Electron transport and visible light absorption in a plasmonic photocatalyst based on strontium niobate

Construction of Ultrathin BiVO4-Au-Cu2O Nanosheets with Multiple Charge Transfer Paths for Effective Visible-Light-Driven Photocatalytic Degradation of Tetracycline

In this study, unique BiVO4-Au-Cu2O nanosheets (NSs) are well designed and multiple charge transfer paths are consequently constructed. The X-ray photoelectron spectroscopy measurement during a light off-on-off cycle and redox capability tests of the photo-generated charge carriers confirmed the formation of Z-scheme heterojunction, which can facilitate the charge carrier separation and transfer and maintain the original strong redox potentials of the respective component in the heterojunction. The ultrathin 2D structure of the BiVO4 NSs provided sufficient surface area for the photocatalytic reaction. The local surface plasmon resonance (LSPR) effect of the electron mediator, Au NPs, enhanced the light absorption and promoted the excitation of hot electrons. The multiple charge transfer paths effectively promoted the separation and transfer of the charge carrier. The synergism of the abovementioned properties endowed the BiVO4-Au-Cu2O NSs with satisfactory photocatalytic activity in the degradation of tetracycline (Tc) with a removal rate of ≈80% within 30 min under visible light irradiation. The degradation products during the photocatalysis are confirmed by using ultra-high performance liquid chromatography-mass spectrometry and the plausible degradation pathways of Tc are consequently proposed. This work paves a strategy for developing highly efficient visible-light-driven photocatalysts with multiple charge transfer paths for removing organic contaminants in water.

Thickness-dependent optical properties of low-loss transdimensional plasmonic Sr0.82NbO3 thin films

To develop alternative plasmonic materials for nanophotonic applications, the thickness-dependent optical properties of ultrathin plasmonic Sr0.82NbO3 (SNO) films deposited on MgO are investigated. As the thickness decreases from 10 to 2 nm, the film exhibits less metallic, epsilon-near-zero (ENZ) wavelength redshift and higher optical loss due to increased scattering. Nevertheless, the thinnest film still has a high carrier concentration of 1022 cm-3, and the real part of the dielectric functions of all films is less than zero in the near-infrared (NIR) wavelength region, indicating that the samples possess relatively high metallicity and plasmonic characteristics in the NIR. It is found that the carrier concentration dominates the electron effective mass and Drude plasma frequency. Although Au is a commonly used plasmonic material, at a wavelength of 1550 nm, the loss of SNO is 85.8% lower than that of Au, and its plasmonic performance metrics is significantly higher than TiN, Al:ZnO and Sn:In2O3, demonstrating the great potential of SNO in NIR plasmonic device applications.

Tuning the Transparency Window of SrVO3 Transparent Conducting Oxide

Correlated transparent conducting oxides (TCOs) have gained great attention, because of their unique combination of transparency and metallic character. SrVO3 (SVO) was identified as a high-performance TCO in the visible range. Few studies have investigated band structure engineering through chemical doping to enhance the optical properties of SVO. Here, we use two different strategies by exploiting the band-filling and width of the bands derived from Vanadium to tune the screened plasma frequency ωp* and the interband transition Ep-d energy, corresponding to the optical transparency window edges. For control of the band-filling strategy, it is found that Titanium doped SVO has a wide transparency window, but such a composition does not maintain the high electrical conductivity required for TCO applications. Concerning the bandwidth strategy, the doping of SrVO3 by Calcium shows that ωp* remains located in the IR range (1.12 eV), while Ep-d is blue-shifted into the UV region (3.43 eV) due to reinforced electronic correlations. By an appropriate choice of dopant, we successfully increased the size of the transparency window by around 11% from 1.94 eV (SVO) to 2.30 eV (Calcium-doped SVO), while retaining high conductivity of around 2.30 × 104 (S·cm-1) and high charge carrier density of 2.93 × 1022 cm-3.

