Concentration Of H3BO3 Research Articles

The effect of boric acid concentration on the TiO2 compact layer by liquid-phase deposition for dye-sensitized solar cell

In this study, we prepared titanium oxide (TiO2) compact-layer thin films (thickness: 50 nm) on an indium tin oxide (ITO)/glass substrate by liquid-phase deposition (LPD) for the dye-sensitized solar cell (DSSC). We used a deposition solution of ammonium hexafluoro-titanate and boric acid (H3BO3) for the TiO2 film. We varied the concentration of H3BO3 from 0.4 to 0.7 M to control the deposition rate, surface roughness, and refractive index of the TiO2 film. Based on the results of X-ray diffraction and transmission electron microscopy, the TiO2 films all possessed the polycrystalline feature with (101), (004), (200), (105), and (211) planes. After the LPD deposition, we can observe that the formation of the transition-layer existed in the TiO2 film. The transition-layer is analyzed as In and Sn co-doped TiO2 film, which is caused by the diffusions of In3+ and Sn4+ ions from the ITO substrate. From the depth profiles of X-ray photoelectron spectroscopy, the thickness of the transition-layer increased with a decrease of the boric acid concentration. At the optimum H3BO3 concentration of 0.5 M, we obtained the following photovoltaic properties: a short circuit current density (Jsc) of 11.41 mA/cm2, an open circuit voltage (Voc) of 0.73 V, a fill factor (ff) of 0.63, and an efficiency (η) of 5.24%. The LPD-TiO2 compact-layer between the ITO and the DSSC photo-electrode can reduce the number of carrier recombinations and improve transmittance in the visible light region. The TiO2 compact-layer prevents electron transport to the electrolyte and results in a higher Jsc. Moreover, the LPD-TiO2 compact-layer can enhance interface adhesion and improve the series resistance.

Optimization method for blue Sr2MgSi2O7:Eu2+, Dy3+ phosphors produced by microwave synthesis route

We report a kind of dopant (Eu2+) and co-dopant (Dy3+) co-doped strontium magnesium silicate phosphor synthesized via microwave irradiation in a weak reductive atmosphere of active carbon. X-ray diffraction (XRD) patterns illustrated that the samples were nearly pure Sr2MgSi2O7 phase, in which the Sr2MgSi2O7 host phase has the maximum fraction of tetragonal crystallography Sr2MgSi2O7 phase. A series of long afterglow luminescent materials were synthesized to investigate the best synthetic conditions. The results showed that the optimal concentration of H3BO3 and the best sintering time were 5 wt% and 30 min, respectively. The phosphors made from the microwave irradiation method demonstrated excellent luminescence performance and the microwave irradiation method provide a strategy for the synthesis of other alkali earth aluminate and silicate, or other luminescent materials.

Experimental Investigation of Biotite-Rich Schist Reacting with B-Bearing Fluids at Upper Crustal Conditions and Correlated Tourmaline Formation

Fluid–rock interaction experiments between a biotite-rich schist (from Mt. Calamita Formation, Elba Island, Italy) and B-bearing aqueous fluids were carried out at 500–600 °C and 100–130 MPa. The experiments have been carried out in order to reproduce the reaction, which would have produced tourmalinisation of the biotite schist, supposedly by circulation of magmatic fluids issued from leucogranitic dykes. The reacting fluids were either NaCl-free or NaCl-bearing (20 wt %) aqueous solutions, with variable concentration of H3BO3 (0.01–3.2 M). The experimental results show that tourmaline (belonging to the alkali group) crystallise under high-temperature and upper crustal conditions (500–600 °C, 100–130 MPa) when H3BO3 concentration in the system is greater than 1.6 M. The composition of tourmaline is either dravitic (Mg-rich) or schorlitic (Fe-rich), depending if an NaCl-bearing or NaCl-free aqueous solution is used. In the first case, a significant amount of Fe released from biotite dissolution remains in the Cl-rich solution resulting from the experiment. By contrast, when pure water is used, Na/K exchange in feldspars makes Na available for tourmaline crystallisation. The high concentration of Fe in the residual fluid has an important metallogenic implication because it indicates that the interaction between the saline B-rich fluid of magmatic derivation and biotite-rich schists, besides producing tourmalinisation, is capable of mobilising significant amounts of Fe. This process could have produced, in part or totally, the Fe deposits located close to the quartz–tourmaline veins and metasomatic bodies of the Mt. Calamita Formation. Moreover, the super-hot reservoir that likely occurs in the deepest part of the Larderello–Travale geothermal field would also be the site of an extensive reaction between the B-rich fluid and biotite-bearing rocks producing tourmaline. Thus, tourmaline occurrence can be a useful guide during deep drilling toward a super-hot reservoir.

