2O3 Composites Research Articles

Physical and chemical characteristics and activity of nickel-modified cobalt-iron-containing catalysts in the reaction of dry reforming of methane

In the process of dry reforming of methane (DRM), the activity of low-percentage catalysts based on cobalt and iron oxides and their modification with nickel oxide was studied. It has been established that the addition of nickel oxide into the Fe2O3/γ-Al2O3 catalyst increases the degree of methane conversion from 14 to 89%, and also increases the yield of target reaction products H2 to 43.0 vol.%, CO to 46.1 vol.% at 850 °C. On a Co3О4-NiО/γ-Al2O3 catalyst at 850 °C, methane conversion reaches to 88.1%, the yield of H2 and CO is 44.8%. TPR-H2 analyzes showed that the introduction of nickel oxide into Fe2O3/γ-Al2O3 composition, in contrast to the Co3O4/γ-Al2O3 catalyst, the temperature peaks of Fe2O3-NiО/γ-Al2O3, reduction shift towards lower temperatures and weaken the interaction of metals with the support - γ-Al2O3 and thereby the amount of active reduced particles of iron and nickel oxides increases, which ensures good catalytic activity of Fe2O3-NiО/γ-Al2O3. According to the XRD results, spinel-like form - NiFe2O4, NiAl2O4 and CoAl2O4, also phase as Fe2O3 were obtained on the Fe2O3-NiО/γ-Al2O3 catalyst. This indicates that the developed catalysts form new phases that are active at high temperatures to produce synthesis gas in reduction-oxidation processes during the DRM reaction.

Electrical and UV-sensing performance of N-doped-Ba(Ti,Zr,Mo,Hf,Ta)O3-dielectric and ZnSnO-channel-based flexible thin-film transistors

Flexible thin-film transistors (TFTs) based on N-doped Ba(Ti,Zr,Mo,Hf,Ta)O3 dielectric and ZnSnO channel show high electrical and UV-sensing performance. The optimal N-doped Ba(Ti,Zr,Mo,Hf,Ta)O3 compositions with low equivalent oxide thicknesses (≈2 nm) and high-entropy (configurational entropy ≈ 1.59 R) are efficiently determined from a wide composition space (library). The film library is patterned to 450 metal–insulator-metal stacks, revealing dielectric constants ≈ 262–322 and loss (tan δ) ≈ 0.01–0.30 for the N-doped Ba(Ti,Zr,Mo,Hf,Ta)O3 at 1 kHz. The library is further integrated to 63 TFTs, and the promising ones exhibit the remarkable parameters: current on/off ratio of 108, threshold voltage (VT) of 0.02 V, saturation field-effect mobility of ≈76 cm2⋅V−1⋅s−1, and subthreshold swing of 0.062 V dec−1. The devices also exhibit desirable long-term stability for up to five months and perform reliably with small or negligible changes in VT and drain-source current under various gate-bias stress and temperature conditions. Furthermore, the TFT-based ultraviolet (253 nm) detector demonstrates impressive sensitivity (≈ 2 × 106) and responsibility (≈ 1171.9 A W−1). There is no substantial degradation in electrical or sensing characteristics under various levels of deformation. Charge transport in constructed energy band diagrams is used to elucidate the observed remarkable performance.

Construction of magnetic Fe2O3-Decorated electroactive Poly(amic acid) composites as recyclable Catalysts: Increased loading of gold Nanoparticles, Controlled Size, and Accelerated catalytic reduction of 4-Nitrophenol

