Barium Titanate Nanoparticles Research Articles

Preparation of High-Performance Barium Titanate Composite Hydrogels by Deep Eutectic Solvent-Assisted Frontal Polymerization.

This study aimed to develop composite hydrogels with exceptional piezoelectric properties and pressure sensitivity. To achieve the objective, this study created a deep eutectic solvent (DES) by mixing choline chloride (ChCl), acrylamide (AM), and acrylic acid (AA). Barium titanate nanoparticles (BTNPs) were incorporated as fillers into the deep eutectic solvents (DES) to synthesize the composite hydrogels using frontal polymerization (FP). The mechanical and piezoelectric properties of the resulting composite hydrogels were analyzed using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). This study found that the BTNPs/P(AM-co-AA) composite hydrogels exhibited excellent mechanical and piezoelectric properties. This is attributed to the high dielectric constant of BTNPs and the electrode polarization phenomenon when subjected to pressure. With a BTNPs content of 0.6 wt%, the maximum compressive strength increased by 3.68 times compared with the hydrogel without added BTNPs. Moreover, increasing the BTNPs content to 0.6 wt% resulted in a 1.48 times increase in generated voltage under the same pressure, compared with the hydrogel with only 0.2 wt% BTNPs. This study provides a method for preparing composite hydrogels with outstanding piezoelectric properties and pressure sensitivity.

Influence of bonding variance on electron affinity in graphene quantum dot-barium titanate nanocomposites for drug delivery system

Although chemotherapy remains a prevalent option in cancer treatment, its adverse effects on normal cells and suboptimal pharmacokinetics often limit its effectiveness. To address these challenges, this study successfully developed a new multifunctional drug delivery system comprising a covalent composite of graphene quantum dots and barium titanate nanoparticles. Notably, despite numerous reports on the surface modification of graphene quantum dots, studies focusing on cancer cell inhibition via different covalent bonds are scarce. To bridge this gap, this system was synthesized using eco-friendly esterification and amidation pathways. The anticancer drug doxorubicin was employed as a model drug, and hyaluronic acid was used to encapsulate the delivery system, enhancing its sustained release capabilities. Comprehensive material characterization confirmed the successful synthesis of the system. Its high drug loading capacity and acid-sensitive release can be attributed to the unique structure of the graphene quantum dots. Subsequent in vitro and in vivo biological evaluations not only demonstrated the system’s remarkable cancer inhibition efficacy but also accentuated the distinct impacts of the two bonding types. The underlying mechanism is believed to involve bonding affinity and electron transfer, findings that are corroborated by the experimental data. Additionally, results from animal models provide clear evidence for the potential application of this system (HA-DOX-GQD@BTNPs) in cancer therapeutics and imaging. In conclusion, this research elucidates the variances in drug carrier efficacy based on different covalent bond modifications for cancer treatment and introduces a novel drug delivery system that synergistically combines imaging and targeting capabilities.

Increased Deep Trap Density in Interfacial Engineered Nanocomposite Revealed by Sequential Kelvin Probe Force Microscopy for High Dielectric Energy Storage.

Nanocomposites combining inorganic nanoparticles with high dielectric constant and polymers with high breakdown strength are promising for the high energy density storage of electricity, and carrier traps can significantly affect the dielectric breakdown process. Nevertheless, there still lacks direct experimental evidence on how nanoparticles affect the trap characteristics of nanocomposites, especially in a spatially resolved manner. Here, a technique is developed to image the trap distribution based on sequential Kelvin probe force microscopy (KPFM) in combination with the isothermal surface potential decay (ISPD) technique, wherein both shallow and deep trap densities and the corresponding energy levels can be mapped with nanoscale resolution. The technique is first validated using the widely-used commercial biaxially oriented polypropylene, yielding consistent results with macroscopic ISPD. The technique is then applied to investigate polyvinylidene fluoride-based nanocomposites filled with barium titanate nanoparticles, revealing higher deep trap density around surface-modified nanoparticles, which correlates well with its increased breakdown strength. This technique thus provides a powerful spatially resolved tool for understanding the microscopic mechanism of dielectric breakdown of nanocomposites.

Enhanced Piezocatalytic Performance of Li-doped BaTiO3 Through a Facile Sonication-Assisted Precipitation Approach.

