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Biodiesel has been recognized as the most widely utilized biofuel around the world due to its significant role in reducing the consumption of crude oil and lowering environmental pollution levels. By serving as a renewable alternative to fossil fuels, bioethanol helps decrease greenhouse gas emissions and contributes to a more sustainable energy future. Traditionally, alkali hydroxides like NaOH and KOH have been mainstays in biodiesel synthesis. However, their overuse can lead to unwanted byproducts and operational complexities. Since calcium titanate can occur at a strong base condition, it presents an alternative avenue worth exploring. In this study, we investigate the influence of alkali hydroxides, namely LiOH, NaOH, and KOH, on the formation of calcium titanate through hydrothermal methods, with varying heating times. We aim to understand how different hydroxides affect the synthesis process and the resultant properties of calcium titanate. We delve into the vibrational properties of Ca-O-Ti and Ti-O bonds using Fourier Transform Infra Red (FTIR) spectroscopy, confirming the presence of calcium titanate (JCPDS No.42-0423) through Xray Diffractometry (XRD). This thorough characterization provides insight into the structural integrity and composition of the synthesized materials. Moreover, Scanning Electron Microscopy (SEM) reveals the intriguing cube-like morphology of calcium titanate, offering visual evidence of its unique structure. The fatty acid methyl ester impressively show that calcium titanate synthesized in 7 M NaOH and KOH solutions, heated for 24 h, emerges as a promising biodiesel catalyst. We observe fatty acid methyl ester provides the percentages of 63.67% and 90.02%, respectively, indicating the catalytic efficacy of these materials in biodiesel production. These findings not only contribute to the understanding of calcium titanate synthesis but also pave the way for a sustainable future in biodiesel production by introducing efficient and eco-friendly catalysts. [ABSTRACT FROM AUTHOR]

In this work, the synthesis of Ho3+-doped calcium titanate perovskite (CaTiO3) revealed significant photoluminescence (PL) properties, predominantly displaying a distinct green emission. The investigation explored Ho3+-doped CaTiO3 perovskite synthesized via the sol–gel method. Structural analysis confirmed an orthorhombic crystal structure through powder x-ray diffraction (XRD) and Rietveld refinement, while Fourier transform infrared (FT-IR) spectroscopy confirmed the presence of functional groups in Ho3+-doped CaTiO3. Diffuse reflectance spectroscopy (DRS) revealed a charge transfer band between O2− and Ho3+ ions in the range of 250–350 nm, supported by photoluminescence excitation (PLE) spectra. A bandgap of 3.39 eV was found for Ho3+-doped CaTiO3. At 0.03 mol Ho3+, the PLE band intensity was saturated, indicating optimal excitation efficiency. Emission spectra revealed distinct intra 4f–4f transitions, particularly a green emission at 545 nm under 454 nm excitation corresponding to 5F4 + 5S2 → 5I8 transition. The PL intensity reached its peak at 0.03 mol Ho3+ and then decreased due to concentration quenching. Color purity reached ~90%, highlighting its potential in applications requiring precise green emission. The results of the study suggest that this perovskite is well suited for optoelectronics, lighting, displays, or industries that require specific green light emission properties. [ABSTRACT FROM AUTHOR]

[Display omitted] Developing effective photocatalysts to achieve stable and efficient solar-induced hydrogen production remains a significant challenge due to rapid photocarrier recombination and sluggish hydrogen evolution kinetics. Here, a multi-interfacial engineering strategy involving the decoration of metallic Ni 3 C onto CaTiO 3 /Mn 0.5 Cd 0.5 S was proposed to create an S-scheme/Schottky hybrid heterostructure with multiple carrier transport paths for effective photocatalytic H 2 production. Exploiting the synergy between S-scheme heterojunction and Schottky barrier, the engineered ternary CaTiO 3 /Mn 0.5 Cd 0.5 S/Ni 3 C hybrid heterojunction exhibits outstanding photostability and significantly enhanced hydrogen evolution activity of 79.1 mmol g-1 h−1, which was about 4.55, 3.22 and 2.59 times greater than Mn 0.5 Cd 0.5 S, Mn 0.5 Cd 0.5 S/Ni 3 C, and CaTiO 3 /Mn 0.5 Cd 0.5 S, respectively. By creating an S-scheme heterojunction between CaTiO 3 and Mn 0.5 Cd 0.5 S, accompanied by a robust internal electric field (IEF), spatial charge separation can be effectively accelerated while ensuring the simultaneous preservation of highly active electrons and holes. Meanwhile, Ni 3 C nanoparticles, acting as a Schottky-junction H 2 generation cocatalyst, can efficiently trap the photoinduced electrons to establish multiple charge transfer channels and supply ample active sites for photoreduction reaction, thereby further optimizing the hydrogen generation kinetics. The integration of a Schottky barrier and S-scheme heterojunction in this research is expected to offer new perspectives for designing other highly effective hybrid catalysts for solar-to-hydrogen fuel conversion. [ABSTRACT FROM AUTHOR]

Novel and economic supports were prepared to facilitate the NiO‐reducibility and enrich the hydrogen production from the catalytic conversion of methane. Mixed (CaTi)‐oxides of CaO %=10, 20, and 30 were synthesized by direct compositing of CaCO3 and one‐pot synthesized (TiO2)‐nanoparticles. The developed nanostructures were characterized by a high‐resolution transmission electron microscope, X‐ray diffraction (XRD), temperature programmed reduction (TPR), and N2 adsorption‐desorption measurements. Practically, (Ni@30 % CaTiO3) the catalyst of cubic morphology, achieved a high hydrogen production ratio of 62.2 %. The incorporation of CaO to TiO2 hindered the formation of NiTiO3@NiCaTiO3 phases and facilitated the fast reduction of NiO‐phase to Ni (as revealed by temperature programmed reduction (TPR) and XRD. The formation of well‐ordered carbon nanotubes (CNTs) as valuable by‐products was also possible by these nanocomposites. The developed catalysts exhibited remarkable catalytic and structural stabilities. These results reflect the effective use of abundant CaO inorganic salt to enrich the H2 production by (CaTiO3) supports for potential and green energy production. [ABSTRACT FROM AUTHOR]

