Tetragonal Phase Of BaTiO3 Research Articles

Mechanistic insights into the charge transportation behavior and enhanced photocatalytic performance of BaTiO3/CdS heterostructure by calculations of first-principles and experiments of tracking charge flow direction

Mechanistic insight into charge transportation behavior of the heterogeneous photocatalyst is a key issue to elucidate the photocatalytic performance. This study aims to employ first-principles calculations and tracking charge flow direction to reveal the charge transportation behavior and enhanced photocatalytic performance of CdS modified tetragonal phase BaTiO3 (BTO/CdS). The experiment of X-ray photoelectron spectroscopy and the first-principles calculations confirm the establishment of a built-in electric field and a type-II energy alignment, which are favorable for transport and separation of charge carriers in BTO/CdS heterojunction. The tracking charge flow direction demonstrates that photogenerated electrons of CdS transfer to BTO and photogenerated holes of BTO transfer to CdS. As a result, the constructed BTO/CdS heterojunction nanostructure exhibits substantially enhanced photocatalytic performance. The degradation rate of rhodamine B by BTO/CdS photocatalyst is 98.6 % under simulated light irradiation within 25 min, which is significantly higher than that (29.0 %) of the pure BTO photocatalyst. This study offers a rational strategy to understand the charge transportation behavior and enhanced photocatalytic performance of heterostructures by first-principles calculations and tracking charge flow direction for the design of high-performance photocatalysts.

Rapid Thermal Processing and Improved Photocatalysis of Bi2O3-BaTiO3 Heterojunction

Bi2O3-BaTiO3 heterojunction with high photocatalysis efficiency was directly synthesized by rapid thermal processing (RTP). Bi2O3 and BaTiO3 were mixed in ratio and treated by RTP and conventional thermal processing (CTP), respectively. RTP samples have obvious Bi2O3 diffraction peaks, while CTP samples show pure BaTiO3 tetragonal perovskite. More small particles and layered existed in RTP samples. Photodegradation of MB solutions shows that RTP can promote photocatalytic efficiency. Its main lies in the following points: RTP can remove grain boundary defects by strengthening the bond grains; RTP can limit the solution region of the two substances to a certain range to get the best built-in electric field width; and RTP can strengthen the tetragonal BaTiO3 phase to hasten ion movement. Therefore, RTP can achieve much higher photocatalytic efficiency by improving the build heterojunction. This work provides a direct and efficient route to get improvement and high performance of heterojunction.

Non-hydrolytic sol-gel synthesis of BaTiO3 nano-powder: Effect of calcination temperature and modified titanium source on particles

In this study, BaTiO3 nanopowders were prepared by non-hydrolytic sol-gel (NHSG) method using barium acetate and tetrabutyl titanate (TBT) as precursors and acetylacetone (Hacac) as additive. The effects of acetylacetone modification and calcination temperature on nanoparticle size and crystalline phase were evaluated. The products were analysed by SEM, TEM, DSC/TG, FTIR, XRD, Raman. FTIR analysis showed the formation of Ba-O-Ti bond at the sol stage of the NHSG method. DSC/TG and XRD analyses showed that BaTiO3 was produced at 500 ℃. According to SEM/TEM, the particle size of the powder becomes larger as the temperature increases, meanwhile the addition of acetylacetone can make the final product particle size decrease. Raman analysis showed that BaTiO3 has the presence of tetragonal phase, so the crystalline phases of the product and impurities were analysed by XRD refinement, and the results showed that the relative content of tetragonal phase of BaTiO3 was linearly correlated with the calcination temperature.

Controllable preparation of high tetragonal phase BaTiO3 nano/microstructure and its boosting piezocatalytic properties

