technological applications

In this study, Iron oxide nanoparticles (Fe₂O₃ NPs) were synthesized using iron chloride hexahydrate (FeCl3·6H2O) and ammonia solution through a straightforward co-precipitation method. The nanoparticles were annealed at temperatures of 100 °C, 300 °C, 500 °C, 700 °C, and 900 °C, with one sample left unannealed. Comprehensive analyses were performed using X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Zeta potential, Dynamic Light Scattering (DLS), Scanning Electron Microscopy (SEM), and UV–Vis Spectrophotometry. The XRD patterns confirmed the presence of both Maghemite (γ-Fe2O3) and Hematite (α-Fe2O3) phases, with a phase transition observed between 100 °C and 300 °C, and the most pronounced transition occurring at 500 °C. At this optimal temperature, the crystallite size was 19.14 nm, the average particle size was 37.36 nm, and the band gap energy was measured at 1.76 eV. SEM images revealed that nanoparticles formed clusters as the annealing temperature increased. The zeta potential measurements showed a range from 6.12 mV at 100 °C to −1.9 mV at 900 °C, indicating changes in particle stability. DLS analysis indicated a size increase from 86.81 nm at 300 °C to 1577 nm at 900 °C, reflecting aggregation trends. The reduction in band gap energy with higher temperatures is attributed to enhanced crystallinity and increased particle size. The magnetic properties of Fe₂O₃ NPs were evaluated using a Physical Property Measurement System (PPMS), revealing an increase in magnetic response with rising annealing temperatures. The transition from superparamagnetic γ-Fe₂O₃ to weakly ferromagnetic α-Fe₂O₃ was confirmed through changes in the hysteresis loop area and shape. These findings suggest that 500 °C is the optimal annealing temperature for producing Fe₂O₃ NPs with desirable properties for applications in targeted drug delivery, MRI contrast enhancement, and environmental remediation. This research advances the engineering of Fe₂O₃ NPs, paving the way for their use in various technological applications.

Modification of MWCNTs with Bi2WO6 nanoparticles targeting IL-1β and NLRP3 inflammasome via augmented autophagy.

This study reports the facile hydrothermal synthesis of pure Bi2WO6 and Bi2WO6\MWCNTs nanocomposite at specific molar ratio 1:2.5 of Bi2WO6:MWCNTs and elucidates their role in modulating the NLRP3 inflammasome pathway via autophagy induction. Comprehensive characterization techniques, including XRD, Raman, UV.Vis PL,FESEM,EDS and TEM, revealed the successful incorporation of MWCNTs into the Bi2WO6 structures, leading to enhanced crystattlinity, reduced band gap energy (2.4 eV) suppressed charge carrier recombination and mitigated nanoparticles aggregation. Notably, the reduced band gap facikitaed improved visible light harvesting, a crucial attribute for photocatalytic applications. Significantly, the nanocompsoite exhibited a remarkable capacity to augment autophagy in bone marrow-derived macrophages (BMDMs), consequently down-regulating the NLRP3 inflammasom activation and IL-1β secretion upon LPS and ATP stimulation. Immunofluorescence assays unveiled increased co-localization of LC3 and NLRP3, suggestion enhanced targeting of NLRP3 by autophagy. Inhibition of autophagy by 3-MA reversed these effects, confirming the pivotal role of autophagy induction. Furthermore, the nanocomposite attenuated caspase-1 activation and ASC oligomerzation, thereby impeding inflammasome assembly. Collectively, these findings underscore the potential of Bi2WO6\MWCNTs nanocompsite as a multifaceted therapeutic platform, levering its tailored optoelectronic properties and sbility to modulate the NLRP3 infalmmasome via autophagy augmentation. This work covers the way for the development of advanced nanomaterials with tunable functionalities for combating inflammatory disorders and antimicrobial applications.