The present study used polyphenylene ether/Polypropylene/glass fiber (PPO/PP/GF) composites as the matrix material to obtain the dielectric plate material to be used in the dielectric phase shifters for 5G base stations. First, the reinforcement effect of the compound compatibilizers comprising PP‐g‐MAH and SEBS‐g‐MAH on the PPO/PP/GF composites was investigated. The experimental results revealed that the compound compatibilizers could dramatically improve the compatibility and performance of the PP/PPO/GF composites through synergistic compatibility. Next, the crystallization effect of CaTiO3 fillers on the PPO/PP/GF composites was investigated. The DSC analysis revealed that using a small amount of CaTiO3 promoted the crystallization of PP, while using a large amount of CaTiO3 inhibited the crystallization effect. At a compatibilizer content of 6 wt% and CaTiO3 in the range of 10–85 wt%, the CaTiO3/PP/PPO/GF composite presented a continuously adjustable dielectric constant (εr = 2.32–20.9), low dielectric loss (tanδ < 0.0019), and high heat resistance (VST = 169.5–177°C), and could, therefore, be used as a dielectric plate material in the dielectric phase shifters for 5G base stations. Highlights: The compound compatibilizers comprising PP‐g‐MAH and SEBS‐g‐MAH could dramatically improve the compatibility and performance of the PP/PPO/GF composites through synergistic compatibility.A small amount of CaTiO3 promoted the crystallization of PP and a large amount of CaTiO3 inhibited the crystallization effect.The CaTiO3/PP/PPO/GF composites could serve as ideal dielectric plate materials in the development of dielectric phase shifters for 5G base stations. [ABSTRACT FROM AUTHOR]

Herein, we reported the construction of hydrogen peroxide (H2O2) sensor using calcium titanate modified screen printed electrode (CaTiO3@SPE). The CaTiO3 has been synthesized via hydrothermal method using calcium nitrate tetrahydrate and titanium butoxide as the Ca and Ti source. The CaTiO3 was characterized by many physiochemical techniques such as powder X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), Brunauer–Emmett–Teller (BET) and scanning electron microscopy (SEM). The XRD analysis revealed the existence of decent crystalline nature in the synthesized material, while EDX results demonstrated its good phase purity. The SEM micrographs suggested that CaTiO3 has flakes-like surface structure. The BET results also indicated that CaTiO3 has specific surface area of 57.6 m2/g. Furthermore, CaTiO3 was used as the electrode material and CaTiO3@SPE has been constructed using drop-casting method. The fabricated CaTiO3@SPE was used for the sensing of H2O2 using cyclic voltammetry and linear sweep voltammetry methods. The CaTiO3@SPE exhibited reasonable limit of detection of 0.08 µM with good selectivity, stability and repeatability. [ABSTRACT FROM AUTHOR]

As the parent compound of the perovskite-structured family and an analogue of davemaoite CaSiO3 in Earth's lower mantle, CaTiO3 perovskite is widely used in electronic ceramic materials, immobilizing radioactive waste, and geosciences. Here we report the discovery of a natural pure CaTiO3 perovskite-C in calc-silicate veins in brucite marble in the Tazheran Massif, Russia. The mean composition of perovskite-C is 97 wt% total CaO and TiO2, and minor impurities of Na, Al, and Zr, yielding the chemical formula CaTi0.97Al0.01Na0.01Zr0.01O3. The cubic crystal structure--Pm3m, Z = 1: a = 3.8301 Å, V = 56.19 (2) Å3 (ρ = 4.019 g/cm3) has been refined to R1 = 0.0451. Compared with the cubic perovskite discovered in Israel, the cubic perovskite discovered in this study is very pure in Ca and Ti. The naturally occurring perovskite-C from Tazheran implies that the host skarn might have experienced high-temperature (> 1247--1374 °C) metamorphism and/or metasomatism at an early stage. Moreover, the discovery of natural perovskite-C also draws attention to considering crystal-structure- related matrix effects in the future of in situ U-Pb geochronology, especially using Tazh international perovskite standards. [ABSTRACT FROM AUTHOR]

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Los contaminantes orgánicos son altamente tóxicos y volátiles se acumulan en los tejidos grasos; Debido a su persistencia y movilidad, es posible encontrarlas prácticamente en cualquier parte del planeta, incluso en lugares donde nunca han sido utilizadas. Por esta razón, el monitoreo y la vigilancia en los cuerpos de agua son fundamentales. En la presente investigación, se sintetizaron partículas de titanato de calcio (CaTiO3) utilizando el método de estado sólido. Las partículas se caracterizaron por diversas técnicas fisicoquímicas: difracción de rayos-X (DRX), espectroscopia Raman, microscopía electrónica de barrido (MEB), espectroscopia de dispersión de energía (EDE), espectroscopia de reflectancia difusa (ERD), y electroquímica: voltamperometría cíclica (VC), entre otras. Se encontró a través de DRX y Raman que la estructura cristalina es ortorrómbica con el grupo espacial Pbnm. Las partículas de CaTiO3 sintetizadas tienen un diámetro promedio de ≈ 2 µm; Además, el valor obtenido para la brecha de energía (Eg) fue de 3,41 eV; también presenta un paso de baja energía en un valor de 2.66 eV, que puede corresponder a los estados electrónicos mingap. El electrodo de carbón vítreo modificado con la película de CaTiO3 mostro una sensibilidad para la determinación de nitrobenceno (NB) en solución acuosa. Por lo tanto, se puede concluir que el desarrollo de partículas de CaTiO3 es una alternativa viable para ser utilizado como sensor de contaminantes orgánicos en agua.

Cation-anion co-doping has proven to be an effective method of improving the photocatalytic performances of CaTiO3 perovskites. In this regard, (La/Ce-N/S) co-doped CaTiO3 models were investigated for the first time using first-principles calculations based on a supercell of 2 × 2 × 2 with La/Ce concentrations of 0.125, 0.25, and 0.375. The energy band structure, density of states, charge differential density, electron-hole effective masses, optical properties, and the water redox potential were calculated for various models. According to our results, (La-S)-doped CaTiO3 with a doping ratio of 0.25 (LCOS1-0.25) has superior photocatalytic hydrolysis properties due to the synergistic performances of its narrow band gap, fast carrier mobility, and superb ability to absorb visible light. Apart from the reduction of the band gap, the introduction of intermediate energy levels by La and Ce within the band gap also facilitates the transition of excited electrons from valence to the conduction band. Our calculations and findings provide theoretical insights and solid predictions for discovering CaTiO3 perovskites with excellent photocatalysis performances. [ABSTRACT FROM AUTHOR]