Analysis of Accumulation and Crystallization of Boric Acid in the Reactor Core during WWER Emergency Operation

The results of hand calculation of boric acid accumulation in the core in a new generation WWER-TOI reactor in case of LOCA are presented. Variants of reducing the H3BO3 concentration in the HA-3 system down to 1, 2, 4 and 8 g/kg are considered. The mass of boric acid deposits on the core internals depending on the value of boric acid concentration in the HA-3 system is determined. The obtained results allow concluding that the accumulation and crystallization of boric acid in the core is possible.

Effect of acid addition on hydrogen production from potassium borohydride hydrolysis

ABSTRACTThis is the first study to produce hydrogen from the potassium borohydride (KBH4) hydrolysis using boric acid (H3BO3). The effect of H3BO3 addition on the hydrogen production via KBH4 hydrolysis was investigated for different H3BO3 and KBH4 molar ratios. In addition, the temperature effect on the hydrolysis reaction was investigated at different temperatures. H3BO3 showed good catalytic activity to produce hydrogen from KBH4 hydrolysis. Activation energy to produce hydrogen from KBH4 hydrolysis was found to be 20.31 kJ/mol. This work also includes kinetic information for the hydrolysis of KBH4. According to the kinetic studies, the reaction between H3BO3 and KBH4 had a reaction order of 0.24 against the H3BO3 concentration, while it had a reaction order of 0.16 against the KBH4 concentration.

Microstructure developments and anti-reflection properties of SiO2 films by liquid-phase deposition

In this work, silicon dioxide (SiO2) films were deposited on a multi-crystalline silicon substrate via liquid-phase deposition (LPD) using hydrofluorosilicic acid (H2SiF6) and boric acid (H3BO3) aqueous solution. We controlled the surface morphology and grain structure of the film by using the concentration of H2SiF6, and the particle sizes were controlled by the concentration of H3BO3. Fourier transform infrared spectroscopy showed that three SiOx peaks exist at 1103, 815, and 463cm−1, respectively. X-ray diffraction revealed a typical broad peak in the range of 14–55° for the SiO2 amorphous particles. The refractive index of the LPD film was 1.41. The reflection of the LPD SiO2 film was affected by the film thickness, and the reflectivity of the film was decreased as the film thickness increased. For the 106nm SiO2 film thickness, the average reflectance under the measuring conditions was 14.1%. The low reflectance rendered the film a suitable anti-reflection film in multi-crystalline silicon solar cells.

Effect of H3BO3 on phases, micromorphology and persistent luminescence properties of SrAl2O4: Eu2+, Dy3+ phosphors

Long afterglow material SrAl2O4: Eu2+, Dy3+ were synthesized by solution combustion method, and the effects of the concentration of H3BO3 on phases, micromorphology, photoluminescence properties, long afterglow properties and thermoluminescence glow curves of the phosphors were studied systematically. Phosphor with SrAl2O4 pure phase can be obtained when the concentration of H3BO3 is 2 mol%. The micromorphology of the phosphors changed a lot due to the varied amount of H3BO3, and nanoflower like phosphors was formed when the concentration of H3BO3 is 10 mol%. With the continue increasing of H3BO3, the nanoflower aggregate together to form irregular particles with a larger size and the petal gradually disappear while the luminescence intensity shows a linear increase. The decay curves and the Thermoluminescence glow curves were also measured, and the depth of traps were calculated. The results show that with the increasing concentration of H3BO3, the trap depth increasing gradually. However, the trap depth decrease gradually when the content of H3BO3 beyond 20 mol%, which caused by the diffusion of surplus B3+ in the interstitial sites.

Influence of H<sub>3</sub>BO<sub>3</sub> addition on mechanoluminescence property of SrAl<sub>2</sub>O<sub>4</sub>:Eu<sup>2+</sup>

Eu-doped strontium aluminates (SrAl2O4:Eu2+) has been attracting attention as a highly potential mechanoluminescent (ML) material in a wide range of applications such as visualization of stress distribution for the concretes, steel materials, etc. In this study, we examined the single effect by the addition of flux, boric acid (H3BO3), in the synthesis process for the improvement of the ML intensity of SrAl2O4:Eu2+. Crystal structure, photoluminescence and ML properties were examined at various H3BO3 concentrations. It was found that the addition of H3BO3 provided 2.5 times improvement of ML intensity. This is probably due to the increase in the trap concentration.