Piezocatalysis-induced dye degradation has garnered significant attention as an effective method for addressing wastewater treatment challenges. In our study, we employed a room-temperature sonochemical method to synthesize piezoelectric barium titanate nanoparticles (BaTiO3: BTO) with varying levels of Li doping. This approach not only streamlined the sample preparation process but also significantly reduced the overall time required for synthesis, making it a highly efficient and practical method. One of the key findings was the exceptional performance of the Li-doped BTO nanoparticles. With 20 mg of Li additive, we achieved 90 % removal of Rhodamine B (RhB) dye within a relatively short timeframe of 150 minutes, all while subjecting the sample to ultrasonic vibration. This rapid and efficient dye degradation was further evidenced by the calculated kinetic rate constant, which indicated seven times faster degradation rate compared to pure BTO. The enhanced piezoelectric performance observed in the Li-doped BTO nanoparticles can be attributed to the strategic substitution of Li atoms, which facilitated a more efficient transfer of charge charges at the interface. Overall, our study underscores the potential of piezocatalysis coupled with advanced materials like Li-doped BTO nanoparticles as a viable and promising solution for wastewater treatment, offering both efficiency and environmental sustainability.

Synergistic improved piezocatalytic performance of surface group functioned and heterovalently doped barium titanate nanoparticles

Synergistic improved piezocatalytic performance of surface group functioned and heterovalently doped barium titanate nanoparticles

Morphological, and Optical Properties of BaTiO3 Nano Particles

Barium titanate (BaTiO3) nano particles have garnered significant attention due to their unique structural, morphological and optical properties, which hold promise for various technological applications. This study presents a comprehensive investigation in to the synthesis potential of BaTiO3 nano particle. The synthesis of BaTiO3 nano particles was achived through various methods, including sol-gel, hydrothermal, and solvothermal routes, with meticulous control over parameters such as temperature, pH, and precursor concentration to tailor the nano particle size and morphology. The structural characterization using techniques such as x-ray diffraction (XRD) revealed the formation of pure –phase BaTiO3nanoparticles with crystallite sizes in the nanometer range, exhibiting a perovskite strucure. Morphological analysis using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) elucidated the morphology, size distribution, and surface chacteristics of the nano particles. The results showcased well –defined, uniform nano particles with controllable sizes and shapes, ranging from spherical to cubic, depending onthe synthesis conditions. futher more, the optical properties ofBaTiO3 nanoparticles were investigated using UV-visible spectroscopy and photoluminescence spectroscopy. The UV- visible spectra exhibited characteristic absorption peaks corresponding to the electronic transitions within the band structure of BaTio3,while photoluminescence spectra revealed emission peaks indicative of defect states with in the nanoparticle. These optical properties were found to be tunable by varying the nano particle size, morphology, and surface characteristics, offering opportunities for optoelectronic and photonic device applications. The key findings of this study underscore the importance of understanding the interplay between synthesis parameters and resulting structural, morphological, and optical properties of BaTiO3 nanoparticles.

Direct Observation of Carbonate Chemisorption on Barium Titanate Surfaces by Tip‐Enhanced Raman Spectroscopy

AbstractSurface chemistry significantly influences the physicochemical and functional properties of nanoparticles, thus necessitating the investigation of surfaces, especially when subjected to chemisorption. Seeking a method that delivers both high‐resolution imaging and precise chemical information, tip‐enhanced Raman spectroscopy (TERS) emerges as a critical technique. By the combination of scanning probe microscopy with Raman spectroscopy, TERS effectively addresses the limitations of traditional optical microscopes in the study of nanoparticles. The results provide detailed nanoscale structural insights, shed light on surface chemistry, and enable the detection of Raman‐forbidden modes caused by the substantial electric field at the tip apex (≈3 × 108 V m−1). This electric field plays a crucial role in altering selection rules, thereby broadening the scope of TERS beyond merely detecting Raman modes. By combining topographical with TERS mapping, the presence of a carbonate monolayer on the barium titanate (BaTiO3) nanoparticle surface is unveiled – an observation elusive to common characterization techniques.

