Pristine BaTiO3 Research Articles

Efficient enhancement of piezo-catalytic activity of BaTiO3-based piezoelectric ceramics via phase boundary engineering

Piezoelectric catalysis stemmed from lead-free piezoelectric ceramics is an emerging catalytic technology applied extensively in degradation of organic pollutants due to its low energy consumption and non-pollution. However, the dissatisfied catalytic efficiency of lead-free piezoelectric ceramics has constrained their further development and application. Herein, we employ ion doping to modulate the phase boundary construction of BaTiO3-based piezoelectric ceramics (BaTi(1-x)(Zr1/3Sn1/3Hf1/3)xO3, BTZSH-x), and the degradation performances of organic dyes are explored to illuminate the piezo-catalytic mechanism. The ion doping alters the phase boundary of BaTiO3 ceramics and a two-phase coexistence of rhombohedral-orthorhombic is achieved at room temperature in BTZSH-0.04 ceramic. Consequently, the BTZSH-0.04 ceramic exhibits an excellent degradation efficiency of rhodamine B with 97.27% in 60min and a high reaction rate constant of 0.056 min−1 under ultrasonication which is 7.4 times more than that of pristine BaTiO3. This work provides an advisable policy for constructing environmental-friendly piezoelectric materials with glorious piezo-catalytic activity.

First-principles calculations of self-defects on the structural, electronic, and optical properties of BaXO3 (X = Ti, Zr, and Hf) perovskite oxide materials

This study utilizes computational simulations to examine the properties of BaXO3 (X = Ti, Zr, and Hf) perovskite oxide materials with self-defects, including vacancy and interstitial. The investigation focuses on their crystal structure, electronic characteristics, and optical behavior. The results show that the pristine BaTiO3, BaZrO3, and BaHfO3 exhibit p-type semiconductor behavior with varying band gaps. The electronic properties are primarily governed by the orbitals of oxygen and transition metal elements, suggesting potential for precise control of electron transport. Introduction of self-defects enhances the magnetization, making them suitable for magnetic applications. Moreover, these materials demonstrate promising optical properties for energy conversion and storage in the visible light and ultraviolet regions. We expected that these findings offer valuable insights for further research on perovskite oxide materials and their applications, particularly regarding the influence of self-defects during the fabrication process.

First-principles study on lanthanide dopants in BaTiO3

Using first-principles calculation based on density-functional theory and density-functional perturbation theory, the microscopic structure and dielectric properties of Lanthanide (Ln) doped BaTiO3 are investigated. The doped Ln atoms exhibit significant displacement from Ba sites for charge compensation, forming off-centered configurations. This displacement is more pronounced for elements with smaller ionic radii. The change in ionic dielectric constant is strongly correlated with Ln displacement and Ln ion radius. As Ln displacement (ionic radius) increases (decreases), Ln-doped BaTiO3 has a higher ionic dielectric constant. However, regardless of the Ln species, the added Ln reduces the ionic dielectric constant compared to pristine BaTiO3.

Oxygen vacancies-rich BaTiO3 for boosting tribocatalytic degradation of water pollutant by harvesting friction energy

Tribocatalysis for environmental remediation faces ongoing challenges related to elucidating complex mechanistic pathways and achieving efficient performance. Engineering surface oxygen vacancies within material systems holds promise for improving overall tribocatalytic efficiency. Herein, a facile solid-phase reduction method was used to generate oxygen vacancies-rich BaTiO3 (R-BaTiO3). Both the pristine BaTiO3 and R-BaTiO3 can harvest friction energy for further tribocatalytic degradation of RhB. The R-BaTiO3 exhibited remarkably higher degradation rate constant for RhB removal, i.e., 0.177 h−1, than that for the pristine BaTiO3, i.e., 0.0789 h−1. The introduction of oxygen vacancies in R-BaTiO3 reduced the energy bandgap and facilitated effective electron-hole separation, leading to the generation of more reactive oxygen species (•O2− and •OH). Tribo-generated holes were identified as the primary reactive species responsible for RhB degradation, surpassing the contributions of •O2− and •OH. A preliminary reaction mechanism based on both electron transfer and electron citation was proposed. The solid-phase reduction method employed in this study presents a promising way for enhancing tribocatalytic performance by introducing oxygen vacancies.