Nanocomposites are widely used in heterogeneous catalysts in the field of water treatment, which exhibit controllable structural advantages and synergistic effects between their components further enhancing catalytic activity. In the current research, we developed the Au nanoparticles immobilized magnetic γ-Fe2O3/Electroactive Poly (amic acid) composite (6Au/EPAA-Fe2O3) prepared by using the in-situ redox reaction strategy. Sundry techniques such as FT-IR, XRD, TGA, SEM/HR-TEM, CV, and XPS analysis have been applied to explain the chemical structure and morphology of as-synthesized composites. The catalytic performance of the catalyst during the reduction of 4-nitrophenol using NaBH4 as a hydrogen donor was assessed in an aqueous medium at room temperature. Attractively, 6Au/EPAA-Fe2O3 composite exhibits superior catalytic performance, which completes the reduction of 4-NP within the 50 s. The pseudo-first-order kinetic rate constants were estimated as 3.0 × 10-2 s−1 for the reduction of 4-NP. Furthermore, the 6Au/EPAA-Fe2O3 composite has excellent stability and reproducibility of 10 consecutive runs by using an external magnet without loss of catalytic activity.

Fe2O3-decorated multiwall carbon nanotube composites for boosted microwave absorption

Developing microwave absorption (MA) materials with a strong absorption ability over a wide bandwidth through a simple and environmentally friendly approach remains a tremendous challenge. Herein, we propose to use an Fe3+–tannic acid framework to assist the dispersion of multi-walled carbon nanotubes (MWCNTs) and successfully prepare MWCNTs/porous carbon/α-Fe2O3 composites through freeze-drying and subsequent heat treatment. The dielectric properties and MA performance can be regulated by the heat treatment temperature, which leads to tunable crystalline structure, composition, and graphitization degree of MWCNTs. Consequently, the MWCNTs/porous carbon/α-Fe2O3 composite heat-treated at 300 °C exhibits a high reflection loss (RL) of −58.9 dB and an effective absorption bandwidth (5.28 GHz) with a matched thickness of 2.26 mm at a filler proportion of only 5 wt%, and the related frequency bandwidth with RL below -10 dB reaches 14.3 GHz at a thickness of 2–5 mm. In conclusion,the balance between conduction and polarization loss endows the composite with excellent impedance matching and boosting MA performance. This study offers a guideline for fabricating excellent MA materials through a simple, environmentally friendly method.

Interfacial engineering of (Ce,Zr)O2 composite barrier layers for enhancing the durability of solid oxide fuel cells

The dense GdxCe1-xO2 (GDC) barrier layer can't prevent the diffusion of small amounts of Sr through grain boundaries. Recent studies indicate that the (Ce,Zr)O2 composite, placed between GDC and YSZ (Y2O3 stabilized ZrO2) electrolyte, can effectively suppress SrZrO3 formation. In this study, we successfully designed and prepared an anode-supported solid oxide fuel cell (SOFC) with a dense GDC/IDL (interdiffusion layer) composite barrier layer, demonstrates excellent inhibition of elemental diffusion through grain boundaries. Compared with the cell with a single dense GDC barrier layer, the cell with GDC/IDL composite barrier layer exhibits largely improved durability, with a two-fold decreased degradation rate of 2.7 %/kh, operated under constant current density of 400 mA/cm2 at 720 °C. The cell with GDC/IDL barrier layer presents decreased initial performances, with lager Rohm of 0.085 Ω cm2 than 0.075 Ω cm2, and smaller initial Pmax of 0.905 W/cm2 than 1.019 W/cm2 at 750 °C. However, the cell performance surpasses the cell with single GDC barrier after 230 h. Thus, we obtain a new strategy to achieve improved cell durability by sacrificing the cell's initial performance. The in-situ constructed continuous and dense GDC/IDL composite optimizes the electrolyte/cathode interface while maintaining decent electrochemical performance, providing a new horizon to design and prepare high performance and durable SOFCs.

