UV Vis Diffuse Reflectance Spectroscopy Research Articles

Synergistic Effects of Multiple Heterojunctions and Dopant Atom for Enhancing the Photocatalytic Activity of C-Modified Zn-Doped TiO2 Nanofiber Film

To design efficient photocatalytic systems, it is necessary to inhibit the compounding of electron-hole pairs and promote light absorption in photocatalysts. In this paper, semiconductor heterojunction systems of C-modified Zn-doped TiO2 composite nanomaterials with nanofiber structures were synthesized by electrospinning and hydrothermal methods. The composite nanofiber film was thoroughly characterized and the morphology, structure, chemical phases and optical properties were determined. Scanning electron microscopy confirmed that the nanofiber diameter was 150–200 nm and the C particles were uniformly modified on the smooth nanofiber surfaces. X–ray diffraction patterns and Raman show TiO2 as a typical anatase, modified C as graphite and Zn as ZnOcrystals. Moreover, the entry of Zn and C into the TiO2 lattice increases the crystal defects. Meanwhile, TiO2, ZnO and graphite form multiple heterojunctions, providing pathways for photogenerated carrier transfer. These synergistic effects inhibit the recombination of electron-hole pairs and provide more reaction sites, thus improving the photocatalytic efficiency. UV-Vis diffuse reflectance spectroscopy and fluorescence spectroscopyimply that these synergistic effects lead to improved optical properties of the composite. Using organic dyes (methylene blue, methyl orange, rhodamine Bandmalachite green) as simulated pollutants, the composite nanofiber film exhibited good photocatalytic activity for all dyes due to the significantly large specific surface area, small size effect and synergistic effects of multiple heterojunctions and dopant atom. In addition, the nanofiber film has good reusability and stability for the photodegradation of organic dyes, so it has potential for industrial applications.

Constructing Z-Scheme 0D/2D TiO2 Nanoparticles/Bi2O3 Nanosheet Heterojunctions with Enhanced Visible Light Induced Photocatalytic Antibiotics Degradation and Hydrogen Evolution

Photocatalysis has been regarded as a promising technology for degrading organic pollutants in wastewater and producing hydrogen. In this paper, TiO2 nanoparticles (NPs) were synthesized to improve the visible light absorption of TiO2, which were further combined with Bi2O3 nanosheets to synthesize a series of 0D/2D TiO2 NPs/Bi2O3 nanosheet heterojunctions. The visible light induced photocatalytic activities of the as-synthesized TiO2/Bi2O3 heterojunctions were studied. The optimized catalyst TB-3 with 15 wt% of Bi2O3/TiO2 exhibited the best photocatalytic degradation of tetracycline hydrochloride (TC). The degradation rate constant k of TC over TB-3 was approximately eight times and 39 times greater than that of P25 and Bi2O3, respectively. Additionally, TB-3 showed the highest amount of hydrogen evolution, while that of Bi2O3 was almost zero. The enhancement of photocatalytic performances was ascribed to the improved visible light absorption and the Z-scheme charge transfer path of the TiO2/Bi2O3 heterojunctions, which enhanced the separation efficiency and reduced recombination of photogenerated charge carries, as evidenced by UV–Visible diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL), and electrochemistry measurements. The active species trapping experiments and the electron spin resonance (ESR) results revealed that ·O2− was the main active substance in the photocatalytic degradation. The possible degradation pathway and intermediate products of TC have been proposed. This work provides experimental evidence supporting the construction of Z-scheme heterojunctions to achieve excellent visible light induced photocatalytic activity.