The Effect of Heat Treatment on the Sol–Gel Preparation of TiO2/ZnO Catalysts and Their Testing in the Photodegradation of Tartrazine

This study aims to synthesize TiO2/ZnO powders and to study the effect of heat treatment on their photocatalytic ability against the Tartrazine anionic dye. The as-obtained powders with the following compositions—90TiO2/10ZnO and 10TiO2/90ZnO (mol%)—were obtained by the sol–gel technique. The prepared gels were annealed at 500 °C and 700 °C and subsequently characterized by XRD, UV–Vis, and SEM methods. The single crystalline phase of TiO2, which has been detected at up to 500 °C is anatase, while for ZnO, it is the hexagonal wurtzite structure. Further increases in the temperature (700 °C) led to the appearance of rutile in the samples. The SEM analysis demonstrated that the binary oxide materials had irregular shaped particles with a tendency to agglomerate. The UV–Vis spectra of the gels exhibited a red shift in the cut-off of the 90TiO2/10ZnO sample compared with pure Ti(IV) butoxide. Photocatalytic tests showed that the investigated samples possessed photocatalytic activity toward Tartrazine. Compared with TiO2, the prepared TiO2/ZnO photocatalysts showed superior properties in the photodegradation of a Tartrazine water solution. The target photocatalysts’ enhanced photocatalytic activities can be explained by their reduced band gap energy, improved surface physicochemical characteristics, separation of photo-induced electron–hole pairs, and lowered recombination rate. Higher photocatalytic activity was observed for powders annealed at 500 °C, with the 10TiO2/90ZnO (mol%) sample exhibiting the highest photocatalytic degradation of the used organic dye.

Z-scheme driven charge transfer in g-C3N4/α-Fe2O3 nanocomposites enabling photocatalytic degradation of crystal violet and chromium reduction

In this study, we demonstrated the design and fabrication of iron oxide-embedded protonated graphitic carbon nitride (α-Fe2O3/p-g-C3N4) nanocomposites for photocatalytic dye degradation and heavy metal reduction applications under sunlight irradiation. The developed nanocomposites, with varying weight percentages of α-Fe2O3, were characterized for their structural (XRD, FTIR, XPS), optical (absorption and photoluminescence), morphological (FE-SEM, TEM), and electrochemical (EIS) properties to elucidate their structure-property relationships. The synthesis method ensures the uniform dispersion of α-Fe2O3 nanoparticles, with a particle size range of 50–60 nm, onto p-g-C3N4. XPS analysis suggests the formation of an electrical layer at the interface of α-Fe2O3/p-g-C3N4, facilitating the formation of a Z-scheme heterojunction. The photoluminescence and EIS spectra of the nanocomposite indicated effective separation and transfer of photo-induced charge carriers, aided by a reduced bandgap energy of ∼2.63 eV. Notably, the optimized 10 wt% α-Fe2O3/p-g-C3N4 nanocomposite exhibited superior photocatalytic activity, degrading nearly 100 % of crystal violate dye and reducing 98 % of Cr(VI) ions, compared to bare p-g-C3N4, which degraded around 43 % of the dye and reduced 39 % of Cr(VI) ions under sunlight irradiation. Scavenger studies indicated that α-Fe2O3/p-g-C3N4 nanocomposites produce adequate superoxide anions and hydroxyl radicals for dye degradation and heavy metal ion reduction. The composite also demonstrated consistent recyclability up to 5 cycles with around 100 % cyclical efficiency. The pH-dependent photoreduction and cyclic dye degradation by the 10 wt% α-Fe2O3/p-g-C3N4 photocatalyst indicated excellent stability, making it suitable for the treatment of multi-pollutant wastewater.

Blue Na2O - CoO - P2O5 glasses: Structural, physico-chemical, thermal and optical characterizations

Two blue phosphate glasses series, (50-x/2)Na2O - xCoO - (50-x/2)P2O5 (0 ≤ x ≤ 35) and (50-x)Na2O - xCoO - 50P2O5 (0 ≤ x ≤ 50) labelled NaCoPO(I) and NaCoPO(II), were synthesized by the melt quenching route and characterized by diverse techniques. Introduction of cobalt oxide CoO in vitreous NaPO3 metaphosphate induces an increase in the glass transition temperature, a decrease in the molar volume and the dissolution rate of the glasses in distilled water, and therefore a strengthening of the glass network. Raman spectra of NaCoPO(I) series, where O/P ratio varies from 3 to 3.54, show that Co2+ ions breakdown the infinite metaphosphate chains and provoke remarkable structural modifications. In contrast, no significant change was observed in the glassy network of NaCoPO(II) series, where O/P ratio is constant and equal to 3. Optical study results show that Co2+ ions have both octahedral and tetrahedral environments with predominance of tetrahedral coordination. The reduction in band gap energy when CoO content rises is due to the increase of non-bridging oxygen number in the vitreous network. The values of CIE L∗a∗b∗ parameters are consistent with the blue color, sought for commercial pigments. The physical parameters deduced from optical spectra suggest that the studied glasses are promising materials for several applications such as pigments and nonlinear optical materials.