Black Ultrathin Single-Crystalline Flakes of CuVP2S6 and CuCrP2S6 for Near-Infrared-Driven Photocatalytic Hydrogen Evolution

The development of new near-infrared-responsive photocatalysts is a fascinating and challenging approach to acquire high photocatalytic hydrogen evolution (PHE) performance. Herein, near-infrared-responsive black CuVP2S6 and CuCrP2S6 flakes, as well as CuInP2S6 flakes, are designed and constructed for PHE. Atom-resolved scanning transmission electron microscopy images and X-ray absorption fine structure evidence the formation of ultrathin single-crystalline sheet-like structure of CuVP2S6 and CuCrP2S6. The synthetic CuVP2S6 and CuCrP2S6, with a narrow bandgap of ≈1.0 eV, shows the high light-absorption edge exceeding 1100 nm. Moreover, through the femtosecond-resolved transient absorption spectroscopy, CuCrP2S6 displays the efficient charge transfer and long charge lifetime (18318.1 ps), which is nearly 3 and 29 times longer than that of CuVP2S6 and CuInP2S6, respectively. In addition, CuCrP2S6, with the appropriate d-band and p-band, is thermodynamically favorable for the H+ adsorption and H2 desorption by contrast with CuVP2S6 and CuInP2S6. As a result, CuCrP2S6 exhibits high PHE rates of 9.12 and 0.66 mmol h-1 g-1 under simulated sunlight and near-infrared light irradiation, respectively, far exceeding other layered metal phospho-sulfides. This work offers a distinctive perspective for the development of new near-infrared-responsive photocatalysts.

Constructing High-Active Surface of Plasmonic Tungsten Oxide for Photocatalytic Alcohol Dehydration

Plasmonic semiconductors with broad spectral response hold significant promise for sustainable solar energy utilization. However, the surface inertness limits the photocatalytic activity. Herein, a novel approach is proposed to improve the body crystallinity and increase the surface oxygen vacancies of plasmonic tungsten oxide by the combination of hydrochloric acid (HCl) regulation and light irradiation, which can promote the adsorption of tert-butyl alcohol (TBA) on plasmonic tungsten oxide and overcome the hindrance of the surface depletion layer in photocatalytic alcohol dehydration. Additionally, this process can concentrate electrons for strong plasmonic electron oscillation on the near surface, facilitating rapid electron transfer within the adsorbed TBA molecules for C-O bond cleavage. As a result, the activation barrier for TBA dehydration is significantly reduced by 93% to 6.0 kJ mol-1, much lower than that of thermocatalysis (91 kJ mol-1). Therefore, an optimal isobutylene generation rate of 1.8 mol g-1 h-1 (selectivity of 99.9%) is achieved. A small flow reaction system is further constructed, which shows an isobutylene generation rate of 12 mmol h-1 under natural sunlight irradiation. This work highlights the potential of plasmonic semiconductors for efficient photocatalytic alcohol dehydration, thereby promoting the sustainable utilization of solar energy.

Tailoring Optical Properties in Transparent Highly Conducting Perovskites by Cationic Substitution

SrMoO₃ , SrNbO₃ , and SrVO₃ are remarkable highly conducting d¹ (V, Nb) or d² (Mo) perovskite metals with an intrinsically high transparency in the visible. A key scientific question is how the optical properties of these materials can be manipulated to make them suitable for applications as transparent electrodes and in plasmonics. Here, it is shown how 3d/4d cationic substitution in perovskites tailors the relevant materials parameters, i.e., optical transition energy and plasma frequency. With the example of the solid-state solution SrV_{1- x} Mo_x O₃ , it is shown that the absorption and reflection edges can be shifted to the edges of the visible light spectrum, resulting in a material that has the potential to outperform indium tin oxide (ITO) due to its extremely low sheet resistance. An optimum for x = 0.5, where a resistivity of 32 µΩ cm (≈12 Ω sq^-1 ) is paired with a transmittance above 84% in the whole visible spectrum is found. Quantitative comparison between experiments and electronic structure calculations show that the shift of the plasma frequency is governed by the interplay of d-band filling and electronic correlations. This study advances the knowledge about the peculiar class of highly conducting perovskites toward sustainable transparent conductors and emergent plasmonics.

Complexed Semiconductor Cores Activate Hexaniobate Ligands as Nucleophilic Sites for Solar‐Light Reduction of CO 2 by Water

Although pure and functionalized solid-state polyniobates such as layered perovskites and niobate nanosheets are photocatalysts for renewable-energy processes, analogous reactions by molecular polyoxoniobate cluster-anions are nearly absent from the literature. We now report that under simulated solar light, hexaniobate cluster-anion encapsulated 30-Ni^II -ion "fragments" of surface-protonated cubic-phase-like NiO cores activate the hexaniobate ligands towards CO₂ reduction by water. Photoexcitation of the NiO cores promotes charge-transfer reduction of Nb^V to Nb^IV , increasing electron density at bridging oxo atoms of Nb-μ-O-Nb linkages that bind and convert CO₂ to CO. Photogenerated NiO "holes" simultaneously oxidize water to dioxygen. The findings point to molecular complexation of suitable semiconductor "fragments" as a general method for utilizing electron-dense polyoxoniobate anions as nucleophilic photocatalysts for solar-light driven activation and reduction of small molecules.