The exceptional performance of the plasmonic Au-Fe/TiO2 nanocatalysts achieved by O2 plasma activation

The plasmonic Au-based bimetallic nanocatalysts have the potential to exhibit superior visible-light (VL) photocatalytic activity, and their performance in reaction is greatly dependent on the method of activation. Herein, Au-Fe/TiO2 nanocatalysts are prepared by a modified incipient wetness impregnation method with the precursors of HAuCl4 and FeCl3. The visible-light activities of the samples activated by calcination at 300 °C, 50%H2/Ar plasma and O2 plasma are compared using CO oxidation. Au-Fe/TiO2 activated by O2 plasma has the most exceptional performance with a CO conversion of 90%. The samples are characterized by transmission electron microscopy, UV–vis diffuse reflectance spectroscopy, X-ray photoelectron spectra, and CO chemisorption. It is found that O2 plasma restructures nano Au and Fe on the TiO2 support into Au-Fe alloy, preventing nano Au particle size increase. The Au-Fe alloy nanoparticles on TiO2 has a narrow size distribution and are approximately 4 nm in size. Many surface oxygen species on Au-Fe alloy are observed, as well as a unique board peak assigned to CO adsorption, and they can improve the activity and stability of Au-Fe alloy in CO oxidation. Finally, a reaction mechanism of Au-Fe/TiO2 activated by O2 plasma for CO oxidation is developed. This research demonstrates that the treatment of O2 plasma is an available approach to producing efficient Au-Fe plasmonic nanocatalysts.

Cane Molasses Derived N-Doped Graphene Quantum Dots: Dynamic Quenching Synergistically Photoinduced Electron Transfer for the Instant Detection of Nitrofuran Antibiotics

The development of a highly selective, simple, and rapid detection method for nitrofuran antibiotics (NFs) is of great significance for food safety, environmental protection, and human health. To meet these needs, in this work, cyan-color highly fluorescent N-doped graphene quantum dots (N-GQDs) were synthesized using cane molasses as the carbon source and ethylenediamine as the nitrogen source. The synthesized N-GQDs have an average particle size of 6 nm, a high fluorescence intensity with 9 times that of undoped GQDs, and a high quantum yield (24.4%) which is more than 6 times that of GQDs (3.9%). A fluorescence sensor based on N-GQDs for the detection of NFs was established. The sensor shows advantages of fast detection, high selectivity, and sensitivity. The limit of detection for furazolidone (FRZ) was 0.29 μM, the limit of quantification (LOQ) was 0.97 μM, and the detection range was 5-130 μM. The fluorescence quenching mechanism of the sensor was explored by fluorescence spectroscopy, UV-vis absorption spectroscopy, Stern-Volmer quenching constant, Zeta potential, UV-vis diffuse reflectance spectroscopy, and cyclic voltammetry. A fluorescence quenching mechanism of dynamic quenching synergized with photoinduced electron transfer was revealed. The developed sensor was also successfully applied for detecting FRZ in various real samples, and the results were satisfactory.

Novel Co3O4-CuO-CuOHF porous sheet for high sensitivity n-butanol gas sensor at low temperature

In this study, porous sheet-like nanostructured Co3O4-CuO-CuOHF composites with great n-butanol sensing properties were synthesized by the biotemplate method and hydrothermal method. The effect of various contents of Co3O4-CuO-CuOHF sensor performance was systematically investigated, in which the best performance was achieved for the composite with 0.03 g Co3O4 addition. The response of the best content Co3O4-CuO-CuOHF composite sensor to 100 ppm n-butanol at 180 ℃ is 120, which is 8 times higher than that of the CuO-CuOHF sensor. The composite sensor has excellent selectivity for n-butanol and responds 3.75–25 times higher to n-butanol than other target gases. It is detectable up to 500 ppb n-butanol and has potential promise for low concentration detection. Furthermore, it has outstanding stability and resistance to humidity. The gas sensing mechanism was analyzed by UV–visible diffuse reflectance spectroscopy, EPR oxygen vacancies and X-ray photoelectron spectroscopy, which indicated that the abundant oxygen vacancies, the physical adsorption of polar hydroxyl bonds, the electronegative fluorine substitution and the special microstructure of the composite contributed to its gas-sensitive performance.