A novel Al/BiCl3/γ-Al2O3 composite for small-sized fuel cell: Fabrication, performance and mechanisms

Small-sized fuel cell is an ideal and promising power source for portable devices due to its long-term electricity supply and free of CO2 emission. However, its commercialization is obstructed by reliable hydrogen source, which should be non-corrosiveness, as compact as possible, stable and controllable high purity hydrogen supply. In this study, a novel in situ hydrogen production material Al/BiCl3/γ-Al2O3 composite is synthesized, which exhibits high hydrogen yield, fast hydrogen production rate and outstanding storage stability. The hydrogen production performance of Al/BiCl3/γ-Al2O3 can be adjusted by changing BiCl3:γ-Al2O3 weight ratio, additive content and milling time. XRD and SEM results indicate that surface cracks, active surface and metal Bi produced in fabrication process lead to the high hydrolysis activity of Al/BiCl3/γ-Al2O3. Mechanism analyses reveal that hydrogen production process is the results of pitting, microgalvanic effect and catalytic effect. Taking into account hydrogen production performance, capacity and cost, Al/5 wt%BiCl3/5 wt%γ-Al2O3 milled for 2 h is a potential hydrogen production material, which can in situ supply hydrogen for small-sized fuel cell.

Electrochemical investigations of chitosan/ZrO2-Bi2O3 composite for advanced energy and environmental applications

Energy needs are on the rise, and the need for effective corrosion resistance measures are also vital to meet the requirements prevailing in society. A multifunctional Chitosan/ZrO2-Bi2O3 composite is synthesized, keeping electrochemical analysis of energy and environmental applications in mind. Various physicochemical methods confirm the impact of integrating ZrO2-Bi2O3 into chitosan, resulting in improved efficacy across applications. The electrocatalytic supercapacitance, hydrogen evolution reaction, and corrosion inhibition studies are carried out to evaluate the efficiency of the synthesized composite. The composite shows a specific capacitance of 636.5 F/g, ensuring the effective utility for supercapacitance applications. The lower overpotential of 135.2 mV is shown by the composite in the electrocatalytic hydrogen evolution reaction. The synthesized composite also shows 96.2 % efficacy in corrosion inhibition studies. The studies conducted demonstrate the increased effectiveness of chitosan when combined with bimetal oxide. The chitosan composite is therefore a competent catalyst for energy and environmental applications.

Investigating and predicting tribological characteristics of AZ31 alloy composites reinforced with nano-Al2O3 and micro-Sn particles: a comparative analysis using CCD-RSM and ANN models

In this research, the central composite-based response surface methodology was adopted to select the dominant optimal input factors on wear behaviour and coefficient of friction of an AZ31-microtin/2 wt% nano-Al2O3 composite prepared through a stir casting process with different wt% of Sn. The input factors, such as wt% of Sn reinforcement, sliding distance, sliding speed, and applied load, were selected to determine their significant effects on the coefficient of friction and wear behaviour with 30 trial runs. Analysis of variance (ANOVA) results indicated that Sn reinforcement plays a significant role in the wear behaviour of the nanocomposites, followed by applied load and sliding distance. In addition, an enhancement in wear resistance was witnessed by the addition of Sn reinforcement with AZ31/nano-Al2O3 composites. The optimal process parameters as per the desirability approach were found to be a weight percentage of Sn: 8%, load: 20 N, sliding speed: 2 m s−1, and sliding distance: 1000 m. According to the ANN results, the predicted data is perfectly acceptable with the actual experimental response value. The R values for the training, validation, and testing phases are 0.96166, 0.96801, and 0.98914 for COF, and 0.97688, 0.99247, and 0.99331 for wear rate, indicating a robust correlation between predicted and actual values. The worn-out pin samples were used to examine the worn surface morphology and analyze the wear mechanism.

Fabrication of Bi0.90Sm0.1Fe0.97Cr0.03O3@PANI core-shell and improvement of its photocatalyst properties