Seeing Structural Mechanisms of Optimized Piezoelectric and Thermoelectric Bulk Materials through Structural Defect Engineering

Aberration-corrected scanning transmission electron microscopy (AC-STEM) has evolved into the most powerful characterization and manufacturing platform for all materials, especially functional materials with complex structural characteristics that respond dynamically to external fields. It has become possible to directly observe and tune all kinds of defects, including those at the crucial atomic scale. In-depth understanding and technically tailoring structural defects will be of great significance for revealing the structure-performance relation of existing high-property materials, as well as for foreseeing paths to the design of high-performance materials. Insights would be gained from piezoelectrics and thermoelectrics, two representative functional materials. A general strategy is highlighted for optimizing these functional materials’ properties, namely defect engineering at the atomic scale.

Carrier extraction from metallic perovskite oxide nanoparticles

We observe the extraction of carriers excited between two types of bands in the perovskite oxide, Sr-deficient strontium niobate (Sr_0.9NbO₃). Sr_0.9NbO₃ exhibits metallic behaviour and high conductivity, whilst also displaying broad absorption across the ultraviolet, visible, and near-infrared spectral regions, making it an attractive material for solar energy conversion. Furthermore, the optoelectronic properties of strontium niobate can easily be tuned by varying the Sr fraction or through doping. Sr-deficient strontium niobate exhibits a split conduction band, which enables two types of optical transitions: intraband and interband. However, whether such carriers can be extracted from an unusual material as such remains unproven. In this report, we have overcome the immense challenge of photocarrier extraction by fabricating an extremely thin absorber layer of Sr_0.9NbO₃ nanoparticles. These findings open up great opportunities to harvest a very broad solar spectral absorption range with reduced recombination losses.

Modifying Metastable Sr1-xBO3-δ (B = Nb, Ta, and Mo) Perovskites for Electrode Materials

The presence of surface/deep defects in 4d- and 5d-perovskite oxide (ABO3, B = Nb, Ta, Mo, etc.) nanoparticles (NPs), originating from multivalent B-site cations, contributes to suppressing their metallic properties. These defect states can be removed using a H2/Ar thermal treatment, enabling the recovery of their electronic properties (i.e., low electrical resistivity, high carrier concentration, etc.) as expected from their electronic structure. Therefore, to engineer the electronic properties of these metastable perovskites, an oxygen-controlled crystallization approach coupled with a subsequent H2/Ar treatment was utilized. A comprehensive study of the effect of the post-treatment time on the electronic properties of these perovskite NPs was performed using a combination of scattering, spectroscopic, and computational techniques. These measurements revealed that a metallic-like state is stabilized in these oxygen-reduced NPs due to the suppression of deep rather than surface defects. Ultimately, this synthetic approach can be employed to synthesize ABO3 perovskite NPs with tunable electronic properties for application into electrochemical devices.

Electrochemical sensing base for hazardous herbicide aclonifen using gadolinium niobate (GdNbO4) nanoparticles-actual river water and soil sample analysis

The present work scrutinized the voltammetric analysis of hazardous herbicide aclonifen (ACF) in actual soil and river water samples utilizing the electrochemical method. The electrochemical sensing device was fabricated for the determination of ACF using gadolinium niobate (GdNbO₄) nanoparticles modified glassy carbon electrode (GCE). The novel GdNbO₄ sensing material was prepared via a simple co-precipitation method. Several characterization techniques (TEM, EDS, XRD, XPS, and BET) were utilized to analyze the structural features of the GdNbO₄. The enhanced electrochemical behavior of GdNbO₄ modified GCE towards ACF was observed compared to bare GCE. The cyclic voltammetry response revealed that the prepared sensor shows the lower negative potential with a dramatic increase in the peak current of ACF compared to bare GCE. In the differential pulse voltammetry, the limit of detection (1.15 nM) and sensitivity (23 μA μM^-1 cm^-2) of the ACF on the GdNbO₄ modified GCE was comparatively superior to the formerly proposed ACF based sensor. This sensor reveals good selectivity, repeatability, reproducibility, and long-term stability. The reliability of the sensor exhibits satisfactory recovery results for ACF detection in river water and soil samples.