Photo-electrocatalytic based removal of acetaminophen: Application of visible light driven heterojunction based BiVO4/BiOI photoanode

The presence of organic micro-pollutants (OMPs) in wastewater treatment effluents is becoming a major threat to the water safety for aquatic and human health. Photo-electrocatalytic based advanced oxidation process (AOP) is one of the emerging and effective techniques to degrade OMPs through oxidative mechanism. This study investigated the application of heterojunction based BiVO4/BiOI photoanode for acetaminophen (40 μg L−1) removal in demineralized water. Photoanodes were fabricated by electrodeposition of BiVO4 and BiOI photocatalytic layers. Optical (UV–vis diffusive reflectance spectroscopy), structural (XRD, SEM, EDX) and opto-electronic (IPCE) characterization confirmed the successful formation of heterojunction for enhanced charge separation efficiency. The heterojunction photoanode showed incident photon to current conversion efficiency of 16% (λmax = 390 nm) at an external voltage of 1 V under AM 1.5 standard illumination. The application of the BiVO4/BiOI photoanode in the removal of acetaminophen at 1 V (external bias) vs Ag/AgCl under simulated sunlight showed 87% removal efficiency within the first 120 min compared to 66% removal efficiency of the BiVO4 photoanode. Similarly, combining BiVO4 and BiOI exhibited 57% increase in first order removal rate coefficient compared to BiVO4. The photoanodes also showed moderate stability and reusability by showing 26% decrease in overall degradation efficiency after three cycles of each 5 h experiment. The results obtained in this study can be considered as a stepping stone towards the effective removal of acetaminophen as an OMP present in wastewater.

Electronic structure characterization of TiO2-II with the α-PbO2 structure by electron-energy-loss-spectroscopy and comparison with anatase, brookite, and rutile

TiO2-II is a high pressure form of titania with a density about 2% larger than that of rutile. In contrast to the common polymorphs anatase, brookite and rutile its electronic structure and optical properties are poorly characterized. Here we report on a comparative electron-energy-loss-spectroscopy (EELS) study for which high resolution valence-loss and core-loss EELS data were acquired from nanocrystalline (<75 ​nm sized) titania particles with an energy resolution of about 0.2 ​eV. Electronic structure features revealed from titanium L3,2 and oxygen K electron energy loss near-edge structures show a strong similarity of TiO2-II with both rutile and brookite, which is attributed to similarities in the connectivity of octahedral TiO6 units with neighboring ones. From combined valence-loss EELS and UV-VIS diffuse reflectance spectroscopy data the band gap of TiO2-II was determined to be indirect and with a magnitude of ∼3.18 ​eV, which is very similar to anatase (indirect, ∼3.2 ​eV), and distinctly different from rutile (direct, ∼3.05 ​eV) and brookite (direct, ∼3.45 ​eV).

Experimental and theoretical study of synthesis and properties of Cu2O/TiO2 heterojunction for photoelectrochemical purposes

The Cu2O/TiO2 heterojunction is an attractive surface for its optoelectronic properties for developing catalysts, cells, and solar devices. However, the mechanisms involved in synthesizing an electrode using the Cu2O/TiO2 heterojunction can affect the surface properties and the surface/electrolyte interactions. In this work, we studied the formation mechanism of the Cu2O/TiO2 heterojunction by electrochemical deposition (ECD) of Cu2O molecules on TiO2 nanoparticles previously deposited on a fluorine-doped thin oxide coated glass substrate (FTO). The photoelectrochemical properties of the Cu2O/TiO2/FTO electrode were characterized by XRD, FE-SEM, TEM, EDX, UV–vis diffuse reflectance spectroscopy (DRS), Raman spectroscopy, and electrochemical methods. Theoretical methods such as ab-initio density functional theory calculations and molecular dynamics simulations were used to understand the experimental results. The analysis carried out by theoretical methods allowed us to identify the initial steps of the formation mechanism of Cu2O molecules on TiO2 nanoparticles. Theoretical calculations demonstrated that forming a Cu2O nanowire-like network on the TiO2 nanoparticle matrix favors the charge transfer at the electrolyte/semiconductor interface, promoting the behavior of the electrode as a cathode. Finally, the Cu2O/TiO2/FTO electrode synthesized was used to perform the reduction photoelectrocatalyzed of nitrate to ammonia under illumination with a Xe-Hg arc lamp and applying −0.5 V bias potential (vs Ag/AgCl sat.) to evaluate the performance of the electrode as a cathode.

