X-ray Diffraction Diffraction Peaks Research Articles

Synergistic effects of liquid phase sintering and B-site substitution to enhance proton conductivity of BaZr0.1Ce0.7Y0.1Yb0.1O3-δ for protonic ceramic fuel cell

This paper is dedicated to improving the sintering and conductivity of BaZr0.1Ce0.7Y0.1Yb0.1O3-δ (BZCYYb) by adding ZnO–CuO dual-sintering aids. The synergistic effects of liquid-sintering of Zn and B-site substitution of Cu on the sinterability and proton conductivity of BZCYYb are systematically investigated. X-ray diffraction (XRD) analysis of BZCYYb after addition of ZnO–CuO (BZCYYb-Zn-Cu) confirms the complete perovskite phase formation without any secondary phase. The substitution of Ce4+ (0.87 Å) with Zn2+ (0.74 Å) or Cu2+ (0.73 Å) induces a shift in XRD diffraction peak to higher angle due to a decrease in lattice constant. Energy dispersive X-ray spectroscopy analysis indicate a distinct distribution of Zn primarily at the grain boundaries, while Cu is predominantly located within the grains of BZCYYb-Zn-Cu. The addition of ZnO–CuO into BZCYYb results in a denser microstructure with larger average grain size. Furthermore, the substitution of Ce4+ by Cu2+ increases the concentration of oxygen vacancies and reduces activation energy. For BZCYYb-Zn-Cu, the proton conductivity reaches 4.52 × 10−2 S/cm at 750 °C, approximately 3 times higher than that of BZCYYb. This enhancement can be attributed to the synergistic effects of larger average grain size resulting from liquid phase sintering of Zn, low active energy, and high concentration of oxygen vacancies arising from Cu B-site substitution. BZCYYb-Zn-Cu is used as the electrolyte for anode support SOFC, and the single cell exhibits remarkable electrochemical performance and excellent stability in H2 fuel. This research establishes a crucial theoretical foundation for the preparation and performance evaluation for large-size protonic ceramic cell.

The Effect of Oxalic Acid and Citric Acid on the Modification of Wollastonite Surface.

The modification mechanism of low-molecular-weight organic acids on a single-chain silicate mineral (wollastonite) was investigated through a leaching method. Solid and liquid samples were analyzed using atomic absorption spectrophotometer (AAS), X-ray diffraction (XRD), scanning electron microscope (SEM), and Fourier-transform infrared spectroscopy (FTIR). After 720 h of reaction, the results revealed that the dissolution concentration of Si (2200 μmol/L) in citric acid solution is more than that (1950 μmol/L) in oxalic acid. In the composite acids (citric acid and oxalic acid), the dissolution concentration of Si release from wollastonite reached the maximum value of 3304 μmol/L. The dissolution data of Si in wollastonite were fittingly described by the parabolic equation (Ct = a + bt1/2), with the highest correlation coefficients (R2 > 0.993), in the presence of the low-molecular-weight organic acids. The dissolution data suggested that the dissolution reaction process of Si was consistent with the diffusion-controlled model. Citric acid exhibited a higher affinity for attacking the (200) surface, while oxalic acid was prone to dissolve the (002) crystal face. The synergistic effects of oxalic acid and citric acid led to the weakening of the XRD diffraction peak intensity of wollastonite. When exposed to composite acids, the surface of wollastonite was covered with insoluble reactants that restricted the substance diffusion and hindered the reaction. This study offers valuable theoretical insights into the modification or activation of wollastonite by composite low-molecular-weight organic acids.

Thermal decomposition mechanism and kinetics of bastnaesite in suspension roasting process: A comparative study in N2 and air atmospheres

To investigate the thermal decomposition behavior and reaction kinetics of bastnaesite in suspension roasting, the gas and solid products of bastnaesite roasted in N2 and air atmospheres were examined using a gas analyzer, X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectrometry (EDS). Subsequently, the kinetic parameters of bastnaesite in the suspension roasting process were derived and calculated using the isothermal method. The results show that the decomposition product of bastnaesite in N2 is CeOF. However, once the roasting temperature exceeds 600 °C, CO is generated in addition to CO2, and all the XRD diffraction peaks of CeOF are shifted to the right, indicating that CO2 can oxidize CeOF and lead to the transformation of Ce(III) into Ce(IV). When roasted in air, the decomposition product CeOF can be completely converted to CeF3 and Ce7O12 as it easily oxidizes. Additionally, the reaction rate of bastnaesite in air is higher than that of N2, and the starting reaction temperature is lower than that of N2. A large number of irregular cracks and holes appear on the surface of solid-phase products following suspension roasting, which are due to the thermal decomposition of bastnaesite that produces CO2 as well as the reconstruction of the lattice of the solid-phase products. The reaction kinetic model of bastnaesite roasted in N2 (temperature range 600–750 °C) and air (temperature range 500–575 °C) conforms to the A3/2 model with the mechanism function G(α)=–ln(1–α)2/3, and the reaction activation energy is 59.78 kJ/mol and lnA is 1.65 s−1 in N2 atmosphere. In air, the reaction activation energy is 100.30 kJ/mol and lnA is 9.63 s−1.