BaTiO3 terrace-like nano/microstructure were synthesized via a facile solvothermal method without surfacatant or template by controlling pH value. The phase structure, morphology and properties of the samples were characterized by XRD, FT-IR, XPS, SEM, UV–vis and ESR spectrum, etc. The piezoelectric potential analysis are calculated by finite element method simulation for BaTiO3 prepared at different pH values under ultrasonic vibration. Morphology and crystal phase transform mechanism of BaTiO3 at different pH values are proposed, respectively. The results show that pH value has a significant effect on the phase, crystallinity, morphology, size and piezocatalytic performance of BaTiO3. When pH value is 10, BaTiO3 exhibits spherical shape with an average size of ∼200 nm. With the increase of pH value, the morphology transforms grape-like shape from terrace-like shape. The transformation mechanism for BaTiO3 is proposed to be a two–step growth model: initial nucleation and ripen, an oriented attachement accompanied by Ostwald ripening. H+ ions in OH− group occupy the Ba2+ position and affect the supersaturation of Ti (OH)62−, thereby blocking the migration channel of Ba2+ and changing the crystal symmetry, resulting in changes in the content of tetragonal phase. FEM simulated shows the electric potential of BaTiO3 is dominated by their morphologies. Compared with other samples, the best piezocatalytic performance of BaTiO3 terrace-like nano/microstructure is demonstrated at pH = 12, which is the rate constant k of 15.5 × 10−3 min−1 by degrading 93 % of RhB dye solution in 180min, and keep almost unchanged after five cycles. The attractive piezocatalytic properties are considered to benefit from BaTiO3 terrace-like nano/microstructure, which is composed of the numerous nanounits self-assembly micrometer-scale structure.

Structural Evolution, Dielectric, Ferroelectric and Thermal Properties of Pristine and (Sr, Mn) Co-doped BaTiO3

Nanocrystalline specimen of pure BaTiO3 (BTO) and Ba0.9Sr0.1Ti0.95Mn0.05O3 (BSTMO5) has been synthesized through solid state route. XRD patterns reveal uni-phase tetragonal configuration with P4mm space group. The crystallite size and strain have been evaluated by fitting the data with Williamson-Hall equation. Raman spectra are consistent with the tetragonal phase of BTO. Colossal value of dielectric constant is observed for BTO samples. The temperature-dependent P-E loops reveal highest value of polarization at 323K. Differential thermal analysis (DTA) is used to evaluate the specific heat (Cp) of the samples. Doping with (Sr, Mn) raises the Curie temperature hence enhancing the temperature stability of BTO. It can broaden the temperature range over which the material exhibits desirable ferroelectric and dielectric properties. This improved stability along with high dielectric permittivity is advantageous for applications that require operation over a wide temperature range. The band gap enhanced for BSTMO5 making it suitable for usage in optoelectronic devices.

Piezo-Photocatalytic Degradation of Tetracycline by 3D BaTiO3 Nanomaterials: The Effect of Crystal Structure and Catalyst Loadings

Piezoelectric photocatalysis improves catalytic activity by preventing photogenerated carrier recombination. Hence, three morphologies of BaTiO3 (BTO) were successfully prepared for the piezoelectric photocatalytic degradation of tetracycline (TC, C(TC) = 40 mg/L). The tetragonal-phase BaTiO3 nanoparticles (BTO-NPs) showed the best performance in comparison with cubic-phase nanoflowers (BTO-Nf) and cubic-phase coral-like structures (BTO-Nc) under the same conditions (C(BTO) = 0.6 g/L). When the loading of BTO-NPs was reduced to 0.2 g/L, the photocatalytic degradation efficiency was lowered from 64.2% to 50.1%. However, the 0.6 g/L BTO-NPs increased by only 12.8% after piezoelectricity induction. On the contrary, the BTO-NPs’ degradation effect of 0.2 g/L with the piezoelectric effect was greatly improved from 50.1% to 78.0%, with an increase rate of 27.9%. As the quantity of catalyst was decreased, the increased inter-particle voids made the lattice more susceptible to deformation by external forces, producing a more pronounced piezoelectric effect. These findings indicate that crystal structure and catalyst loading are critical factors in increasing piezoelectric photocatalytic performance. This article emphasizes the application value of piezoelectric photocatalysis in degrading organic pollutants, and provides practical guidelines for optimizing its performance.

Barium titanate perovskite nanoparticles integrated reduced graphene oxide nanocomposite photoanode for high performance dye-sensitized solar cell

Nanocomposites comprised of barium titanate perovskite nanoparticles decorated reduced graphene oxide (BaTiO3-RGO NC) were formed through facile hydrothermal method. X-ray diffractometer profile confirmed crystallite and tetragonal phase of BaTiO3. Identification of D and G bands in Raman investigation and XPS spectra disclosed existence of graphene in the prepared BaTiO3-RGO NC. FE-SEM examination indicates small sized BaTiO3 NPs are obviously decorated on the graphene sheets by strong binding forces between graphene and BaTiO3 NPs. Among graphene of different wt%, BaTiO3-RGO NC with 1.5 wt% showed lowest PL intensity, indicating effective reduction of photogenerated charge carrier recombination. Dye-sensitized solar cell fabricated using BaTiO3-RGO NC photoanode having 1.5 wt% graphene displays high efficiency of 4.93% associated with high photocurrent density.