Investigation of thermodynamical, electro-optical and dielectric properties of nematic liquid crystals dispersed with low-concentration barium titanate nanoparticles

ABSTRACT A liquid crystals nanoparticles composite was prepared by dispersing barium titanate nanoparticles (BT-NPs) into a multi-component liquid crystalline material having wide range room temperature nematic phase. The thermodynamic, optical textures, electro-optical and dielectric properties of the composite sample were studied along with pristine materials. Isotropic to nematic phase transition temperature was enhanced for nano-composites as observed from thermodynamic, optical textures and dielectric investigations. Effect of BT-NPs dispersion on various display parameters of nematic liquid crystals, namely, threshold voltage, dielectric anisotropy, DC conductivity and splay elastic constant has been explored. A relaxation mode in kHz frequency range has been observed for pure and nano-composites samples, which varies with temperature and follows Arrhenius behaviour. DC conductivity enhances approximately fivefold for BT-NPs dispersed samples. The host liquid crystalline material has nematic ordering which supports alignment of BT-NPs parallel to the nematic director which consequently improves thermal stability, dielectric and electro-optical parameters of the nano-composite system.

Dielectric anisotropy changes in MBBA liquid crystal doped with barium titanate by a new method

In response to the burgeoning interest in enhancing the properties of liquid crystal composites, this research systematically explores the intricate interplay between MBBA nematic liquid crystals and ferroelectric barium titanate nanoparticles. The focus is modulating dielectric properties under temperature, frequency, and an applied electric field. Nuanced insights into temperature-dependent behavior, parallel and perpendicular component alterations, and a nonlinear correlation between nanoparticle concentration and dielectric constant are revealed. The study delves into dielectric anisotropy, indicating a reduction with increasing temperature. Structural analyses validate size reduction and crystal phase maintenance of barium titanate nanoparticles (NPs), emphasizing their impact on dielectric characteristics. Frequency-dependent investigations underscore a consistent decline in permittivity with rising frequency across nanoparticle concentrations. Application of an electric field in filling process of liquid crystal cells reveals irregular changes in dielectric constant, holding promise for tailored applications in display technologies. These comprehensive findings offer valuable insights into manipulating dielectric anisotropy properties of MBBA liquid crystal by a simple method for potential advancements in optoelectronic devices and display technologies.

PVDF/PI/BT nanocomposites with excellent charge/discharge efficiency obtained by inserting linear polymer to adjust the ferroelectricity

The problem of low charge/discharge efficiency of ceramic/polymer composites is still one of the hot topics in current research on dielectric materials. Here, we demonstrate that the ferroelectric property of ceramic/PVDF-based composites can be modulated by the introduction of linear polymer PI and the use of a spin-coating process. PI inhibits some polarization and partial dipole orientation by interacting with the molecular chains of the amorphous phase of PVDF and BT nanoparticles. As a result, the decrease in crystallinity and loss led to improved dielectric properties and charge/discharge efficiency. The findings demonstrate that the microstructure of PVDF-PI/BT nanocomposite is uniform and dense, with outstanding dielectric characteristics and high charge/discharge efficiency. The permittivities were stabilized in the range of 12.87–17.86 at 100 Hz, and the dielectric losses were all less than 0.27. Compared with the previously reported binary ceramic/polymer composites, the PVDF-PI/BT nanocomposites possessed a high charge/discharge efficiency with a small variation (63%-84%). This work offers an easy and efficient scheme to obtain nanocomposites with outstanding dielectric characteristics and charge/discharge efficiency. It may be a potential candidate for flexible dielectric substrates for advanced flexible capacitive energy storage devices.

Janus microparticles-based targeted and spatially-controlled piezoelectric neural stimulation via low-intensity focused ultrasound

Electrical stimulation is a fundamental tool in studying neural circuits, treating neurological diseases, and advancing regenerative medicine. Injectable, free-standing piezoelectric particle systems have emerged as non-genetic and wireless alternatives for electrode-based tethered stimulation systems. However, achieving cell-specific and high-frequency piezoelectric neural stimulation remains challenging due to high-intensity thresholds, non-specific diffusion, and internalization of particles. Here, we develop cell-sized 20 μm-diameter silica-based piezoelectric magnetic Janus microparticles (PEMPs), enabling clinically-relevant high-frequency neural stimulation of primary neurons under low-intensity focused ultrasound. Owing to its functionally anisotropic design, half of the PEMP acts as a piezoelectric electrode via conjugated barium titanate nanoparticles to induce electrical stimulation, while the nickel-gold nanofilm-coated magnetic half provides spatial and orientational control on neural stimulation via external uniform rotating magnetic fields. Furthermore, surface functionalization with targeting antibodies enables cell-specific binding/targeting and stimulation of dopaminergic neurons. Taking advantage of such functionalities, the PEMP design offers unique features towards wireless neural stimulation for minimally invasive treatment of neurological diseases.