Bi0.90Sm0.1Fe0.97Cr0.03O3@PANI core-shell structures were made by a two-step method, first, bismuth ferrite nanoparticles by hydrothermal method and then, aniline core-shell by co-precipitation method. The bismuth ferrite (BFO) XRD pattern showed no impurities of Sm, Cr, or their compounds in the samples, indicating that Sm+3 and Cr+3 had been replaced in the BFO structure. The XRD pattern of the Bi0.90Sm0.1Fe0.97Cr0.03O3@PANI core-shell shows all peaks of Bi0.90Sm0.1Fe0.97Cr0.03O3 composition with lower intensity, as a result, the Bi0.90Sm0.1Fe0.97Cr0.03O3 composition is phase single. This lower intensity is attributed to the presence of amorphous polyaniline in the core-shell structure. Since there is in the FT-IR spectrum of the Bi0.90Sm0.1Fe0.97Cr0.03O3@PANI core-shell, characteristic peaks of both polyaniline and bismuth ferrite simultaneously so, the FT-IR spectrum of the Bi0.90Sm0.1Fe0.97Cr0.03O3@PANI core-shell is a perovskite structure. The synthesized samples exhibit weak magnetic properties and behave as a paramagnetic material. The absorption capability of core-shell compared to core nanoparticles has increased in the visible region, and this enhancement is attributed to the influence of the presence of polyaniline. All the peaks in the UV–visible absorption spectrum characterize the nano-sized bismuth ferrite and polyaniline in the UV–visible spectrum of the core-shell. The intensity of the photoluminescence spectrum in the doped sample is significantly higher compared to the core-shell sample. This indicates a much faster recombination rate in the doped nanoparticles compared to the core-shell nanocomposite. The doping of the core with Cr and Sm elements, as well as the coating of the core with a polymeric shell, has led to an increase in the degradation rate of the red dye. We also found that shell thickness plays a vital role in dye degradation efficiency and photocatalytic performance. The Bi0.90Sm0.1Fe0.97Cr0.03O3@PANI core-shell exhibits significant photocatalytic activity under visible light. The photocatalytic studies show that the best sample is Bi0.9Sm0.1Fe0.97Cr0.03O3@PANI core-shell with aniline concentration of 0.2 mL and a pH = 2 which was able to destroy 100 % of Congo red dye molecules.

Enhanced structural, vibrational, and dielectric properties of (Ba0·95Ca0.05) (Ti0.95Zr0.05)1-x(Zn1/3Nb2/3)xO3 ceramics

The (Ba0·95Ca0.05) (Ti0·95Zr0.05)1-x(Zn1/3Nb2/3)xO3 BCZTxZN compounds, were created using the widely adopted solid-state method. To assess the impact of (Zn, Nb: ZN) co-substitution ions we studied the structural, vibrational, and dielectric characteristics of BCZT. The phase purity was validated by conducting Rietveld refinement of XRD data, indicating the coexistence of orthorhombic and tetragonal phases at ambient temperature in the (Ba0·95Ca0.05) (Ti0·95Zr0.05)0.975(Zn1/3Nb2/3)0.025O3 (BCZT25ZN) composition. Furthermore, Raman spectroscopy confirmed the observed transitions. The presence of Zn2+ and Nb5+ ions resulted in a decrease in cell parameters and cell volume. The real part of the dielectric constant and the tangent loss (tan δ) exhibited values of approximately 3380 and 0.031, respectively, for the sample (Ba0·95Ca0.05)(Ti0·95Zr0.05)0.95(Zn1/3Nb2/3)0.05O3 (BCZT50ZN), obtained by substituting ZN in Ba0·95Ca0·05Ti0·95Zr0·05O3. Incorporation of ZN into Ba0·95Ca0·05Ti0·95Zr0·05O3 presents promising prospects for using the material in various device applications, including energy storage capacitors, sensors, and actuators.

Microstructure and mechanical properties of the (Al1/6Cr1/6Nb1/6Ta1/6Ti1/3)O2 high-entropy ceramic coating prepared by laser cladding