Controlled synthesis of 3D pseudocubic Fe2O3/BiFeO3 heterojunction photocatalyst for effective ciprofloxacin-HCl and methyl orange degradation

Nano-particle-based Iron (III) oxide (Fe2O3) and nanosheet-based bismuth ferrite (BiFeO3) photocatalysts were successfully prepared through a solid-state thermal decomposition approach. Especially, loading BiFeO3 over Fe2O3 demonstrated a 3D pseudocubic-based hierarchical architecture of Fe2O3/BiFeO3 (FeBiOx), which exhibits enhanced photodegradation efficiency of about 98.3 % for antibiotic ciprofloxacin-HCl (C-HCl) and 97.8 % for pollutant methyl orange (MO) under ultraviolet (UV) light irradiation within 180 and 150 min, respectively, compared to pure BiFeO3 and Fe2O3. The improved photocatalytic performance of FeBiOx was ascribed to the increased surface area, Type-II charge transfer scheme, effective charge migration efficiency induced by the surface plasmon resonance (SPR) effect of metal-Bi, and reduced bandgap energy.

Photocatalytic reduction of nitroarene derivatives by impressive visible-light active Co3O4-QDs/Mn3O4 nanocomposite

A visible light active Co3O4-quantum dots (QDs)/Mn3O4 nanocomposite was successfully synthesized by a straightforward precipitation approach. Notably, the formation of Mn3O4 nanosheets in composite structure was evidenced by different physicochemical techniques especially transmission electron microscopy (TEM), energy dispersive X-ray (EDX) and N2 sorption analyses, which indicated the uniform distribution of Co3O4-QDs with small size of around 5 nm on the surface of Mn3O4 nanosheets along with the enhancement of specific surface area for final composite. Also, the persistence of Co3O4-QDs during nanocomposite synthesis was analyzed by X-ray diffraction (XRD), FT-IR and TEM techniques. The diffuse reflectance UV–Vis and electrochemical impedance spectroscopies revealed the reduction of band gap energy and enhanced charge separation efficiency for Co3O4-QDs/Mn3O4 nanocomposite, respectively, which consequently led to improved photocatalytic response in comparison with bare Co3O4-QDs and Mn3O4 nanosheets. The as-prepared nanocomposite exhibited excellent photocatalytic activity in the reduction of a wide range of substituted nitroarenes with the yields of higher than 80 % relative to the corresponding arylamines, using N2H4·H2O as the hydrogen source and ethanol as green solvent at 25 °C and ambient pressure under visible light illumination. The synergistic effect could improve the production of active hydrogen atoms, therefore, the reasons for this transformation over the prepared nanocomposite under benign conditions are fully discussed. Furthermore, the nanocomposite could be easily recycled without decay in photocatalytic activity for at least five successive cycles.

Hybrid magnetic nanocomposite NiFe2O4/TiO2 for Photocatalytic dye degradation and green hydrogen (H2) generation

