Chemical Solution Decomposition Research Articles

Photodegradation of dye wastewater by Ti doped Bi2O3/montmorillonite composites

Ti-doped Bi2O3/montmorillonite composites (TBM) were synthesized via chemical solution decomposition using tetrabutyl titanate and bismuth nitrate pentahydrate as titanium and bismuth sources, with sodium montmorillonite as the carrier. The active brilliant blue KN-R, carmine, and rose red B solutions were employed for adsorption and degradation experiments. Characterization of the composite was done through XRD, SEM, BET, and UV-Vis DRS analyses. Results indicate that the optimal degradation performance is achieved when the Ti doping ratio is 4 % (4TBM). The removal rates for active brilliant blue KN-R, carmine, and rose red B solutions were 98.17 %, 98.29 %, and 96.77 %, respectively. Bi2O3 was found in a tetragonal phase, with Ti ions doping into the lattice of Bi2O3 as Ti4+ inhibiting grain growth. The montmorillonite flakes in the composite were exfoliated, leading to an increased specific surface area of 4.16 m2/g. Following Ti doping, Ti 3d, O 2p, and Bi 6 s orbitals combined to form a valence band of 4TBM, reducing the band gap from 2.59 eV to 2.52 eV. This enhancement in light absorption capacity improved the photocatalytic degradation performance of 4TBM.

Nanoarchitectonics of zirconium modified ZnTiO3 for photo and electro-catalysts in dye degradation and water splitting applications

Perovskite oxides are attractive in the catalytic application owing to their stability, tuning characteristics, and easy synthesis process. Here, ZnTi1-xZrxO3 (x = 0.5) (abbreviated as ZZT0.5) is synthesized under the chemical precursor solution decomposition method and calcined at 700 °C for 3 h. The cubic phase nanosized material exhibits cubic shape morphology with the proper ratio of the existing elements as from observed structural and morphological characterizations. In the photocatalytic dye degradation under natural sunlight irradiation, the materials show >90% color degradation of congo red and murexide. The observed result in the presence of solar light irradiation highlights an elevated photocatalytic efficiency. The pseudo-first-order degradation process shows a high correlation coefficient with good stability of the material in the reusable study. This ZnTiO3-based perovskite material has not been used previously in electrocatalytic water splitting. During oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) conditions, the material deposited on NF substrate showed 335 mV and 165 mV overpotential at 10 mA cm−2 current density, respectively which is indicative of notable electrocatalytic water splitting activity of the perovskite material designed herein. The long-term chronoamperometry (CA) study confirms the material's stability during both HER and OER conditions with negligible loss in activity over a period of 12 h. The post-catalytic characterizations confirm the robust nature of the material possessing the same phase characteristics. As an earth-abundant, low-cost material, the material designed herein shows the significant activity of environmental sustainability in terms of water treatment as well as green hydrogen production via electrolysis.

Photocatalytic degradation of reactive brilliant blue KN-R by Ti-doped Bi2O3.

In this study, different compositions of Ti-doped Bi2O3 photocatalytic materials were prepared by chemical solution decomposition method. It was used to degrade reactive brilliant blue KN-R, and then characterized by XRD, SEM, UV-vis DRS, XPS, photocurrent, and other detection methods. The results show that when the catalyst dosage is 1.0g/L and the initial concentration of reactive brilliant blue KN-R is 20mg/L, the degradation rate of pure Bi2O3 to reactive brilliant blue KN-R is 75.30%; the Ti doping amount is 4% (4Ti/Bi2O3), 4Ti/Bi2O3 had the best degradation effect on reactive brilliant blue KN-R, and the degradation rate could reach 93.27%. When 4Ti/Bi2O3 was reused for 4 times, the degradation rate of reactive brilliant blue KN-R only decreased by 6.91%. Doping Ti can inhibit the growth of Bi2O3 grains, making the XRD peak of Ti/Bi2O3 material wider. The pure Bi2O3 particles are larger and the surface is smooth. With the increase of Ti doping content, the surface of Ti/Bi2O3 material grows from roughness to nanofibrous Bi4Ti3O12. The visible light absorption performance and electron separation and transfer ability of Bi2O3 are significantly improved by doping Ti ions. The band gap is reduced from 2.81 to 2.75eV. In conclusion, doping Ti enhances the visible light absorption and electron separation and transfer capabilities of Bi2O3, reduces the band gap, and improves the surface morphology, which makes Bi2O3 have higher photocatalytic performance.