The (Al1/6Cr1/6Nb1/6Ta1/6Ti1/3)O2 high-entropy ceramic coating was fabricated by laser cladding in this study. For the continue and dense coating structure, there were pre-treatments including the squash presetting of feedstock powders and the deposition of Al2O3-TiO2 coating on steel substrate by atmospheric plasma spray. The XRD technology was conducted for investigating the phase transitions during the fabrication of (Al1/6Cr1/6Nb1/6Ta1/6Ti1/3)O2 coating. The SEM, EDS technologies and nano-indenter were operated for evaluating the microstructure, composition and mechanical properties of the (Al1/6Cr1/6Nb1/6Ta1/6Ti1/3)O2 coating. The results showed that the feedstocks with various structures were successfully transformed into the (Al1/6Cr1/6Nb1/6Ta1/6Ti1/3)O2 high-entropy ceramic with rutile structure as well as the formation of intermediate products in similar structures. The (Al1/6Cr1/6Nb1/6Ta1/6Ti1/3)O2 coating had a tight combination with the Al2O3-TiO2 coating and showed a thick and compact structure, which included various dendritic crystal structures composed of segregated Al2O3. The (Al1/6Cr1/6Nb1/6Ta1/6Ti1/3)O2 coating exhibited a high level of hardness (13.58 ± 2.05 GPa) and elastic modulus (275.24 ± 32.26 GPa).

Effect of Ni-Doping on Seebeck Coefficient of LaCoO<sub>3</sub> System

The aim of this study is discussing the results achieved on undoped and Ni-doped bulk LaCoO3 samples synthesized by solid-state reaction. The crystal structures of the samples were analyzed by x – ray diffraction (XRD) and Rietveld refinement of the XRD patterns was used to test the quality of the samples, the results of this procedure confirmed a single phase of LaCo1-xNixO3 for (x=0 and 0.05) with rhombohedral crystal structure (space group :). The main interest in this class of materials is the possibility of improving the values of Seebeck coefficient and electrical resistivity through chemical doping. The Seebeck coefficient and electrical resistivity were investigated from room temperature (RT) to 450 K, near RT the LaCoO3 system showed a large negative Seebeck coefficient, but it changed to positive value with increasing temperature while the LaCo0.95Ni0.05O3 composition showed a positive Seebeck coefficient throughout all the temperature range. Hence, within this study the Ni substitution led to decrease the electrical resistivity of the samples to one order of magnitude as a result of the partial substitution of Co3+ in LaCoO3 by Ni2+. LaCoO3 was chosen for this thermoelectric test because cobalt oxides have extensive applications.

Amorphous RhOx decorated black indium oxide for rapid and flexible NO2 detection at room temperature

This paper focuses on the preparation and characterization of a composite material made from rhodium oxide amorphous-decorated black indium oxide (RhOx/B-In2O3) for use in MEMS gas sensors. The sensors were utilized for the detection of NO2 gas at room temperature, and the results demonstrate that the RhOx/B-In2O3 sensor exhibits excellent gas selectivity, high response, and extremely short response/recovery times (8 s/17 s) to 5 ppm NO2 gas at room temperature. Additionally, a flexible NO2 gas sensor based on the optimized RhOx/B-In2O3 composite was fabricated to expand its application. One of the unique aspects of the RhOx/B-In2O3 material is the existence of defects, which allows for greater adsorption of NO2 gas. This feature contributes to the increased gas selectivity seen in the B-In2O3 material as compared with common In2O3. The chemical sensitization and electron-rich properties of amorphous RhOx further enhance the gas-sensing performance of the material by reducing the reaction activation energy and increasing surface-adsorbed oxygen. Overall, the results demonstrate the potential of the RhOx/B-In2O3 composite material for use in advanced gas-sensing technologies.

Investigation of the Positive Temperature Coefficient Resistivity of Nb-Doped Ba0.55Sr0.45TiO3 Ceramics

The demands of low-Curie-temperature (~−10 °C) positive temperature coefficient (PTC) thermistors are increasing in advanced precision integrated circuits and other industries. In this paper, the Nb-doped Ba0.55Sr0.45TiO3(BST)-based PTC resistivity materials are reported. The effects of the sintering process, especially the cooling rate on the PTC properties of the material, are investigated. The results indicate that the Ba0.55Sr0.45Ti0.9985Nb0.0015O3 composition of the prepared PTC ceramics demonstrates promising PTC characteristics. These include a Curie temperature as low as −13 °C, a high temperature coefficient of 0.296 at −3.4 °C, a large enough resistivity change of 3.1 over a narrow phase transition temperature range of approximately 38 °C, and moderate resistivity below the Curie temperature. Such properties suggest that the Ba0.55Sr0.45Ti0.9985Nb0.0015O3 ceramics are likely suitable for use in thermal management systems designed for low-temperature control.