Preparation and Photocatalytic Properties of Phosphotungstic Acid SiC Composites

Four kinds of PTA SiC photocatalysts with different proportions of PTA were prepared by impregnation from phosphotungstic acid (PTA) and SiC. The photocatalyst was characterized by UV-Vis diffuse reflectance spectroscopy, X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy and scanning electron microscopy. Rhodamine B (RHB) was used as degradation substrate to investigate the photocatalytic degradation performance of the photocatalyst. The results show that the prepared photocatalyst maintains both the support structure of SiC and the Keggin structure of PTA. PTA SiC with 40% mass fraction of PTA had the best photocatalytic degradation performance. When exposed to light for 180 min, RHB can reach 66% of the degradation efficiency and the photodegradation reaction rate constant was 5.21×10−3 min−1. As an active substance, hydroxyl radical plays a decisive role in photocatalytic degradation of RHB.

Enhanced hydrogen production through visible light photocatalysis using 2D MoS2/2D CdS composite

This study seeks to enhance the morphological face contact between 2D molybdenum disulfide (MoS2) nanosheets containing 1T and 2H phases (inhomogeneous) and 2D cadmium sulfide (CdS) sheets/flakes for enhanced charge transfer. The sulfides are synthesized by hydrothermal and solvothermal methods, respectively. MoS2/CdS composites (5, 10, 15, 20, 25 wt.% MoS2) are prepared using a physical method. The 2D forms and compositions of both materials are confirmed by FE-SEM imaging, XRD patterns, and XRF semi-quantitative analysis. XRD patterns also reveal the presence of 1T and 2H phases in MoS2 as well as the similar morphological and crystalline structures of the two sulfides. The adsorption of MoS2 onto the CdS surface has minimal intervention of the latter’s lattice structure as indicated by UV-Vis diffuse reflectance spectroscopy. A hydrogen production rate of 1036.1 µmol gcat-1 h-1 is observed using the 15 wt.% MoS2/CdS composite which was 159 times larger than bare CdS, with photocatalytic retention of about 80 % after 15 hours of use.

Pyrite (FeS2)‐decorated 1D TiO2 nanotubes in a bilayer as a sustainable photoanode for photoelectrochemical water splitting activity

AbstractHerein, FeS2@TiO2 nanotubes photocatalyst was prepared by electrochemical anodization method followed by successive ionic layer adsorption and reaction method, and then finally annealed in a tube furnace for homogenous crystallization. The surface morphology, elemental composition, optical properties, and crystalline structure of the prepared FeS2@TiO2 nanocomposite were found out by performing scanning electron microscopy, energy dispersive X‐ray spectroscopy, X‐ray diffraction, UV–Vis diffuse reflectance spectroscopy, and fluorescence spectroscopy, respectively, while bonds vibrations and various functional groups' presence were analyzed using Raman and Fourier transform infrared spectroscopy. A higher photocurrent density of 1.59 mA/cm2 at 0.3 V versus reference electrode of Ag/AgCl (1.23 V versus reversible hydrogen electrode) using 100 mW/cm2 intensive light source was shown by 15‐FeS2@TiO2 nanotubes (uniformly loaded photoanode) while donor density (ND) of 3.68 × 10−13 cm−3 as compared to pure TiO2 NTs (0.09 mA/cm2), 05‐FeS2@TiO2 NTs (0.19 mA/cm2), 10‐FeS2@TiO2 NTs (0.53 mA/cm2) and 20‐FeS2@TiO2 NTs (0.61 mA/cm2), respectively. The exceptional photoelectrochemical activity results were attributed to the homogenous integration of FeS2 that not only increase the charge separation but also, intensively interacted with the substrate (TiO2 nanotubes), which results in an excellent photoelectrochemical activity.