Corrosion Behavior of B4C/6061Al Neutron Absorber Composite in Different H3BO3 Concentration Solutions

In this study, electrochemical corrosion tests, full-soak corrosion tests and associated microstructure analysis were conducted to investigate the corrosion behaviors of B4C/6061Al neutron absorber composites (NACs) manufactured by powder metallurgy method in solutions having different boric acid (H3BO3) concentrations (500, 2500 and 10,000 ppm). In electrochemical corrosion tests, B4C/6061Al NACs demonstrate the highest (short-term) corrosion resistance in the 2500 ppm H3BO3 solution. While for full-soak corrosion tests, the B4C/6061Al NACs show the highest (long-term) corrosion resistance in the 500 ppm H3BO3 solution. This difference is found to be mainly due to the formation of different surface morphologies during these two different corrosion tests. As noticed, a layer of Al(OH)3 was formed on the composite surface during full-soak corrosion tests, but it cannot be found in the electrochemical corrosion tests. The full-soak corrosion mechanism of the B4C/6061Al NACs in the H3BO3 solution is found to be primarily determined by the dynamic balance between the formation and dissolution rates of the oxide film, which is mainly controlled by the density of H+ ions in the solution.

Orthogonal test design for optimising the culture medium for in vitro pollen germination of feijoa (Acca sellowiana cv. Unique)

ABSTRACTFeijoa suffers from high rates of flower and fruit abortion, and widely varying fruit characteristics, which are directly related to pollination problems. However, efficient pollination mostly depends on pollen vigour. Thus, methods to improve pollen vigour have become an important focus for both breeders and growers. An orthogonal design method (L9[3]4) was used to compare the effectiveness of key factors (e.g. concentrations of sucrose, H3BO3, CaCl2 and GA3) to determine pollen vigour, and to optimise the culture medium for in vitro pollen germination. The four factors that influenced pollen germination in order of significance are as follows: GA3 > CaCl2 > H3BO3 > sucrose. These variables influenced pollen tube growth in the following order: CaCl2 > H3BO3 > sucrose > GA3. The optimal culture medium for promoting pollen vigour was 10% sucrose, 1.95 × 10–3 mol/L H3BO3, 4 × 10–4 mol/L CaCl2 and 80 mg/L GA3.

Reverse osmosis for the recovery of boric acid from the primary coolant at nuclear power plants

At nuclear power plants (NPP), evaporators are used for the treatment of primary coolant and other liquid radioactive waste containing H3BO3. Because the operation of evaporators is expensive, a number of more cost-effective alternatives has been considered, one of which is reverse osmosis. We tested reverse osmosis modules from several manufactures on a batch laboratory apparatus. SEM images of the tested membranes were taken to distinguish the differences between the membranes. Water permeability through membranes was evaluated from the experiments with pure water. The experiments were performed with feed solutions containing various concentrations of H3BO3 in a range commonly occurring in radioactive waste. The pH of the feed solutions ranged from 5.2 to 11.2. Our results confirmed that the pH of the feed solution plays the most important role in membrane separation efficiency of H3BO3. Certain modifications to the pH of the feed solution were needed to enable the tested membranes to concentrate the H3BO3 in the retentate stream, separate from the pure water in the permeate stream. On this basis, we propose the configuration of and operational conditions for a reverse osmosis unit at NPP.

Growth and Characterization of Ammonium Dihydrogen Phosphate (ADP) Doped with H<sub>3</sub>BO<sub>3</sub> Crystals Grown by Slow Evaporation Method

Ammonium dihydrogen phosphate (ADP) crystals is very interesting due to its nonlinear optical property. This study investigated on improving of material for academic use by adding boric acid to modify ADP crystals. Slow evaporation method in aqueous solutions of pure ADP and ADP doped with three concentrations of H3BO3 as 0.1, 1.0, 5.0 %wt were studied. The grown crystals were confirmed tetragonal structure by powder X-ray diffraction studies. The FTIR spectrum analysis presented various functional groups of boron in three conditions of doped ADP. TGA study was comfirned the temperature stability at 220 °C for both pure and doped ADP crytals. The machanical stress was analyzed by Vicker’s hardness measurement. The results of this analysis showed boric acid doped 1.0 %wt had superior machanical stress from 10 to 75 grams. ADP doped with boric acid at 1.0 %wt was accepted in all test properties.