Effect of Sr substitution on the structural, dielectric and ferroelectric property of BaTiO3

We have performed a comprehensive study to explore the effect of Sr substitution on the structural and ferroelectric properties of BaTiO3(BTO) with compositions Ba1-xSrxTiO3for 0 ⩽x⩽ 1. The room temperature structural investigation inferred that the samples with compositionsx> 0.30 has cubic phase instead of tetragonal as for pristine BTO. The temperature dependent dielectric studies illustrate that all well-known three structural phase transitions of BTO are coming closer to each other and the cubic phase is shifted towards lower temperature with increasing Sr content. The frequency dependent dielectric measurements show that there exists the mesoscopic subdomain, whose relaxation time decreases with increasing Sr concentration. The Sr substitution enhanced the ferroelectric properties and maximum remnant polarization at room temperature is observed for 20% Sr substituted sample. The frequency dependent dielectric measurements illustrate the relaxation which could be due to the mesoscopic subdomain, and its relaxation time decreases with increasing Sr concentration. The frequency dependentP-Emeasurements at room temperature infer that for 30% Sr substituted sample, the ferroelectric domain switching is dominated by the rate of nucleation whereas in other compositions forx< 0.3, it is governed by the domain wall speed. The Raman measurements infer the rearrangement of the domain configuration with Sr substitution. Modification in the intensity of the E(TO4) and A(TO3) Raman modes with electric field is also observed for 30% Sr substituted sample and the origin of this is also discussed.

Synergistic impact of metal/semiconductor (Co@Co3O4) core-shell nanostructures on the structure, electrical, and dielectric properties of BaTiO3-based composites

The synergistic impact of metal/semiconductor nanostructures with controlled size and specific morphology on the structure, electrical, and dielectric properties of BaTiO3-based composites has been investigated. The conductive metal (Co) and semiconductor metal oxide (Co3O4) in the form of core-shell Co@Co3O4 nanoparticles have been used as additives for the first time in the present study. Accordingly, BaTiO3/Co@Co3O4 composite materials with different percentage ratios of 100/0 %, 98/2 %, 95/5 %, 90/10 %, 80/20 %, and 0/100 % have been developed and studied. The prepared ceramic composites were characterized via XRD, SEM, EDX, and impedance analyzer. XRD results revealed the formation of high-purity cubic BaTiO3 phase without any traces of secondary phases, as well as the formation of composite structures when Co@Co3O4 core-shell nanostructures are introduced. No diffraction peaks related to other phases are detected in the composite ceramics. According to SEM and elemental distribution analyses, the Co@Co3O4 core-shell nanoparticles are locally distributed between the BaTiO3 grains and formed 0–3 type composites. The composition- and temperature-dependent dielectric and electrical characteristics were also explored. The incorporation of Co@Co3O4 core-shell nanostructures improved both the mobility of charge carriers and charge carrier density by lowering the barriers that greatly affect polarization in ceramic composites. The electrical conductivity was higher in the composite with a BaTiO3:Co@Co3O4 ratio of 80 %:20 % in comparison to pristine BaTiO3 and other composite ceramics. The dielectric loss tangent (tan δ) is lower for composite ceramics with low additive contents. Furthermore, the resonance maximum in tan δ curves for these samples moves to higher frequencies as temperature increases. Based on Cole-Cole plots, a small and hardly visible suppressed semicircle and a flat line are observed in the studied frequency region. The angle of the semicircles upsurges as the concentration of Co@Co3O4 core-shell nanostructures increases, which can be attributed to the increased inhomogeneity in the composites. The present study may offer some new clues for understanding and developing metal/semiconductor/BaTiO3-based composites.