Yttrium oxide (Y 2 O 3) is widely used in titanium (Ti) alloy casting for its low activity, strength, and heat resistance. Wax mold and ceramic coating preparation in traditional investment casting is cumbersome; hence, this work proposes extrusion-based 3D printing of Y 2 O 3 -based ceramic shells. This study investigates how trace CaTiO 3 affects sintering performance, showing that small amounts can reduce sintering temperature and significantly increase bending strength. Adding 2 mol% CaTiO 3 increased the bending strength from 4.3 to 43.1 MPa after sintering at 1500 °C, while not wetting with the Ti–6Al–4V titanium alloy. This method offers a promising way to produce high-performance Y 2 O 3 -based ceramic shells with lower sintering temperatures. [ABSTRACT FROM AUTHOR]

Perovskites have been pointed out as promising candidates for several technologic areas, especially for photovoltaic applications. In this work, CaTiO3 compounds were synthesized by using the Pechini method and their structural, optical, and electrical properties were investigated. Tilted octahedral oxygen arrangements with a single center of symmetry for positive and negative electric charges are observed, forming a nonpolar perovskite structure. The origin of the observed structural distortions is directly linked to the strongest chemical bond between the O1−2 and Ti+4 ions. Direct (2.9 eV) and indirect (3.8 eV) optical band gaps are also observed. [ABSTRACT FROM AUTHOR]

The extraction of titanium-bearing components in the form of CaTiO3 is an efficient utilization of blast furnace slag. The photocatalytic performance of this obtained CaTiO3 (MM-CaTiO3) as a catalyst for methylene blue (MB) degradation was evaluated in this study. The analyses indicated that the MM-CaTiO3 had a completed structure with a special length–diameter ratio. Furthermore, the oxygen vacancy was easier to generate on a MM-CaTiO3(110) plane during the photocatalytic process, contributing to improving photocatalytic activity. Compared with traditional catalysts, MM-CaTiO3 has a narrower optical band gap and visible-light responsive performance. The degradation experiments further confirmed that the photocatalytic degradation efficiency of pollutants by using MM-CaTiO3 was 3.2 times that of pristine CaTiO3 in optimized conditions. Combined with molecular simulation, the degradation mechanism clarified that acridine of MB molecular was stepwise destroyed by using MM-CaTiO3 in short times, which is different from demethylation and methylenedioxy ring degradation by using TiO2. This study provided a promising routine for using solid waste to obtain catalysts with excellent photocatalytic activity and was found to be in keeping with sustainable environmental development. [ABSTRACT FROM AUTHOR]

The actual pulse capacitor application of BiFeO 3 -based relaxor ferroelectric ceramics has been greatly hindered by low dielectric breakdown strength and poor thermal stability. In this work, these issues are solved by manufacturing nanodomain-engineered and grain-engineered BiFeO 3 -BaTiO 3 -CaTiO 3 relaxor ferroelectric ceramics. The introduction of CaTiO 3 induces nanoscale domains in the ferroelectric BiFeO 3 -BaTiO 3 matrix, bringing about temperature-insensitive dielectric response and almost hysteresis-free polarization field response. Furthermore, largely enhanced dielectric breakdown strengths are also achieved, which is mainly attributed to the refinement of the grain size and the depression of the oxygen vacancy concentration. Consequently, remarkable energy-storage performances with high recoverable energy density (W rec ∼ 5.03 J/cm3), high efficiency (η ∼ 89.7%), and outstanding thermal stability (W rec variation < 4% from 30 to 150 ℃) are obtained. Moreover, ultrafast release time (t 0.9 ∼ 65 ns) and high power density (∼75.14 MW/cm3) are also achieved, proving the BiFeO 3 -BaTiO 3 -CaTiO 3 ceramics' enormous potential for underlying advanced pulse capacitor applications. [ABSTRACT FROM AUTHOR]

Nanoflower-like MoS2 deposited on the surface of rectangular CaTiO3(CTO) was designed and synthesized via a simple template-free strategy. Through SEM, TEM, and other characterization methods, the MoS2 nanoflowers were confirmed to be well deposited on the surface of CTO. LED was used as the visible light source, and rhodamine B (RhB) in an aqueous solution was used as the model pollutant to assess the photodegradation activity of the samples. The results showed that the MoS2/CaTiO3(MCTO) composite significantly improved the photocatalytic degradation of rhodamine B (RhB) in water, compared with a single CTO, and with the MCTO-2 composite photocatalysts, 97% degradation of RhB was achieved in 180 min, and its photocatalytic activity was about 5.17 times higher than that of the bare CTO. The main reasons for enhancing photocatalytic performance are the strong interaction between the nanoflower-like MoS2 and rectangular CTO, which can lead to the effective separation of electron transfer and photoexcited electron–hole pairs in MCTO composites. This work provides a new notion for researching an effective method of recycling catalytic materials. [ABSTRACT FROM AUTHOR]

This research is devoted to studying the radiation-protecting characteristics of calcium titanate (CaTiO3) perovskite-based ceramic material. The ceramics were made by the solid-state reaction method (SSRM) and treated at temperatures of 1300 °C, 1200 °C, and 1100 °C. The structural characteristics of the ceramics were analyzed by XRD and FT-IR. The results indicated a CaTiO3 phase formation with an orthorhombic structure. The size of the crystallites was in the range of 27–36 nm and was found to increase as the temperatures increased. The relative density showed an increase from 93% to 96% as the temperatures varied from 1100 °C to 1300 °C. The impact of temperature on the radiation-protecting characteristics of the CaTiO3 ceramic was assessed using the Monte Carlo simulation (MCS). There was a slight decrease in the γ-photons average track length with a raising of the temperature. At a γ-photon energy of 0.662 MeV, the γ-photons' average track lengths diminished from 3.52 cm to 3.38 cm by raising the temperature from 1100 °C to 1300 °C. The illustrated decrease in the γ-photons average track length affected the linear attenuation coefficient (µ) where the µ increased from 0.28 to 0.30 cm−1 with a rising temperature from 1100 °C to 1300 °C. [ABSTRACT FROM AUTHOR]