Multifunctional BaTi0.98M0.02O3 (M = V, Co, Mo) compositions: High dye-photodegradation and relative permittivity characteristics

In this study, the relative permittivity and photocatalytic properties of BaTi0.98M0.02O3 (M = V, Co, Mo) compositions have been investigated. Polycrystalline BaTiO3, BaTi0.98V0.02O3 BaTi0.98Co0.02O3 and BaTi0.98Mo0.02O3 powders were synthesized by solid state reaction method. The X-ray diffraction analysis of all samples confirmed the formation of tetragonal BaTiO3 phase without any impurities. The scanning electron microscope images showed the formation of irregular grains for BaTiO3 and BaTi0.98V0.02O3 samples while BaTi0.98Co0.02O3 and BaTi0.98Mo0.02O3 powders revealed spongy and uniform crystalline grains shapes, respectively. Remarkably, the incorporation of V, Co and Mo ions was reduced the UV band gap energy of BaTiO3 from 3.25 eV to 2.96, 2.98 and 2.92 eV, respectively. These results verify that V, Co and Mo doped BaTiO3 samples have the ability to absorb the visible light spectrum compared to pure one. The study of the dielectric properties showed that the BaTi0.98V0.02O3 and BaTi0.98Mo0.02O3 samples have a colossal relative permittivity of 14263 and 1658, respectively. Besides, BaTi0.98Mo0.02O3 as a photocatalyst exhibits superior photodegradation efficiencies of 90 and 100% towards 10 ppm Congo red solution under sunlight irradiation during 20 and 60 min, respectively. For 50 ppm CR, the photocatalytic activity of this catalyst was reached to 53% and 70% in 20 and 60 min, respectively. The highest performance of BaTi0.98Mo0.02O3 catalyst can be ascribed to high crystallinity, formation of oxygen vacancies, well charge separation and visible light absorption.

Strong alternating piezoelectric field enhanced the piezocatalytic degradation of carbamazepine by a 3-chromophore material Cd4BiO(BO3)3 coupled ultrasound in water

How to efficiently treat a type of new emerging organic pollutant, carbamazepine (CBZ), with the features of environmental persistence, toxicity, and bioaccumulation, is now posing a challenge to scientists. Piezocatalysis, through the harvesting of mechanical energy, has a high capacity to degrade organic pollutants and is gaining increasing attention. Herein, a novel piezo material Cd4BiO(BO3)3 (CBB) with a 3-chromophore asymmetric structure showing an excellent CBZ degradation activity has been synthesized. The removal efficiency can reach 96.2% in 60 min, which is 4.13 times that of tetragonal phase BaTiO3 (BTO) under the same conditions. The superior catalytic performance can be attributed to the easily polarized 3-chromophore asymmetric structure units of CBB, d10 Cd2+ ion, stereochemically active lone pair of Bi3+, and π-delocalization of BO3, which can generate a very strong internal alternating piezoelectric field under the action of ultrasonic vibration. Driven by this internal electric field force, the excited free charges can be easily separated and transferred to the surface of the material to take part in the redox reactions. Besides, CBB also exhibits high stability and excellent removal efficiency for rhodamine B (Rh B) and tetracycline (TC). Hydroxylation and aldehyde oxidation are the main processes of CBZ degradation. The eco-toxicity of CBZ and its intermediates was evaluated using T.E.S.T. software. This study shows that the easily strongly polarized borate material has a potential application in the piezocatalytic degradation of organic pollutants.

Nanostructure Mediated Piezoelectric Effect of Tetragonal BaTiO3 Coatings on Bone Mesenchymal Stem Cell Shape and Osteogenic Differentiation.