Observation of electrical and energy storage properties of lead-free transition metal-doped BaBi2(NbTa)O9 nanoceramics prepared through chemical route

A-site doping of BaBi2NbTaO9 by Ni2+ was synthesized by chemical precursor solution decomposition method. The materials exhibited single-phase tetragonal structure. The crystallite size of the calcined powder exhibited 42 nm with high degree of tetragonality. Curie temperature (Tc) was not found upto 600 °C that indicated higher Tc of the material. Impedance spectroscopy showed non-Debye type of relaxation with semiconducting nature. The closeness of the activation energy for imaginary impedance relaxation and DC conductivity indicated same type of charge carriers. P–E hysteresis loop indicated ferroelectric properties of the material. Energy storage densities were calculated for charge and discharge. The highest energy efficiency was observed at 10 kV/cm electric field.

Influence of La3+ and V5+ doping on the polarization and impedance behaviour of BaBi2Nb2O9 nano-ceramics prepared by chemical route

The effect after the incorporation of La3+ and V5+ on BaBi2Nb2O9 ceramics was investigated by the analysis of structural and electrical studies. The materials are synthesized using chemical precursor solution decomposition method. Single orthorhombic phase was established after calcined the precursor mass at 700 °C for 3 h studied using X-ray diffraction study. The morphology of the samples was studied using scanning electron micrograph and transmission electron micrograph. The Curie temperature was increased with increasing substitution. High relaxation behaviour was observed during impedance spectroscopy study. For higher substitution both grain and grain boundary conductivity appears in the samples. The dc activation energy was in the range of 1.13–1.43 eV which are lower than the relaxation activation energy. The polarization of all the samples increases with increasing electric field. BBLNV0.5 showed the highest energy efficiency about 86%.

Effect of Cu2+ substitution on the relaxor behavior of BaBi2Nb2O9 ferroelectric nanoceramics prepared by chemical route

Ba0.5Cu0.5Bi2Nb2O9 (BCuBN) crystalline nano ceramics were prepared by chemical precursor solution decomposition method. A structure property correlation of BCuBN done through dielectric impedance, density of states, hopping mechanism and discharge polarization study after the incorporation of Jahn-Teller active Cu2+ (d9, s = ½) ions. X-ray diffraction study, scanning electron microscopy demonstrated the orthorhombic structure with A21am space group of BCuBN. Ferroelectric to paraelectric phase transition temperature (Tc) obtained in the temperature range from 515 °C to 545 °C at different frequency range. The activation energy of relaxation behaviour in complex imaginary impedance plot with frequency is 0.80 eV closer to dc conductivity (0.73 eV). The frequency dependent ac conductivity becomes much higher at higher frequency. The density of states and hopping mechanism were successfully explained here. The field induced polarization hysteresis loops demonstrated the pseudo static saturation of polarization. Maximum discharge energy density was 1.12 J cm−3 at 10 kV cm−1 electric field.

Dielectric anomaly, diffusivity and impedance behavior of transition metal substituted SrBi2NbTaO9 ferroelectric nano-ceramics prepared by chemical route