This research investigates the potential of Calcium titanate (CaTiO 3 or CT) nanoparticles as functional additives to enhance the dielectric properties of Barium titanate (BaTiO 3 or BT)-based ceramic dielectrics. To address the need for high-temperature stability in MLCC (multilayer ceramic capacitor) applications, especially within the automotive and aerospace sectors, we have explored BT-based complex perovskite solid solutions comprising various cation substitutions, including Ca2+ and Yb3+, into barium titanate (BT) as a method to suppress the dielectric property anomaly near the Curie temperature effectively. The focus is on the impact of the application of CT nanoparticles as additive materials on phase formation, microstructure development, and dielectric behavior of the resulting ceramics to align with the Extended 'Temperature Coefficient of Capacitance (TCC)' criteria defined by the EIA X8R specification. When the hydrothermally synthesized CT nanopowder was applied in the Ca-doped BT ceramics fabrications as source material of the Ca dopants, it was beneficial to achieve both temperature stability and high dielectric constant. The CT nanoparticles are believed to play multiple roles during the solid-state reaction with BT and rare earth dopant (Yb). Since the Yb3+ ions can be more easily dissolved into the CT lattice than BT with their amphoteric character, the CT nanoparticles in the BT-CT-Yb 2 O 3 mixture can act as an intermediary, dissolving the Yb3+ first in its A- or B-site before the final solid-solution formation with the BT. The sequential substitutions of the Yb3+ and Ca2+ into BT via CT nanoparticles could affect the site occupancy of Ca2+ in the BT lattice, which is very important in determining the dielectric properties of the Ca-doped BT processed in reducing atmospheres. Through a comprehensive experimental approach, including phase composition analysis via X-ray diffraction (XRD) and microstructural examination using Field Emission Scanning Electron Microscopy (FE-SEM) and Transmission Electron Microscopy (TEM), this work reveals the significance of synthetic methodology and dopant incorporation strategy on achieving a desired core-shell microstructure and improved dielectric performance. This research underscores the efficacy of CT nanoparticles as a promising route towards the development of BT-based dielectric ceramics with superior temperature stability, offering valuable insights for the advancement of MLCC technology to cater to high-temperature applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ethanol-quenching introduces both surface oxygen vacancies (V O s) and bulk single electron trapped oxygen vacancies (SETOVs) to CaTiO 3. • The band gap is narrowed and the visible light absorption ability is enhanced after quenching. • The photocatalytic RhB degradation and hydrogen evolution reaction are significantly promoted on the ethanol-quenched Q E -CaTiO 3. • DFT calculations verify the narrowed band gap and the accumulated electrons near the Fermi level. Oxygen vacancies (V O s) play a pivotal role in promoting the photocatalytic activities of perovskite oxides. Herein, we proposed a simple and effective strategy of introducing both surface oxygen vacancies and bulk single electron trapped oxygen vacancies (SETOVs) into CaTiO 3 by ethanol quenching. The purchased CaTiO 3 was preheated at 800 °C and then the hot CaTiO 3 was quenched in ethanol instantly. The ethanol-quenched Q E -CaTiO 3 delivers much improved photocatalytic activities towards both RhB degradation and hydrogen evolution under visible light irradiation by 6.5 and 65.2 times, respectively, in comparison with the pristine CaTiO 3. Both the bulk SETOVs and surface V O s enhance light absorption, and the surface V O s serve as photocatalytic active sites. DFT calculations further reveal the narrowed band gap and accumulated charge density near the Fermi level in Q E -CaTiO 3 , which help the visible light absorption, facilitate charge carriers generation and migration, and promote photocatalytic activities. Our findings provide an efficient and easily scalable approach to engineering oxygen vacancy defects in photocatalysts and other catalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel heterojunction consisting of multishelled hollow CaTiO 3 cubes and Co 0.2 Cd 0.8 S nanoparticles was designed. • An S-scheme charge transfer route within the heterojunction was confirmed. • Mechanism for the enhanced photoactivity over Co 0.2 Cd 0.8 S/CaTiO 3 heterojunction discussed. • High H 2 -production rate achieved over heterojunction, 3.58-fold higher than Co 0.2 Cd 0.8 S. Rationally designing S-scheme heterostructures with boosted charge separation efficiency and superior redox ability is regarded as an appealing strategy to conquer the shortcomings of mono-component and conventional heterojunction photocatalysts. Herein, a novel hierarchical S-scheme heterostructured photocatalyst was constructed by integrating Co 0.2 Cd 0.8 S nanoparticles on multishelled hollow CaTiO 3 cubes to substantially improve the photocatalytic hydrogen production activity. An internal electric field (IEF) is formed at the heterojunction interfaces owing to the significant disparity in Fermi level (E F) between Co 0.2 Cd 0.8 S and CaTiO 3 , accompanied by the energy band bending, which enables the S-scheme charge transport route in the Co 0.2 Cd 0.8 S/CaTiO 3 heterostructure, as verified by electron paramagnetic resonance and theoretical calculations. Benefiting from the boosted separation efficiency and superior redox capability of photocarriers within the constructed S-scheme heterostructure, the optimized Co 0.2 Cd 0.8 S/CaTiO 3 sample exhibited a significantly improved photocatalytic hydrogen evolution rate of 8.13 mmol h−1 g−1, far exceeding that of mono-component counterparts and previously reported Co 0.2 Cd 0.8 S- or CaTiO 3 -based photocatalysts. This study is anticipated to inspire the strategic development of other economical and efficient S-scheme photocatalytic systems with enhanced H 2 evolution activity. [ABSTRACT FROM AUTHOR]

Cation-anion co-doping has proven to be an effective method of improving the photocatalytic performances of CaTiO3 perovskites. In this regard, (La/Ce-N/S) co-doped CaTiO3 models were investigated for the first time using first-principles calculations based on a supercell of 2 × 2 × 2 with La/Ce concentrations of 0.125, 0.25, and 0.375. The energy band structure, density of states, charge differential density, electron-hole effective masses, optical properties, and the water redox potential were calculated for various models. According to our results, (La-S)-doped CaTiO3 with a doping ratio of 0.25 (LCOS1-0.25) has superior photocatalytic hydrolysis properties due to the synergistic performances of its narrow band gap, fast carrier mobility, and superb ability to absorb visible light. Apart from the reduction of the band gap, the introduction of intermediate energy levels by La and Ce within the band gap also facilitates the transition of excited electrons from valence to the conduction band. Our calculations and findings provide theoretical insights and solid predictions for discovering CaTiO3 perovskites with excellent photocatalysis performances.