Enhanced photocatalytic efficiency of BaTiO3 augmented by ZnS nanospheres via Type-II heterojunction for methyl orange degradation

The degradation of organic pollutants is significantly influenced by the recombination of photogenerated electron–hole pair, electron transfer and surface area of a photocatalyst. Barium titanate (BaTiO3) exhibits low photocatalytic activity due to the rapid recombination of photoinduced charge carriers. Hence, the photocatalytic performance of BaTiO3 (BTO) nanoparticles was improved by the construction of heterostructure with the addition of ZnS. BaTiO3 and ZnS were prepared using solid-state metathesis (SSM) and hydrothermal methods, respectively. Subsequently, a series of [(1-x)BaTiO3/(x)ZnS, x = 10, 30, 50 and 70 wt%] heterostructures were successfully constructed through a simple calcination method using pre-prepared BaTiO3 and ZnS. The XRD, FTIR, Raman, XPS and HRTEM analyses revealed the formation of heterostructure between the BTO and ZnS. The positron annihilation lifetime spectroscopy (PALS) results suggest the existence of defects within the materials. To explore the photocatalytic activity, the photodegradation of methyl orange (MO) dye was carried out under UV light illumination for 3 h. Among all the compositions, the heterostructure 70 BaTiO3/30 ZnS (BTZS(70-30)) demonstrated remarkable photocatalytic activity (91.38 %) which is 5.3 times higher than the pristine BTO (17.16 %). The improved photocatalytic activity of heterostructures may result from the effective charge carrier separation facilitated by the type –II band alignment structure between BTO and ZnS, as well as surface defects like oxygen (Vo), and sulphur (Vs) vacancies. The lowest photoluminescence of BTZS (70-30) clearly substantiated the observed high photocatalytic activity. The scavenger outcomes validated that superoxide radicals (•O2−) and holes (h+) played predominant role in the degradation of MO and a detailed explanation was provided for the plausible mechanism.

Ultrasound-triggerennd piezocatalytic conductive Guar gum/PEDOT: PSS/BTO composite hydrogels for bacterial-infected skin wound healing

Open skin wounds are susceptible to infections by multidrug-resistant bacteria, which can lead to delayed wound healing or worsening of symptoms. Therefore, there is an urgent need to develop a comprehensive strategy that addresses bacterial infections while simultaneously promoting wound healing for optimal clinical outcomes. In this study, we aimed to combine the benefits of antibacterial piezoelectric catalysis action and controlled electrical stimulation to promote skin tissue repair. Initially, piezoelectric catalytic BaTiO3(BTO) nanoparticles were coated with polydopamine (PDA) to improve the interface compatibility between inorganic and organic phase. Subsequently, a novel conductive composite hydrogel termed PPGSCH was synthesized by doping PDA@BTO into poly (3, 4-ethylenedioxythiophene) -poly (styrene sulfonate) (PEDOT: PSS) hydrogel. Traditional dye degradation experiments and EPR tests found that PDA@BTO nanoparticles exhibited superior piezoelectric catalytic efficiency compared with the pristine BTO. Rheological tests and electrical conductivity tests demonstrated better electrical adaptability and mechanical stability of PPGSCH. Remarkably, under the synergism of piezoelectricity and electric polarization induced by ultrasound (US), the antibacterial rate of PPGSCH exceeded 90% in vitro. Furthermore, when subjected to 0.5 W/cm2 US irradiation, it can generate moderate levels of reactive oxygen (ROS) and micro current, promoting the proliferation and migration of mouse fibroblasts. Animal experiments on infected skin wounds in mice showed that PPGSCH could reduce inflammation, accelerate angiogenesis, and ultimately expedite the infected wound healing. This work opens up new possibilities for enhancing the repair of infected skin wounds.