Dielectric, impedance, ac and dc conductivity of transition metal ions Co2+, Ni2+ and Cu2+ substituted at Sr- site of SrBi2NbTaO9 (SBNT) nanoceramics have been investigated throughout the manuscript. Nanosized Sr0.5Co0.5Bi2NbTaO9, Sr0.5Ni0.5Bi2NbTaO9 and Sr0.5Cu0.5Bi2NbTaO9 were synthesized by chemical precursor solution decomposition method. All of the ceramics showed orthorhombic structure proved from X-ray diffraction study that matched with JCPDS data file no. 86-1190. The unit cell volume, crystallite size, grain size were high for Sr0.5Cu0.5Bi2NbTaO9. Substitution of smaller ionic radius at Sr- site also leads to the distortion as well as oxygen vacancy in the ceramics that leads to the relaxor behavior of the materials. Dielectric anomaly was clearly observed with diffused phase transition for Cu-substituted sample. However, dielectric loss of Cu-substituted sample was little higher with respect to Ni- and Co- substituted SBNT ceramics. The relaxation of all ceramics was clearly observed from dielectric and impedance study. The high dielectric constant was observed for Sr0.5Cu0.5Bi2NbTaO9.

Synthesis of Dy3+ co-doped Bi4Si3O12:Sm3+ phosphors with enhanced red-emitting properties

Abstract [Bi 4 Si 3 O 12 :Sm 3+ , Dy 3+ ] samples were prepared by the chemical solution decomposition method. The effects of different Bi 3+ and Si 4+ ion ratio in solution, as well as calcination temperature, on the synthesis of Bi 4 Si 3 O 12 phosphor were investigated. The influence of co-doped Dy 3+ ions on the red emission performance of [Bi 4 Si 3 O 12 :Sm 3+ ] phosphors and the mechanism of interaction between Sm 3+ and Dy 3+ ions were examined. X-ray diffraction (XRD) and scanning electron microscopy (SEM) showed that pure phase Bi 4 Si 3 O 12 power sample with good morphology/structure was obtained at Bi 3+ :Si 4+ ion ratio of 1:2 and calcination temperature of 800 °C. The data also revealed that small amounts of rare earth ions in Bi 4 Si 3 O 12 did not greatly impact the crystal structure and particle morphology. Photoluminescence spectroscopy indicated that the emission peak of [Bi 4 Si 3 O 12 :Sm 3+ , Dy 3+ ] phosphors was similar to that of Bi 4 Si 3 O 12 :Sm 3+ . The peak was recorded at 606 nm and it was assigned to the 4 G 5/2 → 6 H 7/2 transition of Sm 3+ ions. The highest luminous performance of the phosphor was obtained at Sm 3+ and Dy 3+ ions doping concentrations of 4 mol% and 1 mol%, respectively. At λ ex = 387 nm and λ ex = 451 nm (Dy: 6 H 15/2 → 4 I 11/2 , 6 G 11/2 ), the emission spectra of [Bi 4 Si 3 O 12 :Sm 3+ , Dy 3+ ] phosphors depicted the characteristic peaks of Dy 3+ and Sm 3+ ions, indicating that energy could transferred from Dy 3+ to Sm 3+ and it promotes the luminescence of Sm 3+ .

Enhanced dielectric tunability of W-doped Na0.5Bi0.5TiO3 thin film by moderating the precursor solution concentration

W-doped Na0.5Bi0.5TiO3 (NBTW) thin films with different solution concentrations of 0.05, 0.10, 0.20 and 0.40 M were deposited on indium tin oxide/glass substrates via chemical solution decomposition combined with sequential layer annealing. The role of precursor solution concentration on microstructure and dielectric tunability was mainly studied. All films crystallize into the single perovskite structures with an obvious difference in relative intensities of all peaks. The ratio of the (l00) and (110) diffraction peaks intensity reaches to the maximum value for the 0.10 M-film. Compared with the other films, the NBTW film prepared from 0.10 M exhibits the low leakage current due to the relatively dense microstructure with uniform grain size. Besides, a high dielectric tunability of 53 % and figure of merit of 11.5 for the NBTW film derived from 0.10 M precursor solution can be obtained at ±8 V and 100 kHz. These results suggest that the appropriate concentration of precursor solution is of great significance for enhancing the dielectric performance of NBTW thin film.