Near-infrared (NIR) persistent luminescence (PersL) materials have unique optical properties with promising applications in bioimaging and anticounterfeiting. However, their development is currently hindered by poor red-light-exciting ability. In this study, CaTiO 3 :Cr 0.001 ,Y 0.02 (CTCY) was synthesized with 650 nm-excited 772 nm NIR PersL. The Y 3+ doping in the Ca 2+ lattice plays a key role in the PersL property. A charge compensation mechanism was proposed, in which Cr 3+ in the Ti 4+ lattice was stabilized by Y 3+ -doping while oxygen vacancies were generated to store the excitation energy at the same time. A thermal ionization mechanism might elucidate the red-light-excited NIR PersL of CTCY, which benefits from the perovskite structure of CaTiO 3 . CTCY has 120 times more intense red-light-excited PersL than Zn 3 Ga 2 Ge 2 O 10 :Cr. Its potential applications in luminescence anticounterfeiting and bioimaging were demonstrated using a visible/NIR dual-channel PersL flower painting and a CTCY-labeled bone screw for in situ reactivable PersL imaging using red light illumination instead of X-ray, respectively. This study not only provides a new NIR PersL material but also will add to our understanding in developing other potential red-light- or even NIR-activable PersL materials with perovskite-like structures.

Herein, titanate-based perovskite CaTiO 3 nanosheets were successfully designed via boron nitride quantum dots (BNQDs) to fabricate CaTiO 3 /BNQDs catalyst. The as-fabricated composite catalysts were analysed by transmission electron microscope (TEM), scanning electron microscopy coupled with energy dispersive spectrometry (SEM-EDS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR), X-ray diffraction (XRD), UV–vis spectroscopy (UV-DRS), photoluminescence (PL) and electrochemical impedance spectroscopy (EIS) techniques. SEM-Mapping analysis showed that the boron and nitrogen elements dispersed well over the CaTiO 3 surface which was useful for building electronic channels for rapid transport of photo-induced charge pairs. TEM images verified the attachment of BNQDs around the surface of host CaTiO 3 forming intimate interface while the distribution of chemical states was observed by XPS analysis demonstrating strong coupling effect between BNQDs and CaTiO 3 through Ti–O–N and Ti–O–B bonds. Moreover, PL and light absorption properties enhanced with the quantum confinement effect of BNQDs. As expected, the photocatalytic degradation rate of CaTiO 3 /BNQDs was increased to k app = 0.015 min− 1 with optimum BNQDs loading, which was 2.31 times folder than that of bare CaTiO 3 (0.006 min− 1). The enhanced photocatalytic efficiency was observed for CaTiO 3 /BNQDs than pristine perovskite on account of formation of electron tapping sites, decreased band gap energy and hindered recombination rate. On the other hand, in the presence of H 2 O 2 , the degradation percentage increased from 88.5% to 92.1% at the end of 120 min of irradiation while 96.8% of TC was quickly degraded within 60 min after activating with peroxymonosulfate which created strong sulphate radicals. Radical trapping tests indicated that the photo-generated holes were the primary active species in the photocatalytic mechanism. Moreover, CaTiO 3 /BNQDs catalyst showed excellent stability in recycling tests. Besides, the possible degradation mechanism was proposed. This study shed light on the significance of BNQDs in the enhancement of the photocatalytic activities of titanate-based perovskite for effective degradation of tetracycline antibiotic in contaminated water. [Display omitted] [ABSTRACT FROM AUTHOR]

(1- x) (0.98Na 0.5 Bi 0.5 TiO 3 –0.01BaTiO 3 –0.01BiFeO 3)– x CaTiO 3 (NBB- x CT) ceramics were produced using traditional solid-state synthesis methods. The surface morphology, domain structure, and electrical properties of the ceramic samples were systematically studied. In addition, the temperature and frequency stabilities of the NBB-15CT sample at 200 kV/cm were tested. Generally, NBB- x CT ceramics exhibit a typical single perovskite phase structure. The results indicate that the NBB-15CT ceramics showed a high energy density of 3.14 J/cm3 at 250 kV/cm. The piezoresponse force microscopy (PFM) results showed that the addition of CT broke the macrodomains of the 0.98Na 0.5 Bi 0.5 TiO 3 -0.01BaTiO 3 -0.01BiFeO 3 ceramic and helped to form nanodomains, leading to an improved energy storage performance. The above performance indicates that the specimens possess very good temperature-and frequency-dependent energy storage performances at 30–150 °C and 1–100 Hz. Moreover, the electric energy storage and release in the NBB-15CT ceramic indicated that the power density could reach 55.30 MV/cm3 at 180 kV/cm. Therefore, the NBB-15CT ceramic is a promising material for electrical capacitors. [ABSTRACT FROM AUTHOR]

The Ca-rich and Sr-rich stoichiometric and non-stoichiometric materials were obtained by the modified citrate method. After calcination at 900 °C, materials were characterized in terms of structure, microstructure and reducibility in an H 2 -containing atmosphere. The diffractometric data did not confirm the presence of Co-originated phases. Co K-edge and Ti K-edge were recorded and analyzed for a deeper description of the structural properties of materials, mainly the influence of non-stoichiometry on the effectiveness of Co incorporation into the perovskite systems. The X-ray absorption near edge structure study combined with temperature programmed reduction results indicated the presence of CoTiO 3 and cobalt oxides phases for Ca-rich and Sr-rich. This approach also allowed to observe that non-stoichiometry in Sr-rich materials results in a lower amount of cobalt incorporated into the perovskite structure and a higher amount of Co 3 O 4 formed. Additionally, for Ca-rich materials, XANES spectra indicated a higher amount of Co in the Ti sublattice and confirmed the higher Co2+/Co3+ ratio than in the case of Sr-rich materials. [Display omitted] • Synthesis of Co-modified CaTiO 3 –SrTiO 3 materials by modified citrate method. • The impact of perovskite structure symmetry on cobalt incorporation. • A higher Co2+/Co3+ ratio for Ca-rich materials. • The effect non-stoichiometry on Co incorporation and the formation of Co-rich phases. [ABSTRACT FROM AUTHOR]