Qualitative Approaches Towards Useful Photocatalytic Materials

The long-standing crusade searching for efficient photocatalytic materials has resulted in a vast landscape of promising photocatalysts, as reflected by the number of reviews reported in the last decade. Virtually all of these reviews have focused on quantitative approaches aiming at developing an understanding of the underlying mechanisms behind photocatalytic behavior and the parameters that influence structure–function correlation. Less attention has been paid, however, to qualitative measures around the development and assessment of photocatalysts. These measures will contribute toward narrowing the range of potential photocatalytic materials for widespread applications. The current report provides a critical perspective over some of the main factors affecting the assessment of photocatalytic materials as a code of good practice. A case of study is also provided, where this qualitative analysis is applied to one of the most prolific materials of the last-decade, disorder-engineered, black titanium dioxide (TiO₂).

Electronic and plasmonic phenomena at nonstoichiometric grain boundaries in metallic SrNbO3

Grain boundaries could exhibit exceptional electronic structure and exotic properties, which are determined by a local atomic configuration and stoichiometry that differs from the bulk. However, optical and plasmonic properties at the grain boundaries in metallic oxides have rarely been discussed before. Here, we show that non-stoichiometric grain boundaries in the newly discovered metallic SrNbO₃ photocatalyst show exotic electronic, optical and plasmonic phenomena in comparison to bulk. Aberration-corrected scanning transmission electron microscopy and first-principles calculations reveal that a Nb-rich grain boundary exhibits an increased carrier concentration with quasi-1D metallic conductivity, and newly induced electronic states contributing to the broad energy range of optical absorption. More importantly, dielectric function calculations reveal extended and enhanced plasmonic excitations compared with bulk SrNbO₃. Our results show that non-stoichiometric grain boundaries might be utilized to control the electronic and plasmonic properties in oxide photocatalysis.

Self-Optimized Catalysts: Hot-Electron Driven Photosynthesis of Catalytic Photocathodes

Photogenerated hot electrons from plasmonic nanostructures are very promising for photocatalysis, mostly due to their potential for enhanced chemical selectivity. Here, we present a self-optimized fabrication method of plasmonic photocathodes using hot-electron chemistry, for enhanced photocatalytic efficiencies. Plasmonic Au/TiO₂ nanoislands are excited at their surface plasmon resonance to generate hot electrons in an aqueous bath containing a platinum (cocatalyst) precursor. Hot electrons drive the deposition of Pt cocatalyst nanoparticles, without any nanoparticle functionalization and negligible applied bias, close to the hotspots of the plasmonic nanoislands. The presence of TiO₂ is crucial for achieving higher chemical reaction rates. The Au/TiO₂/Pt photocathodes synthesized using hot-electron chemistry show a photocatalytic activity of up to 2 times higher than that of a control made with random electrodeposited Pt nanoparticles. This light-driven positioning of the cocatalyst close to the same positions where hot electrons are most efficiently generated and transferred represents a novel and simple method for synthesizing complex, self-optimized photocatalytic nanostructures with improved efficiency and selectivity.

Stabilizing the B-site oxidation state in ABO3 perovskite nanoparticles

The stabilization of the B-site oxidation state in ABO3 perovskites using wet-chemical methods is a synthetic challenge, which is of fundamental and practical interest for energy storage and conversion devices. In this work, defect-controlled (Sr-deficiency and oxygen vacancies) strontium niobium(iv) oxide (Sr1-xNbO3-δ, SNO) metal oxide nanoparticles (NPs) were synthesized for the first time using a low-pressure wet-chemistry synthesis. The experiments were performed under reduced oxygen partial pressure to prevent by-product formation and with varying Sr/Nb molar ratio to favor the formation of Nb4+ pervoskites. At a critical Sr to Nb ratio (Sr/Nb = 1.3), a phase transition is observed forming an oxygen-deficient SrNbO3 phase. Structural refinement on the resultant diffraction pattern shows that the SNO NPs consists of a near equal mixture of SrNbO3 and Sr0.7NbO3-δ crystal phases. A combination of Rietveld refinement and X-ray photoelectron spectroscopy (XPS) confirmed the stabilization of the +4 oxidation state and the formation of oxygen vacancies. The Nb local site symmetry was extracted through Raman spectroscopy and modeled using DFT. As further confirmation, the particles demonstrate the expected absorption highlighting their restored optoelectronic properties. This low-pressure wet-chemical approach for stabilizing the oxidation state of a transition metal has the potential to be extended to other oxygen sensitive, low dimensional perovskite oxides with unique properties.