Influence of core-shell polydopamine-barium titanate doping on the osseointegration and cytotoxicity of the polypyrrole coatings applied by ECD on Nitinol orthopedic implants

In the current study, a thin polydopamine (PDA) layer of around 5 nm was created on the barium titanate (BT) nanoparticles through self-polymerization of dopamine. The produced modified PDA/BT core-shell nanoparticles, termed PBT, were co-electrodeposited with polypyrrole (PPy) onto Nitinol (NiTi) alloy substrates in concentrations ranging from 1 to 10% by weight to produce PPy/PBT composite coatings. The incorporation of these particles changed PPy's cauliflower morphology into a rougher but more compact nodular morphology. According to the atomic force microscopy results, the average surface roughness of PPy coating increased from 44.2 nm up to 80.2 nm by the co-deposition of PBT. Aside from variations in morphology and roughness values, all of the PPy and PPy/PBT coatings demonstrated hydrophilicity. Nonetheless, while the majority of the composite coatings had higher water contact angle (WCA) than the unreinforced PPy, the PPy/10PBT composite coating had the lowest WCA of all samples, measuring 56.9°. The piezoelectric responses of the coatings were also examined, and the best specimen was the PPy/5PBT composite coating with an enhanced output voltage of approximately 400 mV. Finally, MC3T3 mouse osteoblast cells were used for in vitro cell culture evaluations. While healthy cells were evenly distributed on the surface of all coatings after 3 days, indicating biocompatibility, cell density on composite coatings was higher than on unreinforced PPy coating. According to the MTT experiment, the vitality of MC3T3 osteoblast cells on the surface of PPy/5PBT composite coating was more than 30% greater than that on the surface of PPy coating.

3D Printed Piezoelectric BaTiO3/Polyhydroxybutyrate Nanocomposite Scaffolds for Bone Tissue Engineering.

Bone defects are a significant health problem worldwide. Novel treatment approaches in the tissue engineering field rely on the use of biomaterial scaffolds to stimulate and guide the regeneration of damaged tissue that cannot repair or regrow spontaneously. This work aimed at developing and characterizing new piezoelectric scaffolds to provide electric bio-signals naturally present in bone and vascular tissues. Mixing and extrusion were used to obtain nanocomposites made of polyhydroxybutyrate (PHB) as a matrix and barium titanate (BaTiO3) nanoparticles as a filler, at BaTiO3/PHB compositions of 5/95, 10/90, 15/85 and 20/80 (w/w%). The morphological, thermal, mechanical and piezoelectric properties of the nanocomposites were studied. Scanning electron microscopy analysis showed good nanoparticle dispersion within the polymer matrix. Considerable increases in the Young's modulus, compressive strength and the piezoelectric coefficient d31 were observed with increasing BaTiO3 content, with d31 = 37 pm/V in 20/80 (w/w%) BaTiO3/PHB. 3D printing was used to produce porous cubic-shaped scaffolds using a 90° lay-down pattern, with pore size ranging in 0.60-0.77 mm and good mechanical stability. Biodegradation tests conducted for 8 weeks in saline solution at 37 °C showed low mass loss (∼4%) for 3D printed scaffolds. The results obtained in terms of piezoelectric, mechanical and chemical properties of the nanocomposite provide a new promising strategy for vascularized bone tissue engineering.

Horizontally-oriented barium titanate@polydomine/polyimide nanocomposite films for high-temperature energy storage