The present paper focuses on designing and developing nanocomposites to modify their properties to increase the ability to generate hydrogen and degrade photocatalytic dyes. A nanocomposite of nickel ferrite (NiFe2O4)/Titanium dioxide (TiO2) was formulated using the sol-gel self-ignition method. X-ray diffraction (XRD) tool was adopted to analyze the structural behavior of pure nickel ferrite (NiFe2O4), pure titanium dioxide (TiO2), and nanocomposite of NiFe2O4/TiO2. XRD pattern of NiFe2O4 and TiO2 shows a monophasic nature whereas the XRD pattern of nanocomposites shows mixed phases of NiFe2O4 and TiO2. FTIR spectra confirm the formation of NiFe2O4, TiO2, and their composites with absorption bands near 400 cm-1 and 600 cm-1, 1500 cm-1. Raman spectra unveiled the presence of five active Raman modes in the case of NiFe2O4 whereas three active Raman modes are seen in TiO2. Field emission scanning electron microscopy (FE-SEM) images exposed the dense structure with spherical cluster-like morphology in the case of NiFe2O4. Energy-dispersive X-ray spectroscopy (EDX) analysis confirms the presence of all the desired elements of NiFe2O4, TiO2, and their composites in stoichiometric proportions. BET analysis of nickel ferrite NPs suggests a large surface area of the order of 31.54 m2/gm in comparison with TiO2 (19.23 m2/gm). The optical characterization was made through the UV-visible spectroscopic technique. TiO2 shows a maximum band gap of the order of 3.02 eV while NiFe2O4 shows a low band gap of the order of 1.74 eV. A typical M-H curve with saturation magnetization of the order of 27.54 emu/gm was observed for pure NiFe2O4. No magnetic properties were observed for TiO2 as it is a semiconductor. Enhancement in magnetic properties is observed with increases in NiFe2O4 content in a composite of NiFe2O4/TiO2. The photocatalytic activities were examined by degrading Methylene Blue (MB) dye under sunlight for pure nickel ferrite (NiFe2O4), pure titanium dioxide (TiO2), and a nanocomposite of NiFe2O4/TiO2. Photocatalytic hydrogen production reactions were carried out in a methanol/water solution under visible light. Consequently, the best configuration of the photocatalyst was determined as 25% wt% NiFe2O4/ TiO2 which had shown the maximum hydrogen (H2) production rate as 146.3 μmol/g/h after 8 h owing to its reduced bandgap energy and delayed e- / h+ recombination.

Dye degradation and antimicrobial efficacy of cesium-doped Y2O3 nanostructures: in silico docking study.

Developing multifunctional nanomaterials is crucial to rising global concerns over environmental contamination caused by dye effluents and antibiotic resistance. This work presents cesium (Cs)-doped Y2O3 nanostructures (NSs) as viable options for catalytic dye degradation and antibacterial action. This study prepared yttrium oxide (Y2O3) and various (2, 4, and 6 wt%) concentrations of Cs-doped Y2O3 NSs via co-precipitation technique. The pure and Cs-doped Y2O3 NSs were used to degrade methylene blue (MB) at different pH levels and assess the antibacterial properties against multidrug-resistant (MDR) Escherichia coli (E. coli). The X-ray diffraction spectra of the pure and Cs-doped Y2O3 revealed the presence of cubic and monoclinic structures. The UV-vis absorption spectra displayed distinct peaks at 274 nm and a reduction in band gap energy (from 4.94 eV to 4.41 eV) upon incorporation of Cs. Maximum degradation efficiency of up to 99% attributed to 6% Cs-doped Y2O3. The bactericidal activity against MDR E. coli exhibited 4.15 mm inhibition zones at higher concentrations of Cs-doped Y2O3. The bactericidal mechanism of Cs-Y2O3 NSs was further investigated by molecular docking studies for β-lactamase and DNA gyrase enzymes.

Influence of Pd, Pt and Au nanoparticles in the photocatalytic performance of N-TiO2 support under visible light.

In this article, we report the modification and photocatalytic evaluation of commercial TiO2-P25 under visible light for methyl orange (MO) dye degradation under visible light. The activity of materials doped with N, Pd, Pt and Au on to the TiO2-P25 was evaluated, with optimal photocatalytic performance achieved using Au nanoparticles doped on an N-functionalized titania surface. X-ray diffraction (XRD), physical nitrogen adsorption/desorption isotherm curves, transmission electron microscopy (TEM), diffuse reflectance spectroscopy, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) were used to study the structural and textural properties of the samples. The chemical species present in the bulk and surface of the catalysts were identified using X-ray photoelectron spectroscopy (XPS) and microwave plasma-atomic emission spectroscopy. The results show that Au/N-TiO2 photocatalyst presents a remarkable enhanced activity for MO dye degradation, under visible light illumination, reaching 100% after 4 h. The enhanced photocatalytic activity using this composite is attributable to the well-dispersed and small size of Au nanoparticles, large surface area, reduction of band-gap energy and the interaction between nitrogen and Au which promoted a synergistic effect. This article is part of the discussion meeting issue 'Green carbon for the chemical industry of the future'.