Atomic scale characterization of point and extended defects in niobate thin films

Niobium-based oxides have a wide range of applications owing to their rich crystal and electronic structures. Defects at the atomic scale are always unavoidable and will affect their functionalities, especially when in the form of thin films. Here, atomic resolution scanning transmission electron microscopy and electron energy loss spectroscopy have been performed on various defects (point, line, planar defects and segregated phases) in alkaline and alkaline-earth niobate thin films: CaZrO₃ modified (K, Na)NbO₃ and strontium niobate (SNO), respectively. In CaZrO₃ modified (K,Na)NbO₃ thin films, a tetragonal tungsten bronze phase was found, with a sharp boundary with the perovskite phase. In SNO thin films, several kinds of point defects and antiphase boundaries are commonly observed. In addition, a strongly Sr deficient phase, SrNb₂O₆, precipitates inside the SrNbO₃ phase with a coherent interface. The different oxidation states of Nb in SrNbO₃ and SrNb₂O₆ were revealed from the O K edge. Our characterization of the point defects and extended defects in niobate thin films offers practical guidelines for thin film deposition or discovery of defect-based novel functionalities.

Metal Chalcogenides on Silicon Photocathodes for Efficient Water Splitting: A Mini Overview

In the photoelectrochemical (PEC) water splitting (WS) reactions, a photon is absorbed by a semiconductor, generating electron-hole pairs which are transferred across the semiconductor/electrolyte interface to reduce or oxidize water into oxygen or hydrogen. Catalytic junctions are commonly combined with semiconductor absorbers, providing electrochemically active sites for charge transfer across the interface and increasing the surface band bending to improve the PEC performance. In this review, we focus on transition metal (di)chalcogenide [TM(D)C] catalysts in conjunction with silicon photoelectrode as Earth-abundant materials systems. Surprisingly, there is a limited number of reports in Si/TM(D)C for PEC WS in the literature. We provide almost a complete survey on both layered TMDC and non-layered transition metal dichalcogenides (TMC) co-catalysts on Si photoelectrodes, mainly photocathodes. The mechanisms of the photovoltaic power conversion of silicon devices are summarized with emphasis on the exact role of catalysts. Diverse approaches to the improved PEC performance and the proposed synergetic functions of catalysts on the underlying Si are reviewed. Atomic layer deposition of TM(D)C materials as a new methodology for directly growing them and its implication for low-temperature growth on defect chemistry are featured. The multi-phase TM(D)C overlayers on Si and the operation principles are highlighted. Finally, challenges and directions regarding future research for achieving the theoretical PEC performance of Si-based photoelectrodes are provided.

Anion-Substitution-Induced Nonrigid Variation of Band Structure in SrNbO3- xN x (0 ≤ x ≤ 1) Epitaxial Thin Films

Pervoskite oxynitrides exhibit rich functionalities such as colossal magnetoresistance and high photocatalytic activity. The wide tunability of physical properties by the N/O ratio makes perovskite oxynitrides promising as optical and electrical materials. However, composition-dependent variation of the band structure, especially under partially substituted composition, is not yet well understood. In this study, we quantitatively analyzed the composition-dependent variation of band structure of a series of SrNbO_{3- x}N _x (0 ≤ x ≤ 1.02) epitaxial thin films. Electrical conductivity decreased along with the increase of N content x as a result of an increase in Nb valence from 4+ to 5+. Optical measurements revealed that the N 2p band is formed at a critical composition between 0.07 < x < 0.38, which induces charge-transfer transition (CTT) in the visible-light region. These variations in the band structure were explained by first-principles calculations. However, the CTT energy slightly increased at higher N contents (i.e., lower carrier density) on contrary to the expectation based on the rigid-band-like shift of the Fermi level, which suggests a complex combination of the following band-shifting effects induced by N-substitution: whereas (1) reduction of the Burstein-Moss effect causes CTT energy reduction, (2) enhancement of hybridization between Nb 4d and N 2p orbitals and/or (3) suppression of many-body effects enlarge the band gap energy at larger N content. The band structure variation in perovskite oxynitride as presently elucidated would be a guidepost for future material design.