Mӧssbauer and dielectric studies of Bi0.6Nd0.4Fe0.5M0.5O3 (M – Mn, Cr) solid solution ceramics fabricated by a high-pressure synthesis

Bi0.6Nd0.4Fe0.5M0.5O3 (M – Mn, Cr) compositions with perovskite structure were fabricated by a high-pressure synthesis. Mӧssbauer studies have shown that doping with Nd does not change substantially Neel temperature values of Bi0.6Nd0.4 Fe0.5M0.5O3 (M – Cr, Mn) compositions. However, the Fe3+ and Mn3+ ions seem to be inhomogeneously distributed in the crystal lattice and form Fe-poor and Fe-rich regions. Similar result was obtained by us earlier for Bi(Fe1-xCrx)O3 solid solution. Both compositions studied exhibit a giant dielectric response in a wide temperature range. The giant dielectric response seems to be due to the relaxation of electrons or polarons trapped by oxygen vacancies.

Huge redshift of absorption edge in a novel Z-type Bi2Sn2O7/α-Bi2O3 junction for highly efficiently visible light degradation of norfloxacin and bisphenol AF

Heterojunction was mainly used to realize the separation of charge carrier in current studies, but it did not bring about any other effect. In this paper, Bi2Sn2O7 was introduced into α-Bi2O3 to construct a direct Z-type Bi2Sn2O7/α-Bi2O3 heterojunction. It not only accelerated the rapid separation of electrons and holes, but also induced a huge redshift of absorption edge to enlarge the visible light absorption range. Such result led into the optimal sample being able to degrade 95% of norfloxacin and 92% of bisphenol AF for 90 min of visible light irradiation. Under the same testing conditions, the removal efficiency of these two pollutants in the drinking water also attained 94% and 90% to demonstrate a good application. Moreover, the cycling test results indicated that the Bi2Sn2O7/α-Bi2O3 could be sustainably utilized. The electrons, holes, superoxide radical (•O2-) and hydroxyl radical (•OH) were the active substances in the process of degradation. The numbers of the Escherichia coli were 0.69×106 CFU/mL and 0.75×106 CFU/mL in the solutions after degradation to denote non-toxicity of the final products. Thus the Bi2Sn2O7/α-Bi2O3 composite could be applied in purification of various waste waters.

Ionic liquid modified PVDF/BCZT nanocomposites for space charge induced mechanical energy harvesting performance

Mechanical energy harvesting performances of poly(vinylidene fluoride) (PVDF) based composites are most often correlated with their polar phase and the individual piezoelectricity of the used filler materials. Here we show that the significant enhancement of space charge polarization of the said composites can play the key dominant role in determining their mechanical energy harvesting performance regardless of their polar phase and individual piezoelectricity of the used fillers. For this purpose, ionic liquid has been incorporated into PVDF/0.5(Ba0.7Ca0.3)TiO3–0.5Ba(Ti0.8Zr0.2)O3 (BCZT) composites which led to a huge enhancement in space charge polarization. The gradual addition of ionic liquid into 10 wt% BCZT loaded PVDF (PBCZT) has helped in extraordinarily enhancing the conductivity gradually which has confirmed the huge enhancement of space charge polarization. However, after a certain limit of ionic liquid addition, the polar phase of the composite films is decreased. Despite this, the output voltages from the piezoelectric and piezo-tribo hybrid nanogenerators (PENGs and HNGs, respectively) fabricated by using the developed films have been found to be increased gradually with the increase in the ionic liquid amount in PBCZT composite. As the amount of BCZT filler was kept fixed for all the films, this result has confirmed the key role of space charge polarization of PVDF-based composites in determining their mechanical energy harvesting performances compared to the effect of polar phase and individual piezoelectricity of filler. The optimized PENG and HNG devices have shown the output voltage as high as 52 and 167 V, respectively, with power densities ∼85 and 152 μW cm−2 which predicted their excellent usability in real life energy conversion devices. This work also shows that the effect of extraordinarily enhanced space charge polarization is effective in improving the performance of all types of mechanical energy harvesting devices regardless of their mechanisms (piezoelectric or hybrid).