Rationalizing Defective Biomimetic Ceria: In Vitro Demonstration of a Potential “Trojan Horse” Nanozyme Based‐Platform Leveraging Photo‐Redox Activities for Minimally Invasive Therapy

AbstractSemiconductor nanostructures with surface defect‐mediated chemistry have garnered pronounced interest due to their exceptional photo‐induced intracellular bio‐catalytic (enzyme‐mimicking) responses. However, designing defective nanozymes with pH‐responsive multi‐bio‐catalytic functions without any dopants is challenging. Herein, oxygen‐deficient “trojan horse‐like” folate‐functionalized, L‐arginine‐coated ceria (FA‐L‐arg‐CeO2) nanozymes with synergistic multi‐enzyme‐mimicking and anti‐cancer potential are introduced. Intrinsic surface oxygen vacancies (VO●) are strategically created in the nanozymes under kinetically favorable synthesis conditions. Increased surface VO● promotes band structure reconstruction and amplified photochemical‐response efficacy under single laser irradiation (808 nm), outperforming the defect‐free commercial nano‐CeO2 in rapid anti‐tumorigenic activities. Through folate receptor‐mediated endocytosis, these biostable nanozymes localized in MDA‐MB‐231 cells (84% in 48 h) and demonstrated NIR‐accelerated enzymatic functions depending on the pH of the biological milieu. The reduced band gap energy facilitated effective electron‐hole separation, up‐regulating in vitro photo‐redox reactions that impart exceptional therapeutic potential and inhibit 62% cell metastasis within only 12 h. By perturbing intratumoural redox homeostasis, VO●‐rich FA‐L‐arg‐CeO2 nanozymes unanimously killed 86% of MDA‐MB‐231 cancer cells while preferentially shielding benign L929 cells. Transcending beyond conventional drug‐loaded or dopant‐incorporated‐CeO2 nanoplatforms, these defective multi‐modal nanozymes unravel a new avenue for developing smart, low‐cost, bio‐active agents with enhanced efficacy and bio‐safety.

Pressure-dependent optoelectronic properties of TlInS2 crystals (II): Insights from DFT simulations

This study investigates the structural and optical properties of TlInS2 crystals under elevated pressures using density functional theory (DFT). The dielectric function shows significant shifts under pressure, indicating changes in electronic transitions and band structures. Analysis of the refractive index reveals pressure-induced spectral peaks and a semiconductor-to-metal transition at 6.25 GPa. Reflectivity measurements show an increase with pressure, reaching 0.504 at 10 GPa, suggesting enhanced optical properties. Optical conductivity analysis shows increased total conductivity with pressure due to reduced band gap energy, stimulating exciton formation and metallic behavior beyond 6.25 GPa. These comprehensive insights into the pressure-dependent behaviors of TlInS2 are essential for potential applications in electronic and optoelectronic devices.

Promising CO2 gas sensor application of zinc oxide nanomaterials fabricated via HVPG technique

Highly effective gas sensors for detecting a range of hazardous and toxic gases were successfully applied in the present study using Zinc oxide (ZnO) nanomaterials. In this work, the horizontal vapor phase growth (HVPG) technique was perfectly capable of the synthesis of zinc oxide (ZnO) nanomaterials. The effect of the growth time with different dwell times was discussed by comparing the SEM-EDX analysis and photoluminescence characterization of the samples. Magnetic field (AMF) was also incorporated to determine the effect of AMF on the synthesis of ZnO nanomaterials. The results showed that the ZnO nanorods and root-like shapes are formed with more than 5 μm length and a few nm diameters. The optimum parameter showed the sensors are shiner than the less effective sensor when applied. The introduction of an external magnetic field led to a reduced energy band gap by a maximum of 15 %. The non-AMF band gap energy value is observed to be between 3.51 and 3.58 eV, while the value obtained using AMF is found to be between 2.94 and 3.22 eV. During the CO2 gas sensor test, AMF ZnO nanomaterial samples exhibited higher voltage and gradient compared to non-AMF samples.