Formation of nickel microcones by using an electrodeposition solution containing H3BO3

In this study, we fabricated the nickel microcones by using an electrodeposition solution containing boric acid (H3BO3). When electrodeposition was performed after H3BO3 had been added to the nickel electrodeposition solution, growth along the (200) direction of the nickel electrodeposition structure was suppressed while that along the (220) direction was promoted. Owing to this phenomenon, the addition of H3BO3 to the electrodeposition solution resulted in the formation of the microcones. The density of these microstructures appeared to be proportional to the concentration of H3BO3 added to the solution. Furthermore, when electrodeposition was performed using the solution containing H3BO3, sharper microcones was formed with lower applied current densities. In addition, microcones fabricated by using a solution containing 2 M H3BO3 under applied current densities of 1 or 2 mA/cm2 exhibited superhydrophobic surfaces after hydrophobic layer coating.

Effect of boric acid doped PEDOT:PSS layer on the performance of P3HT:PCBM based organic solar cells

In this study, we fabricated PEDOT:PSS film with different concentrations 0–5mg/ml of boric acid (H3BO3) doped PEDOT:PSS film as hole collector layer. Undoped and boric acid doped PEDOT:PSS films are prepared with spin coating technique and characterized by XRD, UV, AFM, FTIR and electrical conductivity measurements. We fabricated polymer solar cells in the form of ITO/PEDOT:PSS:H3BO3/P3HT:PCBM/Al. Results show that the open-circuit voltage (Voc) and the fill factor (FF) increased by introducing H3BO3 as dopant into the PEDOT:PSS layer due to an increase in the work function of PEDOT:PSS layer and improvement of surface roughness, respectively. The solar cells without H3BO3 showed a power conversion efficiency PCE of 1.79% whereas the cells with H3BO3 concentration of 1.25mg/ml in PEDOT:PSS, showed a higher performance resulting in a PCE of 2.14% under AM 1.5G illumination.

Continuous treatment of boron and fluoride in aqueous solutions using a column loaded with granulated Mg–Al layered double hydroxides intercalated with nitrates

Mg–Al layered double hydroxides intercalated with NO3− (NO3·Mg–Al LDHs) were mixed with various amounts of epoxy resin to obtain granulated NO3·Mg–Al LDH samples. The granulated NO3·Mg–Al LDH samples were shown to be capable of adsorbing B from aqueous solutions and the experimental adsorption isotherm data fit well to the Langmuir model. In order to evaluate the continuous treatment of B and F− in aqueous solutions, a chromatographic column was loaded with granulated NO3·Mg–Al LDH with an LDH/epoxy resin ratio of 1:0.5 and H3BO3 and NaF solutions were passed through the columns under various conditions. The concentrations of B and F− in the elutions were found to increase with time. In addition, the concentrations of B and F− in the elutions also increased with increase in the flow rates and initial concentrations of H3BO3 and NaF, respectively, which were attributed to the flow of large amounts of B and F− into the column in a short duration. The experimental data from the column experiments were fit to the Thomas model. The relatively high R2 values under all the conditions suggest that the Thomas model adequately represents the results of the adsorption experiments. For the adsorption of both B and F−, the calculated qT from the Thomas model showed good agreement with the experimental qE values, confirming the validity of the Thomas model for the column experiments.

Influence of fluxing agent on the luminescence properties of SrAl2O4:Eu2+ nanophosphors

Eu2+ doped strontium aluminate nanophosphors are prepared by combustion method. The X-ray diffraction (XRD) and transmission electron microscope (TEM) studies showed the emergence of mixed phase for higher concentration of H3BO3. The effect of fluxing agent H3BO3 on the phase structure and on the luminescence properties; such as mechanoluminescence (ML) and photoluminescence (PL) properties of SrAl2O4:Eu2+ nanophosphors are investigated. The variation in fluxing agent H3BO3 influenced the PL and ML intensity and the maximum PL and ML intensity was observed for 7.5% H3BO3. The PL emission and ML spectra showed broad band at 515 nm corresponding to the 4f65d1 → 4f7 transition. The PL and ML for different amount of Eu revealed that the optimal concentration of Eu is 3%. An initial rapid decay followed by long-lasting phosphorescence was observed for the synthesized samples.