Hydrogen catalytic performance of hybrid Fe3O4/FeS2/g-C3N4 nanocomposite structures

In this work, Fe3O4/FeS2/g-C3N4 nanocomposites were developed for catalytic hydrogen generation from sodium borohydride. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and environmental scanning electron microscopy (ESEM) were used to analyze these nanocomposites. The XRD diffraction peaks of Fe3O4 and FeS2 cubic phase showed an average crystal size of calculation of 15 and 20 nm. ESEM micrographs showed a 2D broken up sheet structure having more edge sites. The BET surface areas for S@g-C3N4, 1.0, 2.0, and 3.0 wt% Fe3O4/FeS2 were 40, 109, 137 and 162 m2/g, respectively. Even though Fe3O4/FeS2 were incorporated into the nanosheet, the pore size was increased from 2.0 to 2.15 nm. S@g-C3N4 has an average band gap of 2.60 eV that decreased to 2.30, 2.21 and 2.18 eV at 1.0, 2.0 and 3.0 wt% of FeS2. In addition, Fe3O4/FeS2/g-C3N4 nanosheets showed an emission band at 460 nm. Moreover, the intensity of this band decreased as the content of Fe3O4/FeS2 reached 3.0 wt%. The rate of hydrogen production is accelerated as the percentage of Fe3O4/FeS2 increased from 1.0 to 3.0 wt%. The sample 3.0 wt% Fe3O4/FeS2 showed the best rate of hydrogen production (8480 mL/g·min).

Effect of Heat Treatment on Microstructure and Tribological Properties of Laser Cladding CeO2/Ni60 Composite Coating on 35CrMoV Steel

A Ni60 cladding layer with addition of 6.0% CeO2 was prepared on 35CrMoV steel by laser cladding technology. The prepared sample was placed at 500 °C, 600 °C and 700 °C for 60 min to explore the effects of heat treatment on the tribological properties of the composite coating. The microstructure, phase composition, microhardness and tribological properties of the composite coating were characterized by optical microscopy and scanning electron microscopy (SEM), X-ray diffraction (XRD), micro-Vickers hardness tester and MicroXAM-800 optical surface photometer, respectively. According to the above experimental results analysis, the main components of 6.0% CeO2/Ni60 cladding layer are γ-(Fe,Ni),Cr7C3,Cr23C6,CrB, CrFeB and Cr2Ni3. By calculating the FWHM value and the left shift of the XRD diffraction peak, it is found that the coating grains are remarkably refined and the microstructure uniformity is significantly improved under the condition of heat treatment at 500 °C. The experimental results show that the Ni60 composite coating with 6.0% CeO2 has the best friction and wear performance at 500 °C. The wearing quality of the composite coating at 500 °C was reduced by 43%.

The construction of three-dimensional CdIn2S4/MoS2 composite materials for efficient hydrogen production

In this study, CdIn2S4/MoS2 composite structure was prepared by a simple two-step hydrothermal synthesis method, and the CdIn2S4/MoS2 composite structure samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and UV–vis diffuse reflectance spectroscopy (UV–vis). Due to the effective loading of MoS2 on the surface of CdIn2S4 particles, the photocatalytic performance of CdIn2S4/MoS2 composite material is significantly improved under visible light irradiation (λ = 420 nm), which indicating the effective inhibit the recombination of photogenerated electron holes. Meanwhile, the visible light response of CdIn2S4 is increased and the life of photoexcitation carrier is prolonged. The CdIn2S4/MoS2 (sample 2CM) composite sample with mole content of 9% has the highest catalytic hydrogen production activity, and its hydrogen production rate is 293 μmol h−1 g−1, which is more than 3 times that of sample C. After 4 cycles of photocatalytic experiments, the photocatalytic activity is still stable, and the XRD diffraction peak does not appear obvious shift, which provides a new way for the design and preparation of efficient and stable photocatalytic materials.