Ni-Pt nanoparticle decorated, C, N-doped titania microparticles with low band gap energy as an efficient catalyst for hydrogen generation from hydrous hydrazine

The recent studies demonstrated superior catalytic activity and higher selectivity of carbon doped defect-rich catalysts in hydrogen production via dehydrogenation of hydrazine hydrate (HH). The synthesis of a new defect-rich catalyst capable of providing high hydrogen evolution rate in either catalytic or photocatalytic dehydrogenation of HH was aimed. For this purpose, “polymerization-induced colloid aggregation” (PICA) was proposed for the synthesis of carbon and nitrogen doped-mesoporous, gravel-like TiO2 microparticles (m-CN/TiO2 MPs) with a reduced band-gap energy of 2.3 eV. The Ti(III) content and oxygen vacancy concentration of pristine m-CN/TiO2 MPs were 6.06 % and 22.57 %, respectively. A defect-rich catalyst with high Ti(III) content (40.25 %) and high oxygen vacancy concentration (39.14 %) was obtained by the decoration of m-CN/TiO2 MPs with nickel-platinum nanoparticles (Ni-Pt NPs) via NaBH4 reduction (Ni-Pt/m-CN/TiO2 MPs) for the first time. The charge unbalance stimulated by Ti(III) species supported the formation of oxygen vacancies on m-CN/TiO2 MPs. The unique approach based on the synthesis of a C, N doped-mesoporous TiO2 based support by PICA and the deposition of Ni-Pt NPs by NaBH4 reduction in the presence of m-CN/TiO2 MPs allowed to obtain a heterogeneous catalyst with a low band energy of 1.7 eV for hydrogen production. The turnover frequency (TOF) values up to 1140.7 h−1 were achieved with 100 % H2 selectivity using the catalyst containing an active metallic site composed of 78.3 % mol Ni and 21.7 % mol Pt on m-CN/TiO2 MPs in the catalytic dehydrogenations performed at 323 K. The TOF values up to 530 h−1 with 100 % H2 selectivity were obtained by using Ni-Pt/m-CN/TiO2 MPs as a photocatalyst in the visible light driven photocatalytic dehydrogenation of HH at room temperature.

Probing the Photocatalytic Pathways of Iron (III) Protoporphyrin IX-Functionalized TiO2: A Study on Oxo-Iron(IV) Porphyrin π-Cation Radical Formation