Improvement in the dielectric, magnetic, ferroelectric, and magnetoelectric coupling attributes of BaTiO3/CoNb0.02Fe1.98O4 composite systems

The search for new materials and compositions, in which the phenomena of ferrimagnetism and ferroelectricity are closely coupled, is of great technological interest. In the present study, composite systems of (BaTiO3)(100-x)%/(CoNb0·02Fe1·98O4)x% where x = 0, 2, 5, 10, 20, and 100% were produced. Initially, BaTiO3 (BTO) was made by sol-gel combustion approach and CoFe1·98Nb0·02O4 (CoFeNbO) was made by hydrothermal method. Both compounds were then combined via solid-state reaction route to form the composite systems. According to X-ray diffraction, the pristine BTO and CoNbFeO display tetragonal and cubic structures, respectively, and all composite systems consisted of the cubic phase for BTO and spinel phase for CoNbFeO. Scanning electron microscopy showed a decrease in grain size (from 0.552 μm to 0.194 μm) and porosity (from 18.65% to 4.57%) as the CoNbFeO content increases from x = 0 to x = 20%, respectively. The influence of magnetic CoNbFeO content on the magnetic, ferroelectric, magnetoelectric coefficient, electric, and dielectric properties of composite systems has been investigated. The ferromagnetic and ferroelectric natures of diverse composite systems are reflected via the registered M-H and P-E loops at ambient temperature. A steady increase in magnetic parameters such as saturation magnetization and remanent magnetization is observed as the spinel ferrite CoNbFeO content increases. Similarly, the values of the electric coercivity increased from 1.65 kV/cm for x = 0% to 3.99 kV/cm for x = 20%. The frequency-dependent dielectric and electrical measurements were also investigated at various temperatures. By raising the measurement temperature, the dielectric polarization was found to increase for composite systems with x > 2%. Interestingly, the tangent loss was reduced for different composite systems in comparison to pristine BTO and CoNbFeO materials. The lowest tangent loss values were noticed for x = 5% composite system. All composite systems revealed good magnetoelectric coupling with coupling coefficient magnitudes up to a maximum value of ∼22.5 mV/cm.Oe, indicating that they can be potential candidates for use in advanced multifunctional electric devices.

Synthesis and optical characterization of Fe doped Barium Titanate (BaTiO3) nanoparticles

The perovskite family includes a variety of titanates used in a variety of electrical ceramic applications such as electronic, electro-optical and electro-mechanical ceramic applications. Barium Titanate (BaTiO3) is a member of a large family of compounds with the general formula ABO3 called perovskites. This paper includes the study of the properties of pristine and Iron (Fe) doped Barium Titante (BTO) at different concentrations synthesized using the sol–gel method. The concentration of dopants varies from 0 to 3 mol% in the specimens. The structural, surface morphology and optical properties of pure and Fe ion doped Barium Titanate nanoparticles have been investigated using X-ray diffraction (XRD), UV–Visible spectroscopy and Photoluminescence spectroscopy. X-ray diffraction (XRD) was used to study the structure and crystallite size of BTO nanoparticles. The results from X-Ray diffractogram shows that the particle size lies in the range 23 to 29 nm. Lattice strain of each samples were calculated using Williamson-Hall plot (WH plot). Bandgap energy of the samples were calculated using UV– Visible spectroscopy. For pristine BaTiO3 the bandgap is found to be 3.23 eV. It is observed that as the doping percentage increases the bandgap of the material decreases. Photoluminescence measurements revealed that the specimen show ultraviolet emission along with emission in blue region.