High-temperature ceramics polymer dielectric nanocomposite materials have broad application prospects in energy storage. The barium titanate (BT) plays an important role as one of outstanding representative ceramics in the dielectric nanocomposite materials. However, there is little known for the effects of two-dimensional (2D) BT morphology and layout on the properties of high-temperature nanocomposite materials. Hence, 2D scale-like BT ceramic fillers were prepared from layered K0.8Li0.27Ti1.73O4 crystals as precursors using a combined solid-state and hydrothermal process. 2D scale-like BT@polydopamine (PDA) core-shell nanocomposites were prepared via coating PDA on the BT. BT@PDA/polyimide(PI) nanocomposite films were fabricated by horizontally oriented distribution of BT@PDA in the PI matrix. The BT@PDA/PI nanocomposite films exhibit a high energy density (3.34 J/cm3) and high charge-discharge efficiency (83.68 %) at 150 °C. It is currently the highest energy storage performance in the BT/PI nanocomposite films at 150 °C. The excellent properties are due to preventing upward breakdown of electrical pathways and promoting dispersion and entanglement of the electrical pathway routes. Additionally, strong electrostatic interactions between the different polymer chains (PDA and PI) restricts the movement of space charges. This work demonstrates that introducing horizontally oriented, organically shell-modified and 2D small-sized BT nanoparticles into a PI matrix is an effective method for improving energy storage performance.

High-Performance All-Textile Triboelectric Nanogenerator toward Intelligent Sports Sensing and Biomechanical Energy Harvesting.

Merging textiles with advanced energy harvesting technology via triboelectric effects brings novel insights into self-powered wearable textile electronics. However, fabrication of a comfortable textile-based triboelectric nanogenerator (TENG) with high outputs remains challenging. Herein, we propose a highly flexible, tailorable, single-electrode all-textile TENG (t-TENG) with both wear comfort and high outputs. A dielectric modulated porous composite coating containing poly(vinylidene fluoride)-hexafluoropropylene copolymer and barium titanate nanoparticles is constructed on conductive fabric to counterpart with highly positive glass fiber fabric through knotted yarn bonding, maintaining the superiority of textiles and strong triboelectricity. Through the synergistic optimization of charge storage via dielectric modulation and charge dissipation offset by electrical poling, remarkable outputs (261 V, 1.5 μA, and 12.7 nC) are obtained from a miniaturized, lightweight t-TENG (2 × 2 cm2, 130 mg) with an instantaneous power density of 654.48 mW·m-2, as well as excellent electrical robustness and device durability over 20,000 cycles. The t-TENG also exhibits a high sensitivity of 3.438 V·kPa-1 in the force region (1-10 N), demonstrating great potential in TENG-based intelligent sports sensing applications for monitoring and correcting the basketball shooting hand and foot arch posture. Furthermore, over 110 light-emitting diode arrays can be lightened up by gently tapping this miniaturized t-TENG. It also offers a wearable power source scheme through integrating the single-electrode device into clothing and utilizing the skin as the grounded electrode, revealing its ease of integration and biomechanical energy harvesting capability. This work provides an attractive paradigm for next-generation textile electronics with well-balanced device performance and wear comfort.

Fabrication and analysis of PVA/V2O5/BaTiO3 nanocomposite film for flexible optoelectronics

Herein, the vanadium pentoxide (V2O5) powder and barium titanate (BaTiO3) nanoparticles (NPs) were incorporated (1 wt % each) into the polyvinyl alcohol (PVA) matrix to fabricate a flexible film using the solution casting. Structural, morphological, elemental and chemical analysis were performed. The UV visible investigations showed a significant drop in the direct bandgap (5.04–2.61 eV), enhancement in the refractive index (1.05–1.95 at 400 nm), excellent rise in the optical conductivity (2.7 × 109 to 1.2 × 1012 S m−1 at 400 nm) after incorporation of V2O5/BaTiO3 NPs into the PVA matrix. The frequency response analysis showed a good rise in the dielectric constant (1.1–3.8 at 1 MHz) and a drop in the dielectric loss (5.4–3 at 10 MHz). Thermal analysis also indicated modifications. Enhancements were found in Young's modulus (210–374 MPa). The fabricated PVA/V2O5/BaTiO3 nanocomposite film might be a potential candidate for optoelectronic devices.

Polyvinylidene Fluoride Based Piezoelectric Composites with Strong Interfacial Adhesion via Click Chemistry for Self-Powered Flexible Sensors.