Effect of boric acid composition on the properties of ZnO thin film nanotubes and the performance of dye-sensitized solar cell (DSSC)

The effect of boric acid (H3BO3) composition at constant concentration of hexamethylenetetramine (HMT) and zinc nitrate (Zn(NO3)2) on the morphology, thickness, elemental composition, optical absorption, structure, photoluminescence of ZnO nanotubes has been investigated. The performance of the DSSC utilizing the ZnO samples has also been studied. It was found that the structure, thickness, elemental composition, optical absorption and morphology of ZnO nanostructure are significantly affected by the concentration of H3BO3. The diameter and thickness of ZnO nanotubes decreases as the composition of H3BO3 increases. The DSSC utilizing ZnO nanotubes synthesized at 2 wt. % H3BO3 performs the highest JSC and η of 2.67 mA cm−2 and 0.29%, respectively. The highest performance of the device is due to the highest optical absorption of ZnO nanotubes sample and lowest charge interfacial resistance.

Effect of Plating Additives on Microstructure and Properties of Electrodeposited Ni-Fe Alloy Thin Film

With the evolving technology, the frame mounted design of electronic components has increasingly become high-density, which leads to the electronic elements that are inevitably vulnerable to electromagnetic interference and then affect other electronic products’ functions. The solution is to use well conductive material that operates the shielding process. The material includes metals and conductive polymers which are common sources of the protective materials in dealing with the main conductive surface. Although this masking method has been widely recognized, several problems are still observed in practice, including the vulnerability to scaling, abrasion, corrosion and process load. In this study, we adopt Fe-Ni alloy film as the shielding material and manufacture it by electroplating. We intend to explore the effectiveness of changing the plating bath composition, plating parameter and plating additives on structural strength and magnetic properties of the Fe-Ni alloy film. Different proportions of nickel and iron ion concentration and content of H3BO3 cause different proportions of electrodeposited elements in the film. And the higher content of nickel ion will have higher permeability. In magnetic electroplating, plating additives play an important role. The findings suggest that various additives lead to different crystalline orientations, grain sizes, surface roughness. A strong correlation is also shown between the observed structural changes and the changes in the magnetic properties, such as permeability. Additionally, anti-corrosion is a significant issue. We can improve the corrosion problem by doping little element such as Boron in the film, obtain the corrosion potential and corrosion current by Tafel analysis. The ultimate goal of the study is to meet the requirements of electronic industry in manufacturing high permeability and optimum corrosion resistance for shielding material Fe-Ni alloy film.

Study on the emission properties of Sr2MgSi2O7:Eu,Dy for luminous fiber application

Rare earth long afterglow phosphors Sr2MgSi2O7:Eu2+,Dy3+ was synthesized by a modified solid-state reaction using H3BO3 as auxiliary reagents. In order to promote the emission properties of Sr2MgSi2O7:Eu2+,Dy3+, samples of Sr2MgSi2O7:Eu2+,Dy3+ were prepared and the effect of manufacturing elements including the concentration of H3BO3 and environmental factor of calcining temperature, concentration of Eu2+ and Dy3+ ions, external environmental factors of applications such as fiber-forming polymer as well as the addition of Ca2+ ion on its emission property were investigated through evaluating their emission spectra. The results showed that the molar ratio of the Eu2+ ions and Dy3+ ions, the amount of doping H3BO3, calcining temperature and fiber-forming polymer had little effect on the position of the emission peak and the shape in the luminescence, but greatly influenced the emission intensity of luminescent materials. The effect of Ca2+ ion doping was further studied. Ca2+ influenced not only the intensity but also the wavelength of emission and spectra of the emission peak shifted to longer wavelength as the concentration of Ca2+ increased.

Hydrogen Production from Sodium Borohydride in Boric Acid-water Mixtures

Borohydride, which reacts slowly with water, is developed as hydrogen production and storage options. The reaction is significantly accelerated by the rise of temperature or by the addition of acidic substances. Boric acid (H3BO3) can be used as an alternative to water for the hydrogen production in the hydrolysis of sodium borohydride (NaBH4). The effect of H3BO3 and NaBH4–H3BO3 molar ratios was studied at 30, 40, 50, 60, and 80°C on the hydrogen production of NaBH4. All of these results show that H3BO3 is a relatively green acid compound for hydrogen generation from NaBH4 and the H3BO3-water-NaBH4 system being quite simple for single-use applications. It was found that the reaction between H3BO3 and NaBH4 complied with a second order kinetics rate with 0.5 reaction orders versus NaBH4 concentration and 1.5 orders versus H3BO3 concentration, and the activation energy for conversion was calculated as 18.01 kJ mol−1.