Substrate-dependent ferroelectric and dielectric properties of Mn doped Na0.5Bi0.5TiO3 thin films derived by chemical solution decomposition

Na0.5Bi0.5(Ti0.98Mn0.02)O3 (NBTMn) thin films have been fabricated on Pt/TiO2/SiO2/Si and LaNiO3 (LNO)/Si substrates via chemical solution decomposition. The microstructure, ferroelectric and dielectric properties were investigated. Both films on different substrates can be crystallized into the phase-pure perovskite structures. The NBTMn thin film deposited on Pt/TiO2/SiO2/Si substrate shows random orientation with (l00) and (110) diffraction peaks, while the sample on LNO/Si exhibits preferred orientation with strong diffraction peaks of (l00). The NBTMn thin film deposited on LNO/Si substrate exhibits a denser and smoother microstructure. Compared with the round shaped polarization-electric field hysteresis loops of NBTMn on Pt/TiO2/SiO2/Si substrate, the enhanced ferroelectric property can be observed in NBTMn thin film fabricated on LNO/Si with a remanent polarization (Pr) of 10.2 μC/cm2 due to the reduced leakage current. The dielectric tunabilities of two films increase gradually with the increasing of applied voltage, and the sample on LNO/Si substrate has a relatively larger dielectric tunability with 20% at 14 V and 1 MHz.

The structure, ferroelectric and dielectric properties of Na0.5Bi0.5(Ti0.98Mn0.02)O3 thin film prepared by chemical solution decomposition

Na0.5Bi0.5(Ti0.98Mn0.02)O3 (NBTMn) thin film was fabricated on fluorine-doped tin oxide (FTO)/glass substrate via a chemical solution decomposition method. The microstructure and electrical performances of NBTMn thin film were investigated. The XRD pattern reveals that the NBTMn thin film is crystallised into a phase-pure polycrystalline perovskite structure. Also the film possesses a homogeneous structure. Enhanced ferroelectricity is obtained with a large remnant polarisation (Pr) of 19.8 μC/cm2 reflected by polarisation–electric field (P–E) hysteresis loop, which is consistent with the typical butterfly-shaped capacitance–voltage (C–V) curve. At the optimum applied voltage of ±22 V, a maximum value of 27% for dielectric tunability is obtained. Additionally, the NBTMn thin film shows a dielectric constant of 422, dissipation factor of 0.06 and figure of merit of 4.5 at 100 kHz.

Effects of Zr doping content on microstructure, ferroelectric and dielectric properties of Na0.5Bi0.5TiO3 thin film

Ion-doping is a key factor affecting the microstructure and electrical properties of Na 0.5 Bi 0.5 TiO 3 (NBT) thin film. In this paper, Na 0.5 Bi 0.5 (Ti 1− x Zr x )O 3 ( x =0, 0.01, 0.02, 0.04) thin films were prepared using chemical solution decomposition and the effects of Zr 4+ doping content on crystalline, ferroelectric and dielectric properties were characterized. Compared with the other films, NBT with 2 mol% Zr 4+ doping content exhibits enhanced ferroelectricity with a remanent polarization ( P r ) of 12.3 μC/cm 2 due to the high densification, as well as reduced leakage current and distortion of Ti–O octahedral. The dielectric constant ( ε r ) and dissipation factor (tan δ ) on frequency show small dispersion tendency with ε r of 263 and tan δ of 0.067 at 100 kHz. Also, the capacitance–voltage curve displays a relatively sharp feature with a high dielectric tunability of 61.6%. • NBTZr 0.02 shows a well-defined P–E with a remanent polarization of 12.3 μC/cm 2 . • The high densification and Ti–O distortion favor the enhanced ferroelectricity. • The dependence of ε r on frequency for NBTZr 0.02 film has small dispersion tendency. • At 100 kHz, for NBTZr 0.02 , ε r =263, tan δ =0.067, dielectric tunability=61.6%.