• Green chemistry approach of CaTiO 3 phase from Pensi shell waste is proposed. • Single-phase CaTiO 3 phase is obtained and adopts a PBNM orthorhombic structure. • The ferroelectric ordering is induced by the distortion of TiO 6 octahedra. • CaTiO 3 ceramic exhibits energy storage efficiency of 84.8 %. Recently, dielectric capacitors have attracted immense interest as energy storage materials. In this work, we prepare the dielectric material CaTiO 3 by the molten-salt method, utilizing Pensi shell waste as a natural calcium source, aligning with principles of green chemistry. Pensi shell contains 53.1 % calcium oxide, as revealed by TGA analysis, suggesting its potential use as a natural precursor in CaTiO 3 synthesis. The phase formation, structure, and electrical properties of the resulting CaTiO 3 phase are investigated. XRD data revealed the formation of single-phase CaTiO 3 and a distortion of the TiO 6 octahedra, accompanied by displacement of the A -site cations resulting in an orthorhombic Pbnm structure. CaTiO 3 exhibits good linear dielectric characteristics with an energy storage efficiency of 84.8 %. [Display omitted] [ABSTRACT FROM AUTHOR]

The extraction of titanium-bearing components in the form of CaTiO3 is an efficient utilization of blast furnace slag. The photocatalytic performance of this obtained CaTiO3 (MM-CaTiO3) as a catalyst for methylene blue (MB) degradation was evaluated in this study. The analyses indicated that the MM-CaTiO3 had a completed structure with a special length–diameter ratio. Furthermore, the oxygen vacancy was easier to generate on a MM-CaTiO3(110) plane during the photocatalytic process, contributing to improving photocatalytic activity. Compared with traditional catalysts, MM-CaTiO3 has a narrower optical band gap and visible-light responsive performance. The degradation experiments further confirmed that the photocatalytic degradation efficiency of pollutants by using MM-CaTiO3 was 3.2 times that of pristine CaTiO3 in optimized conditions. Combined with molecular simulation, the degradation mechanism clarified that acridine of MB molecular was stepwise destroyed by using MM-CaTiO3 in short times, which is different from demethylation and methylenedioxy ring degradation by using TiO2. This study provided a promising routine for using solid waste to obtain catalysts with excellent photocatalytic activity and was found to be in keeping with sustainable environmental development.

Structural, Microstructure and RL curves of Single and Double Layers Absorbers of D and D/M samples. [Display omitted] Herein, two distinct nanocomposites of CaTiO 3 micro-cubes and polygonal SrFe 12 O 19 , both decorated with NiO nanoparticles, were successfully synthesized using hydrothermal method. The physico-chemical features of as-prepared samples were evaluated via XRD, FTIR, UV–vis, BET, XPS, FESEM and EDS analysis. Microwave attenuation features of as-prepared single layer absorbers were determined by VNA analysis in 2–18 GHz. Simulation confirmation was checked by preparing a bi-layer samples and evaluating it using VNA analysis after finding the appropriate thickness of each layer. The reflection loss from each single layer samples containing 20 wt% of each CaTiO 3 /NiO and SrFe 12 O 19 /NiO nanocomposites were −16 dB and −35 dB at 6.3 GHz with 2.5 mm matching thickness respectively. However, the RL was −34 dB at 10 GHz frequency with 2 mm thickness in a bilayer absorber with SrFe 12 O 19 /NiO nanocomposite layer put as absorbing layer with 1 mm thickness and CaTiO 3 /NiO positioned as matching layer with 1 mm thickness. Furthermore, at the X-band frequency, approximately entire band absorption is obtained. The findings demonstrate that adjusting the order and thickness of the layers in a bilayer absorber may readily improve microwave absorption performance. By comparing the results of simulation with real prepared bilayer absorbers, we found that with a 2 mm overall thickness, the bi-layer absorbers display accurate RL values, but not the matching frequency monitored in the simulation process. In reality, this discrepancy was unavoidable. [ABSTRACT FROM AUTHOR]

Due to the balance of dielectric and magnetic losses achieved by impedance matching, combining dielectric and magnetic materials might result in potential microwave absorbers. However, some dielectric/ferromagnetic materials could also be used as good microwave absorbers, such as CaTiO 3. In order to improve the microwave absorption features of CaTiO 3 , we fabricated two CaTiO 3 -based composites as CT/C (CaTiO 3 /Cu) and CT/C/B (CT/C/hexagonal boron nitride, h -BN). By decorating h -BN, the CT/C/B achieved a large specific area and a high total pore volume, which was beneficial to the microwave absorption performance in f = 8.2–12.4 GHz of CT/C/B compared to that of CT/C. The reflection loss (RL) was reasonably good as −15 dB for CT/C composite, while CT/C/B could reach the RL of −40 dB. Better microwave absorption dissipation features of CT/C/B compared to CT/C could result from higher electrical conductivity, attenuation constant, and lower skin depth. The presence of h -BN in the composite could also tune the total shielding effectiveness of CT/C/B to 32.5 dB, which was equal to 1.4 times compared to that of CT/C (23.5 dB). [ABSTRACT FROM AUTHOR]

The utilization of titanium-bearing blast furnace slag (TBFS) has been widely concerned, which is mainly related to the recovery of titanium resources. In order to realize the efficient and clean recovery of titanium resource, the main titanium-bearing phases (CaTiO 3 , MgTiO 3 and Mg 2 TiO 4) in TBFS with high content of MgO were investigated in CH 4 –H 2 system in this work. Thermodynamic calculation indicated that CaTiO 3 , MgTiO 3 and MgTi 2 O 4 could be ultimately reduced to TiC x O y at 1300 °C, 1200 °C and 1200 °C respectively. The reduction experiments were carried out in flowing CH 4 –H 2 , which considered the influences of time, temperature and addition, the results of which showed that the optimal reduction temperatures of CaTiO 3 and MgTiO 3 were 1400 °C and 1200 °C respectively. DFT calculation results also confirmed that MgTiO 3 had stronger CH 4 adsorption capacity than CaTiO 3 and Mg 2 TiO 4. However, Mg 2 TiO 4 could not be reduced completely even at 1450 °C, because excessive MgO in the reduced products prevented further reaction in kinetics. Both increasing temperature and adding iron oxides contributed to the reduction kinetics. The results suggested that the appropriate increase of the proportion of MgO in TBFS was beneficial to titanium extraction. This work provides a way to develop new process to extract titanium from TBFS, especially the slag with high MgO. [Display omitted] • A novel method to reduce and carbonize CaTiO 3 , MgTiO 3 and Mg 2 TiO 4 was proposed. • Thermodynamic and experimental study on the reduction by CH 4 –H 2 was performed. • The reduction mechanism of gas-solid reaction with CH 4 –H 2 was discussed. • The DFT-calculated adsorption energy (E ads) for CH 4 and H 2 adsorption was carried. [ABSTRACT FROM AUTHOR]