In recent years, porous titanium (Ti) scaffolds with BaTiO3 coatings have been designed to promote bone regeneration. However, the phase transitions of BaTiO3 have been understudied, and their coatings have yielded low effective piezoelectric coefficients (EPCs < 1 pm/V). In addition, piezoelectric nanomaterials bring many advantages in eliciting cell-specific responses. However, no study has attempted to design a nanostructured BaTiO3 coating with high EPCs. Herein, nanoparticulate tetragonal phase BaTiO3 coatings with cube-like nanoparticles but different effective piezoelectric coefficients were fabricated via anodization combining two hydrothermal processes. The effects of nanostructure-mediated piezoelectricity on the spreading, proliferation, and osteogenic differentiation of human jaw bone marrow mesenchymal stem cells (hJBMSCs) were explored. We found that the nanostructured tetragonal BaTiO3 coatings exhibited good biocompatibility and an EPC-dependent inhibitory effect on hJBMSC proliferation. The nanostructured tetragonal BaTiO3 coatings of relatively smaller EPCs (<10 pm/V) exhibited hJBMSC elongation and reorientation, broad lamellipodia extension, strong intercellular connection and osteogenic differentiation enhancement. Overall, the improved hJBMSC characteristics make the nanostructured tetragonal BaTiO3 coatings promising for application on implant surfaces to promote osseointegration.

Determination of the temperature dependences of the coefficients of the elastic compliance tensor and the elasticity tensor in the tetragonal phase BaTiO3

A regression analysis of the temperature dependences of the elastic compliance coefficients in the tetragonal phase BaTiO3 has been carried out. Two functions are proposed that have critical temperatures, one of which corresponds to the second to the rest of the coefficients From the obtained analytical dependences, the temperature dependences of the elasticity tensor components in the tetragonal phase are calculated. Formulas for determining the effective coefficient of elasticity and the effective coefficient of elastic compliance are proposed. It is shown that has minims in the near of structural phase transitions in BaTiO3.

Synthesis and Investigation of Ferroelectric Curie Transition in BaTiO3

Ferroelectric phase comprising BaTiO3 nanoparticles and nanorods have been prepared by high temperature sintering. The XRD spectra of sintered powder was used to confirm the ferroelectric phase crystallisation. The non-ferroelectric cubic phase to ferroelectric tetragonal phase transition of BaTiO3 was studied by temperature dependent dielectric study. The Curie temperature of 105 °C in sintered nanoparticles was observed from dielectric study of tetragonal phase BaTiO3.

Electric-field response of polar nanodomains in BaTiO3

In this study, we have investigated the electric-field response of polar nanodomains in the ferroelectric tetragonal phase of BaTiO3. Polar nanodomains were observed by a combination of scanning transmission electron microscopy (STEM) and convergent-beam electron diffraction (CBED). By applying an electric-field, significant changes in the distributions of nanometer-size domains were observed, besides the changes in the configurations of mesoscopic 90° and 180° ferroelectric domains. The obtained CBED patterns are categorized into three. One has higher tetragonal symmetry, and the other two show a deviation from tetragonal symmetry and exhibit a left-right reversal relation with each other. We propose a structural model of the rhombohedral nanodomain redistribution to reproduce the observed CBED patterns. The model consists of a balanced change in volume and size of rhombohedral nanodomains.

Hydrothermal synthesis of barium titanate nano/microrods and particle agglomerates using a sodium titanate precursor

The ion exchange processes and phase formation were studied by varying the properties of 1D barium titanate nanostructures. Temperature-, time- and alkalinity-dependent experiments were performed to study the BaTiO3 formation mechanism involving the generation of chemical sites which induced in situ transformation and dissolution-precipitation reactions occurring in a hydrothermal treatment procedure. As a result of the hydrothermal synthesis, BaTiO3 nano- and microrods with surface nanomaces and nanoparticle aggregates were formed in the temperature range of 160–210 °C, alkalinity range of 0.025–0.15 M and time range of 45–90 min. X-ray diffraction analysis revealed a significant increase in BaTiO3 material purity with increasing alkalinity from 0.025 to 0.15 M, even after a synthesis time of 45 min. In turn, Raman spectroscopy results showed that an increase in the synthesis time allowed not only BaTiO3 purity improvement, but also its phase composition control. The tetragonal phase of BaTiO3 was clearly observed after 6 h of hydrothermal synthesis at 210 °C and various alkalinities (from 0.025 to 0.15 M), while 45 and 90 min resulted in a mixture of cubic or tetragonal phases. Transmission electron microscopy demonstrated that BaTiO3 nanoparticles consisted of mainly tetragonal phases or a mixture of cubic and tetragonal phases, while BaTiO3 nano-/microrods preferably had cubic phases. Thus, variation of the temperature, time and alkalinity upon hydrothermal synthesis allowed the formation of BaTiO3 nano- and microstructures with different morphologies and phase compositions for diverse applications from biomedicine to microelectronics.