EFFECTS OF PRECURSOR SOLUTION MODIFICATION ON THE CRYSTALLINITY AND ELECTRICAL PROPERTIES OF Na0.5Bi0.5TiO3-BiFeO3 BASED THIN FILM

For chemical solution decomposition process, the precursor solution is a basic factor affecting the quality of the deposited-film. In this paper, we choose (l00)-oriented 0.7[( Bi 0.95 Ce 0.05)0.5 Na 0.5( Ti 0.99 Fe 0.01) O 3]-0.3 BiFe 0.97 Mn 0.03 O 3(0.7 NBTCeFe -0.3 BFOMn ) thin films prepared by various precursor solutions for investigation. The roles of precursor solution modification on crystallinity, ferroelectric and dielectric properties are characterized. With the addition of polyethylene glycol into the solution, phase-pure perovskite structure can be obtained. Furthermore, when the volume ratio for the solvents (ethylene glycol to acetic acid) is modified as 2:1, enhanced ferroelectricity can be achieved with a remanent polarization (Pr) of 27.5 μC/cm2, which coincides well with the capacitance–voltage curve with relatively sharp feature. Also, the 0.7 NBTCeFe -0.3 BFOMn film exhibits a dielectric constant (εr) of 576 and dielectric loss (tan δ) of 0.123 at 100 kHz.

Dielectric tunability of highly (l00)-oriented Fe-doped Na0.5Bi0.5TiO3 thin film

Highly (l00)-oriented Na0.5Bi0.5(Ti0.99Fe0.01)O3−δ (NBTFe) thin film was deposited on LaNiO3(100)/Si substrate via a chemical solution decomposition process. A high dielectric tunability of 29.36% for the NBTFe thin film is obtained at the optimum voltage (20V) and frequency (100kHz). The NBTFe film shows a dielectric constant of 400, dissipation factor of 0.122 and figure of merit of 4.78 at 100kHz by the measurements of dielectric constant and dissipation factor as a function of frequency. These results demonstrate that the NBTFe thin film has a strong potential for utilization in tunable devices.

Surface morphology and ferroelectric properties of compositional gradient PZT thin films prepared by chemical solution deposition process

A series of PbTiO3/PbZrxTil−xO3 (PT/PZT) and PbZrO3/PbZrxTil−xO3 (PZ/PZT) compositional gradient thin films are obtained by chemical solution decomposition (CSD) method. The influences of buffer layers on surface morphology are investigated. Thin films with buffer layer are able to maintain the perovskite structure with (111)-preferred orientation. The surface microstructure and ferroelectric properties of the PZT thin films differs significantly depending on the use of PT or PZ buffer layers. When the PT buffer layer has five layers, the root mean square roughness (RMS) [17.7nm] and remnant polarization (Pr) [35.83μC/cm2] are maximized. On the other hand, when PZ buffer layer has one layer, the RMS [3.67nm] and Pr [26.08μC/cm2] are also maximized. The down-graded (Zr composition varying from 0.6 at the bottom surface to 0.4 at top surface) thin films exhibit larger surface roughness and better ferroelectric property than up-graded (Zr composition varying from 0.4 at the bottom surface to 0.6 at top surface) thin films. Therefore, different buffer layer determines different surface morphology. It is concluded that the ferroelectric property of the gradient thin films not only depends on its composition structure, but can also be controlled by the surface morphology. The results indicate that the PZT films with better ferroelectric property should have larger surface roughness.

COMBINATORIAL PREPARATION AND FERROELECTRIC PROPERTIES OF COMPOSITIONALLY GRADIENT PZT THIN FILMS

Using a combinatorial synthesis process, compositionally gradient PZT thin films were conveniently prepared by a chemical solution decomposition (CSD) method. The thin films showed a perovskite structure with (111)-preferred orientation and a thickness of around 450 nm. The surface morphology and ferroelectric properties were significantly different, depending on the direction of compositional gradient. The detailed composition and gradient of the composition was seen to affect the property of compositionally gradient PZT thin films. The gradient thin film PZT654, with a Zr:Ti ratio of 6:4 at the bottom of the film nearest to the substrate, and with an total composition around the morphotropic phase boundary (MPB, x = 0.52) showed favorable ferroelectric properties. However, no typical offset of the hysteresis loops was observed in our work.