Nanoflower-like MoS2 deposited on the surface of rectangular CaTiO3(CTO) was designed and synthesized via a simple template-free strategy. Through SEM, TEM, and other characterization methods, the MoS2 nanoflowers were confirmed to be well deposited on the surface of CTO. LED was used as the visible light source, and rhodamine B (RhB) in an aqueous solution was used as the model pollutant to assess the photodegradation activity of the samples. The results showed that the MoS2/CaTiO3(MCTO) composite significantly improved the photocatalytic degradation of rhodamine B (RhB) in water, compared with a single CTO, and with the MCTO-2 composite photocatalysts, 97% degradation of RhB was achieved in 180 min, and its photocatalytic activity was about 5.17 times higher than that of the bare CTO. The main reasons for enhancing photocatalytic performance are the strong interaction between the nanoflower-like MoS2 and rectangular CTO, which can lead to the effective separation of electron transfer and photoexcited electron–hole pairs in MCTO composites. This work provides a new notion for researching an effective method of recycling catalytic materials.

This research is devoted to studying the radiation-protecting characteristics of calcium titanate (CaTiO3) perovskite-based ceramic material. The ceramics were made by the solid-state reaction method (SSRM) and treated at temperatures of 1300 °C, 1200 °C, and 1100 °C. The structural characteristics of the ceramics were analyzed by XRD and FT-IR. The results indicated a CaTiO3 phase formation with an orthorhombic structure. The size of the crystallites was in the range of 27–36 nm and was found to increase as the temperatures increased. The relative density showed an increase from 93% to 96% as the temperatures varied from 1100 °C to 1300 °C. The impact of temperature on the radiation-protecting characteristics of the CaTiO3 ceramic was assessed using the Monte Carlo simulation (MCS). There was a slight decrease in the γ-photons average track length with a raising of the temperature. At a γ-photon energy of 0.662 MeV, the γ-photons’ average track lengths diminished from 3.52 cm to 3.38 cm by raising the temperature from 1100 °C to 1300 °C. The illustrated decrease in the γ-photons average track length affected the linear attenuation coefficient (µ) where the µ increased from 0.28 to 0.30 cm−1 with a rising temperature from 1100 °C to 1300 °C.

La(OH)3/CaTiO3 composite photocatalyst with a heterjunction structure was synthesized by a facile method of solvothermal procedure. La(OH)3 was dispersed on the surface of CaTiO3 with butterfly-like dendrites. The photocatalytic activity of La(OH)3/CaTiO3 heterostructure was enhanced for methylene blue (MB) degradation under ultraviolet (UV) irradiation. Especially 7La(OH)3/CaTiO3 obtained a highest MB degradation of 95.9%, which is 1.33 times higher than that of pure CaTiO3. The trapping experiment suggested that •OH active radical plays the major role. The enhanced photocatalytic activity over 7La(OH)3/CaTiO3 heterostructure on the degradation of MB is attributed to the butterfly-like dendrites CaTiO3 and the effectively separation of charged carriers. [ABSTRACT FROM AUTHOR]

In this paper, series of perovskites ceramics (CaTiO3, BaTiO3–SrTiO3) added with 1.0 wt.% of tin oxide SnO2 were fabricated through the solid-state reaction process. The different specimens' structural and functional groups examinations were investigated by using X-ray and Fourier transform infrared spectrophotometer (FTIR) techniques. The surface morphology and elemental composition were examined by scanning electron microscope (SEM) with energy dispersive X-ray analysis (EDX). The XRD peaks of CaTiO3 and BaTiO3–SrTiO3 were indexed to the orthorhombic and cubic perovskites, respectively. The inclusion of tin oxide into the prepared ceramics caused shifting in the position of the peaks towards higher angles resulting in deformation in the crystal structure of the ceramics. FTIR results confirmed the formation of the desired compositions. The average grain size increased upon the addition of ton oxide into CaTiO3 and BaTiO3–SrTiO3 ceramics. In addition, the radiation shielding performances were examined. The results showed that the addition of SnO2 to the CaTiO3 and BaTiO3–SrTiO3 ceramics enhances the shielding properties of these ceramics. The linear attenuation coefficient (LAC) at a gamma photon energy of 0.015 MeV enhanced from 72.186 to 73.115 cm−1 when the SnO2 increase from 0 to 1 wt.% for samples CTO and CTO@SnO2, respectively. In this regard, the LAC coefficient of BTO–STO is 168.813 cm−1, and it is enhanced by adding 1 wt.% of SnO2 to be 171.004 cm−1 for sample BTO–STO@SnO2. The results also illustrate a decrease in the ceramics half-value layer and the gamma-ray transmission factor with the addition of the SnO2 in the ceramic matrix. The results obtained validate the possibility of applying the manufactured ceramics for radiation protection purposes. [ABSTRACT FROM AUTHOR]

[Display omitted] Ternary ABX 3 perovskites made of corner-sharing BX 6 octahedra have long featured prominently in solid-state chemistry and condensed matter physics. Still, the joint understanding of their two main subgroups— halides and oxides —has not been fully developed. Indeed, unlike the case in simpler compounds having a single, robust repeated motif ("monomorphous"), certain cubic perovskites can manifest a non-thermal (= intrinsic) distribution of local motifs ("polymorphous networks"). Such static deformations can include positional degrees of freedom (e.g., atomic displacements and octahedral tilting) or magnetic moment degrees of freedom in paramagnets. Unlike thermal motion, such static distortions do not time-average to zero, being an expression of the intrinsic symmetry breaking preference of the chemical bonding. The present study compares electronic structure features of oxide and halide perovskites starting from the static polymorphous distribution of motifs described by Density Functional Theory (DFT) minimization of the internal energy, continuing to finite temperature thermal disorder modeled via finite temperature DFT molecular dynamics. We find that (i) different oxide vs. halide ABX 3 compounds adopt different energy-lowering symmetry-breaking modes. The calculated pair distribution function (PDF) of SrTiO 3 from the first-principles agrees with recently measured PDF. (ii) In both oxides and halides, such static distortions lead to band gap blueshifts with respect to undistorted cubic Pm -3 m structure. (iii) For oxide perovskites, high-temperature molecular dynamics simulations initiated from the statically distorted polymorphous structures reveal that the thermally-induced distortions can lead to a band gap redshift. (iv) In contrast, for cubic halide perovskite CsPbI 3 , both the intrinsic distortions and the thermal distortions contribute in tandem to band gap blueshift , the former, intrinsic effect being dominant. (v) In the oxide SrTiO 3 and CaTiO 3 (but not in halide) perovskites, octahedral tilting leads to the emergence of a distinct Γ–Γ direct band gap component as a secondary valley minimum to the well-known indirect R–Γ gap. Understanding such intrinsic vs. thermal effects on oxide vs. halide perovskites holds the potential for designing target electronic properties. [ABSTRACT FROM AUTHOR]