Design and fabrication of novel Tb doped BaTiO3 thin film with superior light-harvesting characteristics for dye sensitized solar cells

Herein propose a high performance dye sensitized solar cell based terbium (Tb) doped barium titanate (BaTiO3) thin films prepared by three different techniques such as chemical bath deposition method (CBD), screen printing (SP) and spray pyrolysis coating (SPC) techniques respectively. XRD, SEM and HRTEM results suggest that tetragonal phase of BaTiO3 with three different morphologies like spherical, nanosheets and nanofibers for CBD, SP and SPC assisted Tb:BTO thin films, respectively. Enhancing the visible light absorption, narrowing the band gap energy and prevent the recombination process of electron-hole pair of SPC assisted Tb:BTO thin films were also examined by UV and PL spectra analysis. Moreover, the SPC assisted Tb:BTO thin films show high surface area (102.5 m2/g) and specific porous nature (14.7 nm), studied by N2 adsorption-desorption analysis. Sandwich type DSSC was fabricated and studied the current-voltage characteristic of all the Tb:BTO thin film photoanode samples. The device utilizing in the SPC assisted Tb:BTO thin film photoanode produced the highest photo-conversion efficiency (η) of 15.15% than compared with CBD assisted Tb:BTO (6.57%) and SP assisted Tb:BTO (8.67%). This is due to highest porosity, surface area, lowest leak current and charge transfer resistance Rct of Tb:BTO photoanode. The improved mechanism of the proposed work is also discussed in detail.

Simultaneous normal – Anomalous dielectric dispersion and room temperature ferroelectricity in CBD perovskite BaTiO3 thin films

Chemical bath deposition (CBD) method, being an electroless technique, is used to prepare phase pure barium titanate (BaTiO3) thin films using glass as substrate. Molarity of the solution is varied from 0.1 to 1.2 M, whereas, solution temperature is kept constant at 78 °C. XRD analyses show formation of perovskite tetragonal phase of BaTiO3 at all the molarities when films are annealed at 300 °C. Strengthening in perovskite tetragonal phase is observed with increase in solution molarity. Ellipsometric results show high transmission (∼ 83 %) in the visible region for thin films prepared with 1.2 M solution. Variation in direct band gap, 3.31–3.61 eV, is observed for annealed thin films. High dielectric constant (∼ 539.26 at log f = 3) and low tangent loss is obtained for 1.2 M based thin films. Thin films prepared under all the conditions show normal and anomalous / U-shaped frequency dependent dielectric response (i.e. ∼ 2754.24 at log f = 1.5 and ∼ 2004.73 at log f = 7.5). Maximum spontaneous polarization of ∼ 14.78 μC/cm2 and remnant polarization of ∼ 6.94 μC/cm2 are observed for 1.2 M sample. It is important to mention here that U-shaped high dielectric and good ferroelectric properties of BaTiO3 are observed in current study with no change in perovskite structure of tetragonal phase making it a potential candidate for storage devices at low and high frequencies.