The presence of phenolic compounds in aquatic environments, resulting from industrial activities such as coal processing and petroleum refining, poses significant concerns due to their adverse effects on water safety, even at minimal concentrations. These compounds present challenges during remediation using traditional techniques such as solvent extraction, biological treatments or chemical oxidations. In response to these challenges, Advanced Oxidation Processes have emerged as a promising solution, with methods like heterogeneous photocatalysis, ozonation, sonification and so on, showing potential for degrading persistent organic molecules[1] [2].Titanium dioxide (TiO2) has gained importance in environmental remediation due to its ease of synthesis, cost-effectiveness, and versatility. Its unique properties, including exceptional chemical stability and non-toxic nature, make it suitable for water purification among other applications. Several studies aim to extend responsiveness of TiO2 beyond UV-A radiation, seeking to harness the wider and more prevalent visible light spectrum. This endeavor is driven by the desire to optimize the utilization of solar energy in various applications. To enhance TiO2 absorption of visible light, alternative chromophores, particularly porphyrins, are employed. Porphyrins, known for their extended lifespan in the excited state and efficient photoabsorption in the visible region, serve as excellent sensitizers when combined with TiO2, enabling effective charge separation[3].This study explores the activity enhancement of TiO2 catalyst by incorporating iron (III) protoporphyrin IX (FePPIX). The objective is to understand how hydrogen peroxide (H2O2), generated through photocatalysis on the TiO2 surface, influences the formation of oxo-iron(IV) porphyrin π-cation radicals. These radicals specifically form through the interaction with iron porphyrin attached to TiO2, offering a unique pathway for efficiently degrading phenolic compounds, as is proposed in Figure 1. The investigation underscores the significance of TiO2 surface sensitization and the simultaneous emergence of porphyrin radicals in shaping the dynamics of the photocatalytic process.We fabricated TiO2 nanotube sheets (TiO2-NTs) by anodizing metallic titanium sheets and then functionalized them with FePPIX. The process involved degreasing, chemical cleaning, anodization, exfoliation, and thermal treatment for anatase phase formation. Additionally, we utilized anatase-TiO2 nanoparticles. We carried out functionalization, which included ozone exposure, UV-C light treatment, and immersion in an acidic FePPIX solution in methanol, reacting with the hydroxylated surface induced by ozone treatment. After functionalization, we carefully washed away the excess iron protoporphyrin with methanol, and we air-dried the materials at room temperature. We comprehensively characterized the nanomaterials using diverse analytical techniques, including Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR), Raman and UV-Vis spectroscopies, and ESR analyses. We further investigated the photogeneration of hydroxyl radicals (•OH) on FePPIX-functionalized and non-functionalized TiO2 nanotube arrays through the photobleaching of N-N-dimethyl-4-nitrosoaniline. Additionally, we studied phenol degradation under UV irradiation. Our findings provide detailed insights into the physical and chemical properties, morphology, and composition of the fabricated nanomaterials.The SEM images reveal well-defined nanotube arrays, underscoring the efficacy of the fabrication technique. Energy-Dispersive X-ray Spectroscopy mapping further solidifies this observation, confirming a uniform distribution of iron in functionalized nanoparticles and supporting the success of functionalization. FTIR and Raman spectroscopy provide detailed insights into the presence of functional groups and vibrational modes, establishing the success of the functionalization process as well. Tauc plots show a narrowed energy gap in functionalized nanotubes, hinting at their potential for visible light activity.Photocatalytic assessments uncover diminished behavior, with lower •OH generation rates observed under UV-A light for functionalized nanotubes but notable activity under visible light, aligning with the reduced band gap energy. Furthermore, enhanced phenol degradation on functionalized nanotubes under UV-A light, potentially associated with compound I, introduces complexity to the photocatalytic pathways. The application of ESR study confirms the presence of paramagnetic species, such as [PPFeIV=O]+•, thereby highlighting the influence of protoporphyrin on the TiO2 surface and its integral role in photocatalysis.In summary, the study confirms successful TiO2 nanomaterial functionalization with FePPIX, promising applications in environmental remediation. Analyses validate binding with hydroxyl groups, Tauc plots indicate enhanced photocatalytic activity under visible light, and ESR analysis suggests the presence of paramagnetic species that could improved phenol degradation. Further investigation is needed for a comprehensive understanding. Overall, these findings hold potential for efficient and sustainable wastewater treatment.[1] S. Rasalingam, R. Peng, R. T. Koodali, J. Nanomater. 2014, 617405.[2] Y. Deng, R. Zhao, Curr Pollut. Rep 2015, 1, 167.[3] C. C. Huang, P.S. Parasuraman, H. C. Tsai, J. J. Jhu, T. Imae, RSC Adv. 2014, 4, 6540. Figure 1

Tuning of structure, surface morphology and optical properties of spray-coated nickel tin oxide thin films by heat treatment

In this work, nickel tin oxide (NiSnO3) in a 1:1 ratio was synthesized using a simple spray pyrolysis technique followed by annealing at 450 °C for different time durations. The X-ray diffraction (XRD) revealed the polycrystalline nature with perovskite structure of NiSnO3 without the formation of any secondary phases. Annealing improved the crystallinity of the films. The annealed films exhibited a preference for orientation along the (310) plane. The largest crystallite size was obtained for 4 h of annealed film. The scanning electron microscopy (SEM) images of the films distinctly illustrate enhanced crystallinity following the annealing process. Energy-dispersive X-ray spectroscopy (EDS or EDX) indicates that the film possesses a near-stoichiometric composition. All the films resulted in more than 70 % transmittance in the visible region except for 8 h annealed. The gradual reduction of energy bandgap was observed for the sample. The four peaks at 358 nm, 415 nm, 436 nm, and 460 nm were observed in photoluminescence (PL) spectra corresponding to near band emission and defects related emissions respectively. The determined optical parameters from the present study indicate that the 4-h annealed film holds promise as a favourable option for optoelectronic and photonic devices.