CaAl2O4:Eu2+, Nd3+ phosphor was synthesized by a solid-state method at 1400 °C. The CaAl2O4:Eu2+, Nd3+ phosphor particles were coated by sol–gel dip coating method with a peroxo treated titanium hydroxide complex solution. The effect of peroxo treatment time and calcination temperatures was investigated in comparison with conventional TiO2-sol coated nanocomposites. Characterization of the CaAl2O4:Eu2+, Nd3+/TiO2 nanocomposites was conducted by X-ray diffraction, scanning electron microscopy, UV–Vis absorption spectra, and energy dispersive spectroscopy. The photocatalytic reactivity was evaluated by degradation of methylene blue aqueous solution under ultra-violet and visible light irradiations. CaAl2O4:Eu2+, Nd3+/TiO2 composite coated with peroxo titanium complex solution for 80 s showed the fastest photocatalytic reactivity under ultra violet and visible light illumination. Peroxo treatment for a long soaking time of 300 s effected etching of the phosphor surface and formation of CaTiO3 phases. With prolongation of the time of soaking the phosphor in the peroxo titanium complex solution to 300 s, the photocatalytic reactivity of the CaAl2O4:Eu2+, Nd3+/TiO2 composite decreased. In addition, composites displayed excellent photocatalytic under visible light irradiation, compared with pure TiO2. The acidity of the peroxo treatment, soaking time, and heat treatment conditions are important parameters for synthesizing photoactive nanocomposites for pollution control application. CaAl2O4:Eu2+, Nd3+ was coated with peroxo treated TiO2-sol under different coating times. The peroxo treatment imparted acidic pH while longer soaking times resulted in etching of the phosphor surface. A wavy micro-ridge microstructure with dispersed clusters of TiO2 was dominant in the 300 s coated samples. The samples without peroxo treated (CTB) and 80 s coated samples were densely coated with TiO2 nanoparticles. The CaAl2O4:Eu2+, Nd3+/TiO2 samples coated in peroxo titania sol exhibited the most superior photocatalytic degradation of methylene blue aqueous solution under ultra-violet and visible light irradiations. [ABSTRACT FROM AUTHOR]

Glass-ceramic materials were obtained by heat treatment (960 ºC for 2, 4, and 6 hs) of glasses with CaCO3 47.50 wt%-TiO2 23.75 wt%-SiO2 23.75-Al2O3 5.00 wt% formulation produced by the melt-quenching technique (melting at 1650 ºC and subsequent annealing at 650 ºC). The materials’ structural characterization and crystallization kinetics (Kissinger method) indicate the presence of CaTiO3, CaSiO3, and CaTiSiO5 crystalline phases with activation energies 217, 281, and 446 kJ/mol, respectively. The structure refinement (Rietveld method) suggests metastability for the CaSiO3 and CaTiSiO5 phases as a function of the heat treatment time. The increase in time favors CaTiO3 crystallization, from 62.97 wt%, in the 2 hs treated sample, to 79.21 wt%, in the 6 hs treated sample. EDS and microstructure analyses confirm the glass-ceramic production and indicate segregation of the CaTiO3 phase for longer heat treatment times.

Near-infrared (NIR) persistent luminescence (PersL) materials have interesting invisible self-luminescent properties, but most of them can only be effectively activated by UV light. In the present study, Ca 0.97 TiO 3 :Y 0.02 (CaTiO 3 :Y) is found with visible-light-excited PersL at ∼770 nm lasting at least for 5 h. The PersL is derived from the broad absorption of Ti3+, which is stabilized by Y3+-doping via a charge compensation strategy. The PersL excitation spectrum has a peak at ∼ 400 nm, extending to 720 nm. Y3+-doping at Ca2+ site stimulates the generation of more oxygen vacancies and the stabilization of luminescent Ti3+. The Cr-free property makes CaTiO 3 :Y an environmentally friendly anti-counterfeiting luminescent material. The interaction between narrow band gap CaTiO 3 and proper energy levels of Ti3+ is of vital importance in the successful development of visible-light-excited PersL materials. This study provides a new member of Cr-free NIR PersL material with intense visible-light-excited luminescent property and has certain guidance on developing other visible-light-excited PersL materials. • CaTiO 3 :Y 0.02 was synthesized with visible-light-excited persistent luminescence at ∼770 nm. • The room-light-activated persistent luminescence lasted for more than 5 h. • The persistent luminescence was derived from Ti3+ emission. • Y3+ stabilized Ti3+ via charge compensation during the annealing synthesis process in air. • CaTiO 3 :Y 0.02 has potential application as an environment-friendly anti-counterfeiting material. [ABSTRACT FROM AUTHOR]

Various proportions of ZrO2/CaTiO3 powders were mixed and hot pressed at 1500°C/30 min for Ti casting. The hot‐pressed ZrO2/CaTiO3 composites were reacted with pure Ti at 1700°C/10 min in Ar. The interfacial reaction between Ti and ZrO2/CaTiO3 composites was investigated through X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, and energy‐dispersive X‐ray spectroscopy. The ZrO2/CaTiO3 composites with less than 10 vol.%, CaTiO3, and a minor amount of residual TiO2 were found. When the content of ZrO2 was increased to larger than 10 vol.%, two Ca2Zr5Ti2O16 and CaZrTi2O7 phases appeared in the composites. The amount of CaTiO3 and CaZrTi2O7 in the composites gradually decreased as the amount of ZrO2 increased. When Ti came in contact with ZrO2/CaTiO3 composites with less than 10 vol.% ZrO2, the resulting eutectic reaction produced a liquid phase and induced melting. When ZrO2 was increased to more than 30 vol.% in the composites, Ca2Zr5Ti2O16 and CaZrTi2O7 changed completely to CaZrO3, Ti2O, CaO, and ZrO2. With more than 30 vol.% ZrO2, no other reaction phases occurred in the Ti side after contact with the ZrO2/CaTiO3 composites, which is conducive for producing ceramic composites for Ti casting applications. [ABSTRACT FROM AUTHOR]