Synthesis of BaTiO3-CuO Mixed Oxides for CO Gas Sensing

Introduction Environmental safety is attracting significant attention due to the increase of dust particles, and toxic gas species (e.g. CO, NOx, etc.) [1]. CO is identified as a major threat for human health. Since CO is a colorless, odorless, and tasteless gas, it can't be detected by human senses. Therefore, sensitive sensor operating in humid air is required for CO gas detection [2]. For metal oxide (MOX) gas sensors, the humidity interferes with the low-level detection of reducing and oxidizing gases. The performances of MOX gas sensors such as SnO2 or CuO can be enhanced, by metal doping, material functionalization or MOX composite [3].In this work, a comparison between resistive sensors based on CuO and on BaTiO3-CuO bi-layer film will be presented. The sensor responses to three CO gas concentrations in dry air and in 50% of relative humidity (RH) will be discussed. Method BaTiO3 nanoparticles (NPs) (<100nm) were dispersed in ethanol by stirring. Copper hydroxide Cu(OH)2 powder (0.2 g) was dissolved in acetic acid (5 ml), water (7 ml) and ethylene glycol (2ml). These two solutions were deposited by drop coating on a silicon oxide substrate provided with interdigitated platinum electrodes (figure 1). CuO films were prepared with one drop of Cu(OH)2 solution. BaTiO3-CuO films were fabricated with one drop of BaTiO3 NPs, an ambient drying for 5 minutes followed by one drop of Cu(OH)2 solution on the top of it. Then, the sensors were annealed at 500°C for 1 h. The sensing properties of these sensors were investigated by CO exposure. NI PXIe-4140 sourcemeter was used to measure the sensor resistance variations for an optimum operating temperature found at 280°C. Results and Conclusions Figure 2 shows the x-ray diffractograms of CuO and BaTiO3-CuO materials. The XRD patterns of CuO film indicate the existence of CuO nanoparticles in the monoclinic phase without CuO2 nanoparticles [4]. BaTiO3-CuO bilayer consists of a tetragonal phase of BaTiO3 in addition to monoclinic CuO [5]. Figure 3 presents the responses of CuO and BaTiO3-CuO to CO gas. In dry air, CuO gives a response equals to 1.22, while the response is more important for BaTiO3-CuO (1.41). In 50% RH, the sensor responses with CuO have almost disappeared while the sensors based on BaTiO3-CuO film gave a response equals to 1.32. Therefore, BaTiO3-CuO films have an enhanced response to CO in dry air as well as in the presence of 50% RH. The CO concentration effect on BaTiO3-CuO films was tested for 10, 50, and 100 ppm of CO in dry air and 50% RH (figure 4). Linear responses under CO in dry or wet air make BaTiO3-CuO bilayer films a potential candidate for the CO gas detection application.We have developed sensors based on BaTiO3-CuO composite for the CO gas detection under dry and wet air. The sensing properties are based on the resistance variation under CO gas. Our results show enhanced responses of BaTiO3-CuO concerning CuO in dry air and 50% RH. Future work will be focused on the proportion of BaTiO3 and CuO investigations to enhance the sensor response under CO.

Preparation of tetragonal barium titanate nanopowders by microwave solid-state synthesis

Tetragonal-phase BaTiO3 powders of particle size 370 nm were synthesized by microwave sintering at 850 °C. The raw materials were BaCO3, TiO2, and alanine. SiC microspheres were used as microwave conductors. The effects of the holding time, sintering aids, and SiC addition on the preparation of BaTiO3 were investigated. The results indicate that the addition of SiC as a microwave acceptor leads to formation of microwave micro-regions. This enables uniform heating of the raw materials and decreases the calcination temperature needed to obtain BaTiO3. Alanine coordinates with Ba, and this loosens the metal–CO3 bond and promotes separation of CO2, decreases the BaCO3 decomposition temperature, and provides a higher nucleation site density. It gives an idea about the microwave solid-state synthesis of BaTiO3 powder.

Temperature induced modulation of near-infrared photoluminescence in BaTiO3:Er

Due to the shielding effect of the outermost electronic layer 5s and 5p of rare earth, the near-infrared photoluminescence (PL) of Er3+ can not be easily affected by the external environment. However, we have regulated the near-infrared PL of Er3+ by changing temperature, which is ascribed to the phase transition of BaTiO3 from tetragonal to cubic phase and the presence of impurity. It also found that the redshift of wavelength in samples containing tetragonal phase BaTiO3 can reach 13 nm, which is never observed in other materials. The center wavelength shifts from 1530 nm to 1543 nm as the temperature rises from 20 to 200 °C. Moreover, the full width at half maximum (FWHM) of samples containing cubic phase has a growth of 6 nm (up to 85 nm) with increasing temperature. It indicated that temperature-induced phase transition can be an important method to modulate the PL of Er3+ in BaTiO3 with impurity.

When C3N4 meets BaTiO3: Ferroelectric polarization plays a critical role in building a better photocatalyst

Photogenerated electrons (e−) and holes (h+) easily undergo fast recombination in many semiconductors, limiting the further improvement of its photocatalytic efficiency. To solve this bottleneck problem, graphitic C3N4 was used to group tetragonal-phase BaTiO3 ferroelectric and successfully constructed the g-C3N4/BaTiO3 heterojunction via a facial mixing-calcination method. These composites exhibited an extraordinary improvement under visible-light irradiation, achieving a “1 + 1>2” performance compared with their single pristine components. It is because the formation of double-transfer structure promotes the fast transfer of photo-induced charge carriers in g-C3N4/BaTiO3 composites. Synergy between the two materials, especially the ferroelectric polarization, plays a key role in facilitating the spatial separation of photo-excited e−/h+ pairs and improving the photocatalytic efficiency.