Preparation, structural and linear optical properties of zinc sillenite (Bi12.66Zn0.33O19.33) nanocrystals

To prepare zinc sillenite nanopowders, bismuth nitrate and zinc nitrate were taken in 12:1 and 12.66:0.33 mol ratios. Zinc sillenite (Bi12.66Zn0.33O19.33) nanocrystalline powder was prepared by simple chemical solution decomposition method via heat treatment. Studies were focused on the formation of single crystalline phases and their linear optical properties. TG–DTA, XRD, DRS, IR, Raman, FE-SEM–EDS, and TEM techniques were used systematically to characterize the zinc sillenites. X-ray powder diffraction studies confirm that the heat treatment at 650 °C leads to cubic structure with zinc sillenites phase. Lattice parameter and the band gap of zinc sillenite were estimated as (a=) 10.21 A and 2.75 eV respectively. We could observe the bismuth-oxygen sublattice vibrational modes alone in the Raman/IR vibrational spectra of zinc sillenite.

Single cell lysis and DNA extending using electroporation microfluidic device

The purpose of cell lysis is to obtain intracellular substances such as DNA and proteins for analysis. Commonly used methods include chemical (chemical solution decomposition) and physical (electricity or mechanical force). This study proposes an integrated system using an electroporation and microfluidic device made by micro-photolithography to lyse a single cell and stretch its DNA. The PDMS, as the manufacturing material of the microfluidic device, consists of 2 parts: the cell lytic zone, in which the immobilized cells trapped within the dense microstructure are lysed at a single-cell level, and the DNA stretching and recovery zone. This study showed that in a hypotonic environment (75 mM glucose solution), when electric field conditions were 100 Vpp and 1 kHz, the target cell was lysed and its DNA was released into the solution. When injected with proteinase K, the DNA flowed along the rectangular microstructure and was stretched to a length exceeding 840 μm.

Photocatalytic degradation kinetics and mechanism of pentachlorophenol based on Superoxide radicals

The micron grade multi-metal oxide bismuth silicate (Bii 2SiO 20, BSO) was prepared by the chemical solution decomposition technique. Photocatalytic degradation of pentachlorophenol (PCP) was investigated in the presence of BSO under xenon lamp irradiation. The reaction kinetics followed pseudo first-order and the degradation ratio achieved 99.1% after 120 min at an initial PCP concentration of 2.0 mg/L. The pH decreased from 6.2 to 4.6 and the dechlorination ratio was 68.4% after 120 min at an initial PCP concentration of 8.0 mg/L. The results of electron spin resonance showed that Superoxide radical (O 2 ·−) was largely responsible for the photocatalytic degradation of PCP. Interestingly, this result was different from that of previous photocatalytic reactions where valence band holes or hydroxyl radicals played the role of major oxidants. Some aromatic compounds and aliphatic carboxylic acids were determined by GC/MS as the reaction intermediates, which indicated that O 2 ·− can attack the bond between the carbon and chlorine atoms to form less chlorinated aromatic compounds. The aromatic compounds were further oxidized by O 2 ·− to generate aliphatic carboxylic acids which can be finally mineralized to CO 2 and H 2O.

Structural, linear and enhanced third-order nonlinear optical properties of Bi 12SiO 20 nanocrystals

This paper reports the structural, linear and nonlinear optical properties of bismuth silicon oxide (BSO) nanocrystals with grain size from 60 to 150 nm synthesized by chemical solution decomposition (CSD) method. The X-ray diffraction, FTIR, and micro Raman studies revealed the formation of pure single phase cubic structured BSO nanocrystals at 700 °C of calcination temperature. TEM studies have confirmed the size and the presence of crystalline phase of the BSO nanocrystals. Linear optical properties studied through the UV–visible spectrum showed the presence of a “blue shifted” peak around 270 nm corresponding to a band gap of 4.6 eV due to the formation of nanophase crystals. The nonlinear optical properties studied using a standard open aperture z-scan showed strong nonlinear absorption both with nanosecond and picosecond pulsed excitations. In addition to the nonlinear absorption mechanism, nonlinear scattering was also observed to contribute to the reverse saturable absorption (RSA) behavior leading to a very high RSA behavior in both the time regimes.