Synthesis of Novel Zn3V2O8/Ag Nanocomposite for Efficient Photocatalytic Hydrogen Production

In this study, we fabricated Zn3V2O8 and a Ag-modified Zn3V2O8 composite (Zn3V2O8/Ag) by utilizing effective and benign approaches. Further characterization techniques such as powder X-ray diffraction (XRD) and scanning electron microscopy (SEM) were explored to examine the phase and structural properties, respectively, of the synthesized Zn3V2O8/Ag and Zn3V2O8/Ag composite materials. The oxidation states and elemental composition of the synthesized Zn3V2O8/Ag and Zn3V2O8/Ag were characterized by adopting X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray spectroscopy (EDX). The optical band gaps of the synthesized Zn3V2O8/Ag and Zn3V2O8/Ag were examined by employing ultraviolet–visible (UV-vis) diffuse reflection spectroscopy. HRTEM images clearly show that ZnV@Ag NC has a hexagonal plate-like morphology. Subsequently, Zn3V2O8 and Zn3V2O8/Ag were used as photocatalysts for photocatalytic hydrogen (H2) production. It was observed that after Ag doping, the energy band gap of ZnV was reduced from 2.33 eV to 2.19 eV. EDX mapping images also show the presence of Ag, O, Zn, and V elements and confirm the formation of ZnV@Ag NC with good phase purity. Observations clearly showed the presence of excellent photocatalytic properties of the synthesized photocatalyst. The Zn3V2O8/Ag photocatalyst exhibited H2 generation of 37.52 µmolg−1h−1, which is higher compared to pristine Zn3V2O8. The Zn3V2O8/Ag photocatalyst also demonstrated excellent reusability, including decent stability. The reusability experiments suggested that ZnV@Ag NC has excellent cyclic stability for up to six cycles.

Cascade Reaction of Ethanol to Butadiene over Ag-Promoted, Silica- or Zeolite-Supported Ta, Y, Pr, or La Oxide Catalysts

Ethanol converts to 1,3-butadiene in the presence of suitable multifunctional catalysts. In this work, Lewis acid cations Ta, Y, Pr, and La were dispersed on amorphous silica or β zeolite, and after physically mixing with silica-supported Ag nanoparticles, were tested in the cascade reaction of ethanol to butadiene at 573 K. The Lewis acid catalysts were characterized by X-ray fluorescence, N2 physisorption, scanning transmission electron microscopy (STEM), X-ray diffraction, and diffuse reflectance (DR) UV–vis and X-ray photoelectron spectroscopies. High-resolution STEM images confirmed the small oxide cluster size on the silica support. Results from DR UV–vis spectroscopy showed that zeolite-supported Ta and Pr catalysts had a smaller metal oxide cluster size, relative to their SiO2 counterparts. X-ray photoelectron spectroscopy confirmed that the oxidation state of the cations supported on the zeolite remained the same as that of their SiO2-supported analogues. The selectivity of the C4 coupling products toward butadiene relative to butanol correlated with the acid strength of the Lewis acid cations, as evaluated by the 2-propanol decomposition reaction to propene and acetone, with Ta being the most selective. The rate of C–C coupling over the zeolite-supported cations was enhanced by an order of magnitude compared to those cations supported on amorphous SiO2.

Predicting the catalytic performance of Nb-doped nickel oxide catalysts for the oxidative dehydrogenation of ethane by knowing their electrochemical properties

In the present article, a relationship between the catalytic performance in the oxidative dehydrogenation of ethane (ODHE) for Nb-doped NiO catalysts and their electrochemical properties has been proposed. To do so, highly stable and selective Nb-doped NiO catalysts for the ODHE to ethylene have been synthesized by optimizing synthesis parameters such as the amount of oxalic acid in the synthesis gel and the calcination temperature. These catalysts have been characterized by means of XRD, HRTEM, Raman and UV–vis diffuse reflectance spectroscopies, TPR and XPS. Moreover, Electrochemical Impedance Spectroscopy (EIS), capacitance measurements (Mott-Schottky analysis) and cyclic voltammetries studies were also carried out. Electrochemical characterization indicates changes in the type of semiconductivity: p-type for samples calcined at 350 °C and the sample prepared in the absence of oxalic acid and calcined at 500 °C, to n-type for samples prepared in the presence of oxalic acid in the synthesis gel and calcined at 500 °C. According to the obtained results, the most selective catalysts present a low Nb-incorporation on the NiO lattice with a large amount of tiny Nb2O5 nanoparticles covering NiO crystallites. This work presents, for the first time, a complete electrochemical characterization of Nb-doped NiO catalysts showing a correlation between electrochemical properties and catalytic performance.