Sonophotocatalytic water splitting by BaTiO3@SrTiO3 core shell nanowires

Sonophotocatalysis has garnered significant attention due to its potential to enhance advanced oxidation processes, particularly water splitting, by employing materials with combined sonocatalytic and photocatalytic properties. In this study, we synthesized and investigated core–shell BaTiO3@SrTiO3 nanowires (BST NWs) with varying Sr/Ba molar ratios (2.5:7.5, 5.0:5.0, 7.5:2.5 mM, denoted as BST-1, BST-2, and BST-3, respectively) as catalysts for hydrogen production through water splitting. The piezoelectric nanowires demonstrated hydrogen evolution via both sonocatalysis and photocatalysis. In the sonophotocatalysis process, the ultrasonic vibration induced mechanical forces on the BST nanowires, thereby establishing a built-in electric field. This built-in electric field facilitated the effective separation of photo-generated charge carriers and prolonged their lifetimes, leading to a synergistic enhancement of hydrogen evolution. The pristine BaTiO3 and SrTiO3 nanowires exhibited relatively low hydrogen evolution rates (HER) of 7.0 and 6.0 µmol·g−1min−1, respectively. In contrast, the core–shell nanowires exhibited a substantial improvement in the hydrogen evolution rate. The HER increased with the addition of Sr, and BST-1, BST-2, and BST-3 achieved HERs of 12.0, 13.5, and 18.0 µmol·g−1min−1, respectively. The superior performance of BST-3 nanowires can be attributed to their highest piezoelectric potential and largest surface area. Additionally, BST-3 nanowires demonstrated remarkable stability over multiple cycles, validating their practical applicability as efficient photocatalysts.

Investigation of process parameters for solar fuel production using earth-abundant materials

Photoreduction of CO2 to solar fuels and chemicals offers a sustainable method to produce net zero energy vectors. For large-scale applications, it is crucial to develop an improved understanding of the influence of reaction conditions on the design and optimisation of the photoreactor. The performance of CuO impregnated on BaTiO3 photocatalyst was investigated and compared to pristine BaTiO3, and CuO impregnated on commercial P25 (CuO/P25) and ZnO. The influence of irradiance, CO2 and H2O flow and partial pressure, and CO2/H2O ratio on the product yield and selectivity were examined. Using Design of Experiments and Computational Fluid Dynamic modelling, the optimised reaction conditions were irradiance of 125 mW cm−2, with a CO2 flow of 0.09 mL min−1, and water bubbler temperature of 25 °C. At these conditions, a 2 and 10-fold increase of CO and CH4 production, respectively, were obtained, compared to baseline conditions as well as exhibited the highest CO and CH4 production rate compared to previous reports. Among the earth-abundant photocatalysts, CuO/P25 had the highest quantum yield for CH4 (φCH4: 0.47), whilst CuO/BaTiO3 exhibited highest φCO (0.09) and stability for CO production. The under-performing of BaTiO3 and CuO/BaTiO3 was attributed to the presence of amorphous phase in BaTiO3. This work reveals that the combination of catalyst design, reaction engineering, and modelling can improve the efficiencies of CO2 photoreduction.

CO to formaldehyde transformation study on pristine and Au-modified BaTiO3(001) through DFT calculations.

BaTiO3 is one of the most important ferroelectric oxides in electronic applications. Also, it has attractive properties for catalysis that could be used for reducing contamination levels, especially carbon monoxide, CO. CO is one of the main gaseous pollutants generally released from the combustion of fossil fuel. In this work, the CO transformation on pristine and Au-modified BaTiO3 perovskite for H2CO obtention is studied. The CO adsorption and hydrogenation on pristine BaTiO3 leads to formaldehyde synthesis as the most stable product through two possible routes. Furthermore, hydrogenation stages are less probable on pristine BaTiO3. On Au-modified BaTiO3 formaldehyde is the principal product too but Au adatom generates H2CO competition with HCOH. After BaTiO3 modification with Au unpaired electrons were generated. These unpaired electrons are related to the adatom reactivity. According to the obtained results, pristine and Au-modified BaTiO3 can adsorb and hydrogenate CO generating formaldehyde as the principal product. BaTiO3 modifications with Au increase the reactivity of the perovskite in the CO hydrogenation reactions. CO hydrogenation process on Au suggests that further hydrogenation stages beyond formaldehyde are possible. The study was performed through ab initio calculations using the periodic spin-polarized Density Functional Theory (DFT) as implemented in Quantum ESPRESSO. DFT calculations were carried out using the Plane Wave self-consistent field (PWscf). Spin density difference allows us to identify reactive regions related to dangling bonds and unpaired electrons. A plane wave basis set was used to represent the electron states. Vanderbilt pseudopotentials with nonlinear core correction were used to model the ionic cores and valence electrons interaction. Exchange-correlation energies were treated within the generalized gradient approximation (GGA) with the Perdew-Burke-Ernzerhof (PBE) parameterization.