Achieving relatively uniform dispersion in organic-inorganic composites with overwhelming differences in surface energy is a perennial challenge. Herein, novel eliminated polyvinylidene fluoride (EPVDF)/EPVDF functionalized barium titanate nanoparticles (EPVDF@BT) flexible piezoelectric nanogenerators (PENGs) with strong interfacial adhesion are developed via thermal stretching following sequential click chemistry. Thanks to the strong interfacial adhesion, the optimal PENGs containing ultra-high β-phase content (97.2%) exhibit not only optimized mechanical and dielectric behaviors but also excellent piezoelectric properties with high piezoelectric output (V = 10.7V, I = 216 nA), reliable durability (8000 cycles), ultrafast response time (20ms), and good sensitivity (2.09 nAkPa-1 ), far outperforming most reported PVDF-based composites. Furthermore, COMSOL finite element simulations (FEM) confirm that the elevated stress transfer efficiency induced by the strong interfacial adhesion is the main driving force for enhanced piezoelectric performances. For practical applications, self-powered PENGs can simply but stably capture mechanical energy, drive tiny electronic devices, and serve as potential multifunctional and durable sensors for detecting human physiological motions. This work opens a pioneering avenue to break the trade-offs between piezoelectric and other properties, which is of great importance for developing self-powered flexible sensors.

Synthesis of High‐Performance Polyvinylidene Fluoride Composites via Hydroxyl Anchoring Effect and Directional Freeze‐Drying Method

Polyvinylidene fluoride (PVDF) and its copolymers present extensive application prospects, especially in the field of wearable electronics. However, utilizing nanofillers for enhanced β‐phase and piezoelectric properties faces challenges like noncontinuous interfaces, poor compatibility between nanofillers and PVDF matrix, and the requirement of high‐voltage polarization, hindering extensive domain alignment on a large scale. Herein, a method is proposed to synthesize high‐performance PVDF composites by introducing hydroxylated barium titanate (H@BTO) nanoparticles and a directional freeze‐drying method to enhance β‐phase content and piezoelectric properties without polarization. Molecular dynamics simulations reveal robust binding interactions between Ba and F atoms along with OH surface terminations on H@BTO, facilitating hydrogen bonding within the PVDF matrix, resulting in dipole alignment and increased spontaneous polarization. The composite film achieves an 86.69% β phase content and a piezoelectric coefficient of ≈14.49 pm V−1 without electric polarization. The freeze‐drying PVDF‐H@BTO composite film paired with a PA6 membrane is used to fabricate triboelectric nanogenerator, demonstrating a current density of ≈107.5 mA m−2 and an output voltage of ≈832 V. Results demonstrate that the utilization of strong binding interactions between various atoms, the hydroxyl anchoring effect, and directional freeze‐drying method as a strategy holds promising prospects for synthesizing high‐performance piezoelectric composites.

Silver doped barium titanate nanoparticles for enhanced visible light photocatalytic degradation of dyes

Due to the rapid growth of global population, new, fast and reliable methods must be developed to purify contaminated water. Various photocatalysts have been developed to remove organic dyes from water. Herein, Ag doped BaTiO3 has been synthesized using a facile solvothermal method and its excellent photocatalytic activities were demonstrated in degradation of both anionic and cationic dyes under visible light illumination. Ag doped BaTiO3 nanoparticles showed greater efficacy in the degradation of methylene blue (MB) and eosin yellow (EY) than undoped BaTiO3 nanoparticles, which makes them a better candidate for photocatalysis. 1.0 AgBT sample showed the highest photocatalytic activity for MB (99.1 % in 100 min) and EY (99.3 % in 60 min) dye degradation compared with those of other samples. Further, the trapping experiments revealed that hydroxyl radicals and holes are the active species in the photocatalytic process of MB and EY dye degradation and recycle test showed excellent stability of the synthesized material.

Enhanced photocatalytic degradation of Rhodamine B using gold nanoparticles decorated on BaTiO3 with surface plasmon resonance enhancement.

This study focused on synthesizing and applying gold nanoparticle (Au NP) decorated barium titanate (BaTiO3) nanoparticles for photocatalytic purposes. BaTiO3 NPs were synthesized using a facile hydrothermal method. Various techniques were employed to characterize the structure and morphological characteristics of the prepared materials. The photocatalytic degradation of Rhodamine B over the Au NPs-modified BaTiO3 photocatalysts was studied. Trapping experiments were conducted using different scavengers to elucidate the degradation mechanism and the involvement of photogenerated species. The incorporation of an appropriate amount of Au NPs into the composites resulted in a significant improvement in photocatalytic activity, attributed to the combined effect of Schottky junction at the interface and the surface plasmon resonance of Au NPs.