Development of Composite Materials Using Magnesium Matrix with Variations in the Addition of Volume Fractions of Nano-Al2O3 Reinforcement Results of the Stir Casting Method

Magnesium matrix composites were developed as a form of material selection that can save fuel use due to excess magnesium, which has very low specific gravity and still has good mechanical properties. In this study, a magnesium matrix composite with nano-Al2O3 reinforcement was successfully fabricated using the stir casting method. When compared with magnesium monolithic, the addition of nano-Al2O3 particles of 0.05, 0.10, 0.15, 0.20, and 0.25 %Vf in magnesium composite casting was investigated to improve the mechanical properties of Mg/nano-Al2O3 composites. Magnesium composites with 0.20% Vf reinforcement were found to be the best composition of impact price, wear rate, density, and porosity. This is because the more reinforcement given, the more mechanical properties increase, but the agglomeration tendency of nano-Al2O3 particles is higher so that at a composition of 0.25 %Vf, there is a mechanism anomaly because the reinforcement carried out is less homogeneous. In addition to the number of amplifiers, the improvement of mechanical properties is influenced by the fabrication process, i.e. stir casting. This study uses chemical characterization of OES, EDS, and XRD, hard damage, impact, wear, density and porosity testing, and metallographic observations using OM and SEM.

Precursor influence on the raman spectrum of KNNLiTaLa0.01 prepared by two different methods

This work presents a study of ceramics with the (K0.44Na0.52Li0.04)0.97La0.01Nb0.9Ta0.1O3 composition through their Raman spectra. In the previous studies [1], this particular composition has shown good permittivity and piezoelectric parameter values that justify a deeper investigation. Two sets of samples of these ceramic compounds were prepared using different methods. The first set was prepared using a classical solid-state reaction of oxides and carbonates, as described in Ref. 2. The second set was prepared using the NaNbO3 as a precursor. The Raman spectra of the samples obtained by the direct ceramic method consisted of 4 modes. In contrast, the spectra of the samples obtained using the precursor showed a shift of the wavenumber of the A1g(ν1) mode peak towards lower values and consisted of six modes with the appearance of two additional IR modes, F1u(ν3) and F2g(ν4). Notably, the use of the precursor preparation route led to important improvements resulting in a more straightforward method than that of Saito et al. [3].

Analisis Kinerja Pengolahan Biogas di PT. Mitra Puding Mas Kecamatan Putri Hijau Kabupaten Bengkulu Utara Provinsi Bengkulu

PT. Mitra Puding Mas is one of the oil palm fruit processing factories in Bengkulu Province. POME palm oil mill effluent is the largest waste generated from the palm oil production process. The largest components contained in biogas are CH4 (50 % – 75 %) and CO2 (24% - 45 %) as well as several percent, nitrogen and hydrogen sulfide. The purpose of this study was to determine the composition of biogas CH4, O2, CO2 and H2S as well as the factors that affect the performance of biogas processing production at PT Mitra Puding Mas. Processing performance was obtained by using secondary data collection methods and literature study, while the factors influencing performance were obtained through interviews and observations. The results of the analysis of the performance of the biogas processing process, CH4 (53.6%), CO2 (36.18%), O2 (1.14%) and H2S (1.92 ppm) were categorized according to the standard composition of biogas liquid waste from palm oil. Factors that affect the performance of biogas processing are categorized very well, in the human aspect, namely the employees are skilled and expert in biogas management, in the raw material aspect, namely the use of palm oil or POME liquid waste as biogas raw material, in the method aspect, namely work instructions according to the SOP before and during the production process; on the machine aspect that is always checked regularly or periodically to avoid damage.