Physical mixing of piezo-electrocatalysts and graphene oxide to promote CO2 conversion

Piezo-electrocatalytic CO2 reduction reaction (PECRR) technique has been verified as an effective CO2-to-fuel conversion strategy by exploiting and utilizing the widely distributed mechanical energy in nature, e.g., blue energy. The facile large-scale preparation of high-performance and low-cost piezo-electrocatalysts is therefore highly desired but challenging. Herein, a method of physical mixing of piezo-electrocatalysts and earth-abundant carbon-based materials is proposed to address the above issue, and we verified this method with typical piezoelectric BaTiO3 and graphene oxide (GO) as a demonstration. With an optimized GO concentration, the BaTiO3 shows a CO yield of 134.4 μmol g−1 h−1 which is about 45.3 % higher than that of pristine BaTiO3. The mechanisms for the enhancement are revealed via boosted piezo-carrier dynamics and charge transfer from BaTiO3 to GO as well as enhanced intrinsic activity. Furthermore, physical mixing of GO is extended to other piezo-electrocatalysts (MoS2, ZnO, ZnS, CdS, Bi2WO6), from which it is found that their performance is improved compared to the counterpart of those without GO. This work suggests that the physical mixing GO is a universal method to improve PECRR performance and may be a decent candidate approach for large-scale preparation of high-performance and low-cost piezo-electrocatalysts in future.

Superexchange-induced Pt-O-Ti3+ site on single photocatalyst for efficient H2 production with organics degradation in wastewater

Efficient photocatalytic H2 production from wastewater instead of pure water is a dual solution to the environmental and energy crisis, but due to the rapid recombination of photoinduced charge in the photocatalyst and inevitable electron depletion caused by organic pollutants, a significant challenge of dual-functional photocatalysis (simultaneous oxidative and reductive reactions) in single catalyst is designing spatial separation path for photogenerated charges at atomic level. Here, we designed a Pt-doped BaTiO3 single catalyst with oxygen vacancies (BTPOv) that features Pt-O-Ti3+ short charge separation site, which enables excellent H2 production performance (1519 μmol·g-1·h-1) while oxidizing moxifloxacin (k = 0.048 min-1), almost 43 and 98 times than that of pristine BaTiO3 (35 μmol·g-1·h-1 and k = 0.00049 min-1). The efficient charge separation path is demonstrated that the oxygen vacancies extract photoinduced charge from photocatalyst to catalytic surface, and the adjacent Ti3+ defects allow rapid migration of electrons to Pt atoms through the superexchange effect for H* adsorption and reduction, while the holes will be confined in Ti3+ defects for oxidation of moxifloxacin. Impressively, the BTPOv shows an exceptional atomic economy and potential for practical applications, a best H2 production TOF (370.4 h-1) among the recent reported dual-functional photocatalysts and exhibiting excellent H2 production activity in multiple types of wastewaters.

Infrared light utilization based on pyroelectric effect to improve the efficiency and stability of BaTiO3 for photocatalytic NO removal

Photocatalysis is a promising method for removing nitrogen oxides outdoor, However, the wide band gap of most photocatalysts usually causes the limited solar spectral response, which hinders the practical application of photocatalysts. In this paper, Sm0.5Sr0.5CoO3(SSC5) with good photothermal conversion performance is combined with BaTiO3 for the effective utilization of sunlight as well as the prohibition of photogenerated carrier recombination. The introduce of SSC5 can rapidly improve the surface temperature of BaTiO3 photocatalyst, which results in the increase of NO activation molecules and the generation of pyroelectric built-in electric field in BaTiO3. Therefore, the photogenerated carrier can be fast migrated and separated. The performance of 3 wt% SSC5/BaTiO3 is improved by 15% compared with the original sample. More interestingly, SSC5/BaTiO3 exhibits good stability compared with pristine BaTiO3. To analyse the reason for the improved stability, the energy of the reaction process on the catalyst surface was also simulate by DFT calculations. The results imply that the increased stability of SSC5/BaTiO3 may rely on the transfer of holes on the BaTiO3 to the SSC5. This study provides some new insights to the design of efficient and stable photocatalysts for NO removal in the environment.