“Yb modification of bismuth Ferrite: Unveiling Optical, Dielectric, and electrochemical properties for advanced applications”

This study explores the detailed impact of Yb3+ substitutional doping on the structural, optical, dielectric, and electrochemical characteristics of bismuth ferrite. Rigorous structural analysis conducted via X-ray diffraction confirmed the formation of a rhombohedral distorted perovskite structure, within the R3C space group. The investigation of crystallite size showed a reducing trend as Yb3+ content increased. Morphological studies revealed the presence of finely dispersed nanocrystalline grains, exhibiting particle size within the range from 281 to 197 nm. Raman spectroscopy unveiled notable phonon mode shifts towards higher wavenumbers, correlating with increased Yb3+ doping concentrations. Additionally, a discernible reduction in bandgap energy, from 2.15 to 1.98 eV, was observed with increasing doping levels. An improved dielectric response was observed with Yb3+ doping. Electrochemical assessments, employing cyclic voltammetry and galvanostatic charge–discharge techniques, revealed the superior electrochemical performance of the 30 % Yb-doped bismuth ferrite-modified electrode, demonstrating a specific capacitance of 575 Fg−1 at a scan rate of 10 mVs−1. These findings underscore the tailored engineering of Yb-doped bismuth ferrite nanoparticles, positioning them as promising candidates for the next generation of supercapacitor devices.

Efficient and selective cleavage of lignin C–C bonds under visible light facilitated by the Zn(II)-doped mesoporous graphitic carbon nitride photocatalyst

Despite the promise of photocatalysis for extracting aromatic compounds from renewable lignin feedstocks, the selective cleavage of Cα–Cβ bonds in lignin under mild conditions poses a persistent challenge, primarily due to their elevated dissociation energies and steric hindrance. Herein, an efficient photocatalytic strategy for selectively breaking the Cα–Cβ bonds of lignin with visible-light irradiation and room temperature is proposed, facilitated by the Zn(II)-doped porous graphitic carbon nitride (Zn/CN) photocatalyst. Reduced energy band gap and photoluminescence, along with intensified visible-light absorption and enhanced photocurrent of Zn/CN, contribute to its efficacy in photocatalytic activity. Consequently, the lignin model compound (2-phenoxy-1-phenylethanol) achieves a conversion rate of 99 %, demonstrating a notable selectivity of 97 % in specifically breaking the Cα–Cβ bonds. Mechanistic investigations identify that photogenerated holes play a pivotal role during the photocatalytic conversion. Additionally, the activity and selectivity of Zn/CN photocatalyst are further confirmed by the successful photocatalytic conversion of pine kraft lignin, yielding high-value chemicals such as benzoic acid and vanillin. This research proposes an economical, efficient, and facile method for utilizing renewable lignin feedstocks under photocatalysis, thus advancing the production of high-value aromatic compounds.

Synergistically improving the performance of spinel cathode for efficient oxygen reduction electrocatalyst

Optimizing the performance of ceramic fuel cells requires the creation of effective and inexpensive electrocatalysts for the oxygen reduction process. Here, we detail a plan for converting the inert spinel CoAl2O4 into a highly active and superior material for low-temperature ceramic fuel cells through Fe substitution. It turns out that the iron substitution aids in surface reconstruction, increasing oxidation-reduction reaction (ORR) activity. In addition, the reduction in energy bandgap due to Fe doping enhance the Cathode ORR performance, which may be triggered by the ions' kinetics at the surface and interface. The surface layer and Fe doping considerably aid the oxidation-reduction reaction, which creates more oxygen vacancies at the active oxygen site. The prepared materials exhibit enhanced fuel cell performance of 542 mW/cm2 at a temperature of 520 °C. Remarkably, the prepared cathode exhibits a commendable performance of 200 mW/cm2 at a temperature of 420 °C.Furthermore, the CoFe1Al1O4 cell exhibits a decreased Rp (polarization resistance) value of 0.6423 ohm-cm2 at a temperature of 520 °C, demonstrating rapid ORR kinetics. The distribution relaxation time (DRT) shows that the Cathode oxidation-reduction reaction (ORR) activity increased with Fe doping. We present a promising method for improving the oxidation-reduction reaction efficiency of low-temperature ceramic fuel cells.