The Effect of Titanium Oxyfluoride Morphology on Photocatalytic Activity of Fluorine-Doped Titanium(IV) Oxide

Titanium oxyfluoride (TiOF2) is a metastable product that can be obtained in a fluorine-rich environment. This material can also be a valuable precursor in the synthesis of titanium(IV) oxide (TiO2). However, the effect of TiOF2 morphology on the physicochemical properties of TiO2 has not been studied so far. In this work, single-phase TiOF2 was prepared by a solvothermal method. The as-synthesized samples exhibited a variety of morphologies, including different shapes and crystallite sizes. These materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDS), surface area measurements, thermal gravimetric analysis (TGA) and UV–vis diffuse reflectance spectroscopy (DR/UV–vis). Furthermore, TiOF2 samples were used as precursors in the synthesis of fluorine-doped titanium(IV) oxide and applied in photocatalytic phenol degradation under UV-vis light. The experiments showed that the crystallite size of the precursor, as well as the number of fluoride ions used in the synthesis, were the predominant factors that affected the photocatalytic activity of the final photocatalyst.

Synthesis, characterization of BiOI/rGO nanocomposite and its photocatalytic functionality analysis under visible light

Visible light responding pristine BiOI and BiOI/rGO nanocomposites were prepared using hydrothermal method. The physicochemical characteristics of BiOI and BiOI/rGO composite were studied through X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), high resolution transmission electronmicroscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and UV–vis diffuse reflectance spectroscopy (UV–vis-DRS) techniques. The photocatalytic performance of the synthesized material was analysed against Methylene Blue dye. The photocatalytic activity of BiOI, and BiOI/rGO revealed the degradation of MB about 68 % and 92 %, respectively for a period of 60 min which indicated the enhancement of degradation efficiency for BiOI/rGO compared to BiOI.

A comparative study of band gap engineered in-situ and ex-situ MWCNTs/TiO2 heterostructures for their enhanced photocatalytic activity under visible light

Organic pollutants, such as various types of organic dyes coming out from the textile industries, are polluting surface and groundwater resources alarmingly and posing a threat to aquatic ecosystems. So, the demand for visible-light-driven high-performance photocatalysts having high activity and structural stability is a need of an hour. TiO2 has been one of the well-known and most studied semiconductor photocatalysts for decades. But its low electron-hole pair (e-/h+) recombination time reduces its efficiency, and the large band gap restricts its use as a visible-light-driven photocatalyst. To overcome these limitations of TiO2, herein, we have reported an in-situ and ex-situ MWCNTs modified TiO2 heterostructure nanocomposites photocatalyst and established a comparative study in terms of their ability to degrade methylene blue (MB) dye under visible light irradiation. The as-synthesized in-situ CNTs-TiO2 nanocomposite and ex-situ CNTs-TiO2 nanocomposite were characterized structurally, morphologically, compositionally, and optically through various characterization techniques such as XRD, RAMAN, SEM, XPS, FTIR, and UV–Vis diffuse reflectance spectroscopy. The result reveals the band gap tuning in the in-situ and ex-situ CNTS-TiO2 nanocomposites as a result of increasing MWCNTs concentration. The in-situ CNTs-TiO2-2 nanocomposite has high degradation efficiency (94% in 150 min) and stability due to smooth and strong chemical interactions between the MWCNTs and TiO2, while ex-situ CNTs-TiO2-20 with 10 times more MWCNTs concentration (by weight) as compared to MWCNTs concentration in in-situ CNTs-TiO2-2, exhibits degradation efficiency of 89% in 150 min. The possible degradation mechanism to degrade MB dye has also been put forward.