Two-dimensional amorphous NiO as a plasmonic photocatalyst for solar H2 evolution

Amorphous materials are usually evaluated as photocatalytically inactive due to the amorphous nature-induced self-trapping of tail states, in spite of their achievements in electrochemistry. NiO crystals fail to act as an individual reactor for photocatalytic H₂ evolution because of the intrinsic hole doping, regardless of their impressive cocatalytic ability for proton/electron transfer. Here we demonstrate that two-dimensional amorphous NiO nanostructure can act as an efficient and robust photocatalyst for solar H₂ evolution without any cocatalysts. Further, the antenna effect of surface plasmon resonance can be introduced to construct an incorporate antenna-reactor structure by increasing the electron doping. The solar H₂ evolution rate is improved by a factor of 19.4 through the surface plasmon resonance-mediated charge releasing. These findings thus open a door to applications of two-dimensional amorphous NiO as an advanced photocatalyst.

While photocatalysis offers a means to store solar energy as chemical fuels, photocatalysts typically require crystalline structures and expensive noble-metal cocatalysts. Here, authors prepare 2D amorphous nano-nickel oxide capable of plasmonic, photodriven H₂ evolution without cocatalysts.

Temperature stability of thin film refractory plasmonic materials

Materials such as W, TiN, and SrRuO₃ (SRO) have been suggested as promising alternatives to Au and Ag in plasmonic applications owing to their stability at high operational temperatures. However, investigation of the reproducibility of the optical properties after thermal cycling between room and elevated temperatures is so far lacking. Here, thin films of W, Mo, Ti, TiN, TiON, Ag, Au, SrRuO₃ and SrNbO₃ are investigated to assess their viability for robust refractory plasmonic applications. These results are further compared to the performance of SrMoO₃ reported in literature. Films ranging in thickness from 50 to 105 nm are deposited on MgO, SrTiO₃ and Si substrates by e-beam evaporation, RF magnetron sputtering and pulsed laser deposition, prior to characterisation by means of AFM, XRD, spectroscopic ellipsometry, and DC resistivity. Measurements are conducted before and after annealing in air at temperatures ranging from 300 to 1000° C for one hour, to establish the maximum cycling temperature and potential longevity at elevated temperatures for each material. It is found that SrRuO₃ retains metallic behaviour after annealing at 800° C, while SrNbO₃ undergoes a phase transition resulting in a loss of metallic behaviour after annealing at 400° C. Importantly, the optical properties of TiN and TiON are degraded as a result of oxidation and show a loss of metallic behaviour after annealing at 500° C, while the same is not observed in Au until annealing at 600° C. Nevertheless, both TiN and TiON may be better suited than Au or SRO for high temperature applications operating under vacuum conditions.

Effect of Nb concentration on the spin-orbit coupling strength in Nb-doped SrTiO3 epitaxial thin films

Several oxide materials have attracted much interest for the application in spintronic devices due to unusual properties originating from the strongly correlated orbital and spin degrees of freedom. One missing part in oxide spintronics is a good spin channel featured by strong spin-orbit coupling (SOC) which enables an efficient control of the electron’s spin. We have systematically investigated the dependence of the SOC strength of Sr(Nb_xTi_1−x)O₃ thin films on Nb concentration (n_Nb = 2~20 at. %) as a deeper exploration of a recent finding of the strong SOC in a heavily Nb-doped SrTiO₃ (Sr(Nb_0.2Ti_0.8)O₃) epitaxial film. Apart from a finding of a proportionality of the SOC to n_Nb, we have observed an intriguing temperature dependence of the SOC strength and the anisotropic magnetoresistance (MR) in the intermediate n_Nb region. These phenomena are associated with the temperature dependence of Landé g-factor and the change of the band structure, which is consistent with the result of density functional theory (DFT) calculation.

Crystallinity and lowering band gap induced visible light photocatalytic activity of TiO2/CS (Chitosan) nanocomposites

The inhibition of electrons-holes recombination and enhancement of visible light photocatalytic activity were accomplished by the synthesized TiO₂/CS nanocomposites system. In this present work, the different weight ratio of TiO₂ and chitosan (75:25, 50:50 and 25:75) nanocomposites were synthesized via two-step method. After that, the existing functional groups, size and structure of the nanocomposites system were characterized via FT-IR, TEM and XRD measurements. The band gap of the prepared materials and its excitation and emission spectra were elevated through UV-vis and PL analyses. Moreover, the MO and MB degradation capability of the synthesized TiO₂/CS nanocomposites was optimized, and the outcomes are described in detail.

Fast and scalable synthesis of strontium niobates with controlled stoichiometry

An ionic liquid/dextran blend is used to synthesise strontium niobates with exceptional control over stoichiometry.