Theoretical description of structural, electronic, elastic, mechanical, and optical response of Ba1−xCdxTiO3 for optoelectronic applications

Barium titanate is well-known oxide-based perovskite with numerous potential applications in optoelectronic and energy storage devices. This manuscript aims to present an ab initio study to correlate effect of changes observed in electronic properties with structural, elastic, mechanical, optical and thermodynamic properties as well as acoustic behavior of Cd decorated barium titanate for optoelectronic applications. Cadmium (Cd) inclusion with varying concentrations (x = 0, 0.11, 0.33, 0.55, 0.77, 1) at Barium site was taken into consideration for a systematic study for the tunable character of material. For DFT study, Cambridge Serial Total Energy Package (CASTEP) under generalized gradient approximation was used. Cd substitution at Ba site has turned out to be effective for fine band gap tuning of barium titanate. The band gap gradually decreases except x = 0.11 and make new end material a conductor. Thus provide a way to design a device for optoelectronic application using a tunable band gap mechanism. To investigate the effect of band gap reduction as well as changes observed in other physical quantities, total and partial densities of states along with elemental density of states were computed. It is evident from the results that Cd surely introduces new states in pristine BaTiO3 (BTO), the main cause of electronic change. The question of stability of material was also addressed using extracted mechanical properties from calculated elastic constants and instituted concentrations separately to satisfyBorn’s stability criteria.Parameters based on Debye temperature and wave velocity calculations were also extracted to investigate thermodynamic and acoustic behavior of system.Optical response was evaluated and presented comparatively. Refractive index and static dielectric function increase to 3.24 and 10.50 respectively with gradual inclusion of Cd concentration. It is evident that the presented materials are not only lead-free for environment-friendly energy storage applications but also a promising candidate for solar cell applications because of ideal band gap range. Moreover, improved optical behavior of these materials is claimed to stand out for optoelectronic applications as well as thermoelectric properties.

Design of a novel Ag-BaTiO3/GO ternary nanocomposite with enhanced visible-light driven photocatalytic performance towards mitigation of carcinogenic organic pollutants

Herein, a novel visible-light responsive, photocatalyst (Ag-BaTiO3/GO) was fabricated by depositing Ag nanoparticles and GO sheets onto the surface of BaTiO3 nanorods via a combination of photodeposition and hydrothermal methods.The as-prepared ternary photocatalyst was comprehensively characterized for its structural, morphological, and optical properties using XRD, XPS, Raman, HR-TEM, FE-SEM, EDS-mapping, BET, EIS,UV–vis DRS, and PL analysis. The photoactivity was assessed by degrading crystal violet dye (CV) and antibiotic ofloxacin (OFL) under visible light illumination. In comparison with pristine BaTiO3, and binary composites Ag-BaTiO3, BaTiO3-GO, the newly designed ternary hybrid exhibited superior activity with ∼ 98.5% and 96.1% degradation efficiency for CV and OFL at high rate constants (0.053 and 0.033 min−1, respectively). The heightened photocatalytic performance is attributed to the SPR effect of Ag, which broadens the visible light range, as well as strong adsorption capacity, excellent electron mobility, and greater surface area of GO that facilitates the charge transfer process. Moreover, the catalyst could be easily reused for four sequential cycles, maintaining up to 78.83% efficiency for CV removal. Trapping experiments disclosed the eloquent role played by the (hydroxyl) OH and O2•- (superoxide) radicals in pollutant degradation. Also, the degradation pathways of CV and OFL were determined based on the LC–MS analysis. TOC test was conducted. Eventually, on account of the results, a photocatalytic reaction mechanism was presumed. This work offers a propitious strategy, for successful eradication of multiple perilous pollutants from wastewater using a combination of metal titanates, plasmonic Ag nanoparticles, and GO based highly efficient ternary photocatalyst.