Boosting Efficient Ammonia Synthesis over Atomically Dispersed Co-Based Catalyst via the Modulation of Geometric and Electronic Structures

Boosting Efficient Ammonia Synthesis over Atomically Dispersed Co-Based Catalyst via the Modulation of Geometric and Electronic Structures

High-Performance Ru 2 P Anodic Catalyst for Alkaline Polymer Electrolyte Fuel Cells

High-Performance Ru ₂ P Anodic Catalyst for Alkaline Polymer Electrolyte Fuel Cells

Critical role of additive-induced molecular interaction on the operational stability of perovskite light-emitting diodes

Summary Despite rapid improvements in efficiency and brightness of perovskite light-emitting diodes (PeLEDs), the poor operational stability remains a critical challenge hindering their practical applications. Here, we demonstrate greatly improved operational stability of high-efficiency PeLEDs, enabled by incorporating dicarboxylic acids into the precursor for perovskite depositions. We reveal that the dicarboxylic acids efficiently eliminate reactive organic ingredients in perovskite emissive layers through an in situ amidation process, which is catalyzed by the alkaline zinc oxide substrate. The formed stable amides prohibit detrimental reactions between the perovskites and the charge injection layer underneath, stabilizing the perovskites and the interfacial contacts and ensuring the excellent operational stability of the resulting PeLEDs. Through rationally optimizing the amidation reaction in the perovskite emissive layers, we achieve efficient PeLEDs with a peak external quantum efficiency of 18.6% and a long half-life time of 682 h at 20 mA cm−2, presenting an important breakthrough in PeLEDs.

Effects of tension fatigue on the structure and properties of carbon black filled-SBR and SBR/TPI blends

Abstract The aim of this study was to explore the impact of tension fatigue on the structure and properties of filled SBR and SBR/TPI blends. The effect of tension fatigue on the dynamic properties of carbon black-filled styrene-butadiene rubber (SBR) and SBR/trans-1,4-polyisoprene (SBR/TPI) blend vulcanizates were investigated by dynamic mechanical analysis (DMA). The Mooney-Rivlin analysis of tensile stress-strain data is used for the determination of a rubber network crosslink density. The fatigue fracture surface of SBR/TPI vulcanizates was observed with a scanning electron microscopy (SEM). The crystallinity of TPI in carbon black-filled SBR/TPI (80/20) was characterized by X-ray diffraction (XRD). The results showed that the incorporation of TPI into SBR vulcanizates influences the fatigue properties of the blend vulcanizates. The blend vulcanizates showed optimum fatigue properties with 20 phr TPI. With increasing fatigue cycles, the tensile properties and crosslink density of SBR vulcanizates were decreased substantially. Compared with that of SBR vulcanizates, the tensile properties and crosslink density of SBR/TPI (80/20) blend vulcanizates changed little with the increase in fatigue cycles, and tan δ and E′ decreased gradually with the fatigue cycles. There was a sharp decrease in the E′ and tan δ curve in the temperature range of 40 ~ 60°C. The XRD diffraction peak corresponding to 3.9 Å broadened when the fatigue cycles were increased to 1 million times, and a new peak with inter-planar spacing at 7.6 and 4.7 Å appeared.

The effect of a buffer layer on the structure and the performance of cutting-tools for ZrWN films that are deposited using DCMS and HIPIMS

This paper determines the optimal settings for the deposition of ZrWN nitride films using reactive direct current magnetron sputtering (DCMS) and high-power impulse magnetron sputtering (HIPIMS), with pure Zr and W metal targets and Ar plasma and N2 reactive gases. The materials tested as buffer layers are metal tungsten (W) and tungsten nitride (WN) thin films. Using a Taguchi method, this study determines the effect of deposition parameters for the buffer layer (W DC power, substrate bias, N2/(N2+Ar) flow rate and substrate temperature) on the structural and mechanical properties, and the dry machining performance of cutting-tools for multilayer ZrWN/W and ZrWN/WN/substrates. In the confirmation runs using grey Taguchi analysis, there is an improvement of 32.31% and 13.38% in surface roughness and flank wear, respectively. The films are characterized using X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (FEI-TEM) and a nanoindenter. The TEM pattern for the ZrWN films shown corresponds to the (111), (200) and (220) planes of the face-center-cubic phase. Pretreatment of a tungsten carbide tool uses oxygen plasma etching to enhance the adhesion of the multilayer ZrWN/WN coating. Compared with coatings that are deposited using DCMS, the samples that are deposited using HIPIMS exhibit a higher film density and a smoother surface. In the HIPIMS mode, the XRD diffraction peaks of the films are sharper and more intense, which indicates an improvement in crystallinity.