Composites of Lignin-Based Biochar with BiOCl for Photocatalytic Water Treatment: RSM Studies for Process Optimization

Textile effluents pose a massive threat to the aquatic environment, so, sustainable approaches for environmentally friendly multifunctional remediation methods degradation are still a challenge. In this study, composites consisting of bismuth oxyhalide nanoparticles, specifically bismuth oxychloride (BiOCl) nanoplatelets, and lignin-based biochar were synthesized following a one-step hydrolysis synthesis. The simultaneous photocatalytic and adsorptive remediation efficiency of the Biochar-BiOCl composites were studied for the removal of a benchmark azo anionic dye, methyl orange dye (MO). The influence of various parameters (such as catalyst dosage, initial dye concentration, and pH) on the photo-assisted removal was carried out and optimized using the Box-Behnken Design of RSM. The physicochemical properties of the nanomaterials were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, thermogravimetric analysis, nitrogen sorption, and UV-Vis diffuse reflectance spectroscopy (DRS). The maximum dye removal was observed at a catalyst dosage of 1.39 g/L, an initial dye concentration of 41.8 mg/L, and a pH of 3.15. The experiment performed under optimized conditions resulted in 100% degradation of the MO after 60 min of light exposure. The incorporation of activated biochar had a positive impact on the photocatalytic performance of the BiOCl photocatalyst for removing the MO due to favorable changes in the surface morphology, optical absorption, and specific surface area and hence the dispersion of the photo-active nanoparticles leading to more photocatalytic active sites. This study is within the frames of the design and development of green-oriented nanomaterials of low cost for advanced (waste)water treatment applications.

4,4'-(Anthracene-9,10-diylbis(ethyne-2,1-diyl))bis(1-methyl-1-pyridinium) Lead Iodide C30H22N2Pb2I6: A Highly Luminescent, Chemically and Thermally Stable One-Dimensional Hybrid Iodoplumbate.

A new one-dimensional hybrid iodoplumbate, namely, 4,4'-(anthracene-9,10-diylbis(ethyne-2,1-diyl))bis(1-methyl-1-pyridinium) lead iodide C30H22N2Pb2I6 (AEPyPbI), is reported here for the first time with its complete characterization. The material exhibits remarkable thermal stability (up to 300 °C), and it is unreactive under ambient conditions toward water and atmospheric oxygen, due to the quaternary nature of the nitrogen atoms present in the organic cation. The cation exhibits strong visible fluorescence under ultraviolet (UV) irradiation, and when its iodide is combined with PbI2, it forms AEPyPb2I6, an efficient light-emitting material, with a photoluminescence emission intensity comparable to that of high-quality InP epilayers. The structure determination was obtained using three-dimensional electron diffraction, and the material was extensively studied by using a wide range of techniques, such as X-ray powder diffraction, diffuse reflectance UV-visible spectroscopy, thermogravimetry-differential thermal analysis, elemental analysis, Raman and infrared spectroscopies, and photoluminescence spectroscopy. The emissive properties of the material were correlated with its electronic structure by using state-of-the-art theoretical calculations. The complex, highly conjugated electronic structure of the cation interacts strongly with that of the Pb-I network, giving rise to the peculiar optoelectronic properties of AEPyPb2I6. The material, considering its relatively easy synthesis and stability, shows promise for light-emitting and photovoltaic devices. The use of highly conjugated quaternary ammonium cations may be useful for the development of new hybrid iodoplumbates and perovskites with optoelectronic properties tailored for specific applications.

Ternary Polyaniline@Bi2O3-BiOCl Nanocomposites as Innovative Highly Active Photocatalysts for the Removal of the Dye under Solar Light Irradiation.

Ternary PANI@Bi2O3-BiOCl nanocomposites were successfully synthesized during the oxidative polymerization of aniline monomer in the presence of Bi2O3. PANI@Bi2O3-BiOCl nanocomposites were characterized by several analytical techniques, including X-ray diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), N2 physisorption, UV-Vis Diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS). The effective PANI-semiconductor interaction promotes the fast separation and transfer of photogenerated electrons and holes, enhancing the photocatalytic efficiency of the materials towards methylene blue (MB) degradation under solar light irradiation. The best results were obtained by 0.5%PANI@Bi2O3-BiOCl, leading to 80% MB degradation in 2 h, four times higher than pristine Bi2O3-BiOCl. Moreover, 0.5%PANI@Bi2O3-BiOCl maintained stable photocatalytic performances for four cycles without significant activity loss. Various scavengers (isopropyl alcohol, formic acid, and benzoquinone) were used to identify the active species by trapping holes and radicals generated during the photocatalytic degradation process. Finally, a probable photocatalytic mechanism of PANI@Bi2O3-BiOCl photocatalyst was suggested.