Hierarchical BaTiO3/NiFe2O4 nanocomposite as an efficacious photoanode for photoelectrochemical water splitting

Photocatalysis of water for the production of oxygen and hydrogen is one of the most important development in the drive for clean energy, and it has received a lot of attention because it is a green and easy step to generate fuels. Developing a more efficient, chemically stable, green and cost-effective catalytic devices for commercial use still remains a challenging task. In this research work, we have designed a new kind of hetero nanostructured hierarchical electrode BaTiO3/NiFe2O4 composite by facile hydrothermal process. The sluggish oxygen-evolving reaction is one of the major challenge in water technology (OER). The prepared photocatalyst exhibited excellent photocatalytic activity towards OER. The prepared electrodes’ physicochemical behaviors have been studied using a variety of spectroscopic techniques include powder X-ray diffraction, UV–Vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy and Transmission electron microscopy. The HR-TEM results of pristine BaTiO3 show partially agglomerated nanoparticles which are in spherical shape with size ranging from 50 to 78 nm, whereas pure NiFe2O4 displays needle-like nanorods with average width and length of the needles are around 31 nm and 1.5 μm respectively and the BaTiO3/NiFe2O4 composite shows combination of nanoparticles with nanorods. XPS analysis has revealed the oxygen vacancies and composition of the materials. The optical band gap investigation showed that the composites Eg value is in the visible region. UV–Vis diffuse reflectance spectroscopy revealed that the hierarchical BaTiO3/NiFe2O4 composite has enhanced absorption in the visible region. The photocatalytic activity results show that, the prepared BaTiO3/NiFe2O4 composite photoelectrode yields a photocurrent density of 0.34 mA/cm2 at 1.6 V vs SCE reference electrode confirms their PEC water splitting ability. These observed findings of the hetero-composite clearly make a way to employ them as the plausible electrode for effectual oxygen evolution reaction.

Tailoring electrocatalytic activity of in situ crafted perovskite oxide nanocrystals via size and dopant control

Perovskite oxides (ABO3) have been widely recognized as a class of promising noble-metal-free electrocatalysts due to their unique compositional flexibility and structural stability. Surprisingly, investigation into their size-dependent electrocatalytic properties, in particular barium titanate (BaTiO3), has been comparatively few and limited in scope. Herein, we report the scrutiny of size- and dopant-dependent oxygen reduction reaction (ORR) activities of an array of judiciously designed pristine BaTiO3 and doped BaTiO3 (i.e., La- and Co-doped) nanoparticles (NPs). Specifically, a robust nanoreactor strategy, based on amphiphilic star-like diblock copolymers, is employed to synthesize a set of hydrophobic polymer-ligated uniform BaTiO3 NPs of different sizes (≤20 nm) and controlled compositions. Quite intriguingly, the ORR activities are found to progressively decrease with the increasing size of BaTiO3 NPs. Notably, La- and Co-doped BaTiO3 NPs display markedly improved ORR performance over the pristine counterpart. This can be attributed to the reduced limiting barrier imposed by the formation of -OOH species during ORR due to enhanced adsorption energy of intermediates and the possibly increased conductivity as a result of change in the electronic states as revealed by our density functional theory-based first-principles calculations. Going beyond BaTiO3 NPs, a variety of other ABO3 NPs with tunable sizes and compositions may be readily accessible by exploiting our amphiphilic star-like diblock copolymer nanoreactor strategy. They could in turn provide a unique platform for both fundamental and practical studies on a suite of physical properties (dielectric, piezoelectric, electrostrictive, catalytic, etc.) contingent upon their dimensions and compositions.