The Phase and Morphology of CuInSe2 Film Prepared by One-Step electrodeposition

CuInSe2 with chalcopyrite structure has become one of the most promising photoelectric materials for its high optical absorption coefficient and conversion efficiency. Electrodeposition has the advantages of low cost and easy operation. CuInSe2 thin films were prepared by one-step electrodeposition with CuC12·2H2O, InC13, SeO2 as raw materials. Cyclic voltammetry curves of the solutions were tested by electrochemical workstation. The phases of product thin films were analyzed by X-ray diffraction (XRD) and the surface morphology was characterized by scanning electron microscope (SEM). Experimental results show that the continuous, uniform and dense CuInSe2 thin films can be obtained under conditions of deposition potential -0.5 V and sodium citrate as complexing agent with concentration of 5mmol/L. The XRD diffraction peaks of CuInSe2 thin film are corresponding to the crystal planes of (112), (220) and (312) respectively.DOI: http://dx.doi.org/10.5755/j01.ms.23.4.17447

Eco-friendly natural rubber–silver (NR–Ag) composites for photo-assisted degradation of methyl orange dye

An environmental friendly, low cost composite for the photo-assisted degradation of methyl orange (MO) is proposed. Here, natural rubber–silver (NR–Ag) composites are formed through soft thermal reduction. The characteristics of the NR–Ag composites were investigated using UV–vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The deposition of Ag on the surface of natural rubber was proven by the XRD diffraction peaks, attributed to metallic Ag and the appearance of the surface plasmon resonance of Ag, at ~ 420–460 nm in the UV–vis spectrum. The degradation of MO dye by NR–Ag composite under UV light source showed positive results for the degradation of dye even with minute amounts of Ag content. The degradation mechanism of MO involved the generation of hydroxyl radicals from the UV-irradiated NR–Ag composite by the formation of superoxide species as the important radical intermediate. Several parameters such as the Ag salt concentration and pH of the MO dye were investigated. Complete degradation of MO was achieved when the composites containing 2 × 10−3 wt% of Ag (NR–Ag4) were employed at pH 3. Under this condition, complete degradation occurred within 30 min. Kinetic studies were conducted to understand the degradation phenomenon.

A photodiode based on PbS nanocrystallites for FYTRONIX solar panel automatic tracking controller

The structural, optical and photoelectrical properties of the fabricated Al/PbS/p-Si/Al photodiode based on PbS nanocrystallites were investigated. The PbS nanocrystallites were characterized by X-ray diffraction (XRD), UV–VIS–NIR, Infrared and Raman spectroscopy. The XRD diffraction peaks show that the prepared PbS nanostructure is in high crystalline state. Various electrical parameters of the prepared photodiode were analyzed from the electrical characteristics based on I-V and C-V-G. The photodiode has a high rectification ratio of 5.85×104 at dark and ±4V. Moreover, The photocurrent results indicate a strong photovoltaic behavior. The frequency dependence of capacitance and conductance characteristics was attributed to depletion region behavior of the photodiode. The diode was used to control solar panel power automatic tracking controller in dual axis. The fabricated photodiode works as a photosensor to control Solar tracking systems.

Characterization of Bi2Se3 films prepared by electrodeposition and heat treatment

ABSTRACTBi2Se3 as a semiconductor with narrow band gap about 0.24 eV has good thermoelectric properties. Bi2Se3 thermoelectric films were prepared by electrodeposition using Bi2O3 and SeO2 as raw materials, and the appropriate heat treatment process was adopted to improve the crystallinity of product films. The phases of product films were analyzed by X-ray diffraction (XRD) and the morphology was characterized by scanning electron microscopy (SEM), and the compositions of product films were analyzed by energy dispersive spectroscopy (EDS). The results show that the crystallinity of Bi2Se3 films can be improved significantly when heat treated at 350°C for 2 h or 400°C for 1 h. The XRD diffraction peaks are corresponding to (015), (1 0 10) and (110) crystal planes respectively. The surface of the product films shows particle aggregation, dendritic crystal and a few holes distributing irregularly.

Electrical analysis of inter-growth structured Bi4Ti3O12–Na0.5Bi4.5Ti4O15 ceramics**Project supported by the National Natural Science Foundation of China (Grant Nos. 51562014, 51262009, and 51602135).

Inter-growth bismuth layer-structured ferroelectrics (BLSFs), Bi4Ti3O12–Na0.5Bi4.5Ti4O15 (BIT–NBT), were successfully synthesized using the traditional solid-state reaction method. X-ray diffraction (XRD) Rietveld refinements were conducted using GSAS software. Good agreement and low residual are obtained. The XRD diffraction peaks can be well indexed into I2cm space group. The inter-growth structure was further observed in the high-resolution TEM image. Dielectric and impedance properties were measured and systematically analyzed. At the temperature range 763–923 K (below , doubly ionized oxygen vacancies (OVs) are localized and the short-range hopping leads to the relaxation processes with an activation energy of 0.79–1.01 eV. Above , the doubly charged OVs are delocalized and become free ones, which contribute to the long-range dc conduction. The reduction in relaxation species gives rise to a higher relaxation activation energy ∼1.6 eV.

The Performance and Mechanism Analysis of Cement Pastes Added to Aluminum Sulfate-Based Low-Alkali Setting Accelerator

We proposed a type of low-alkali liquid state setting accelerator, named HLSA; it was environmentally friendly product. To investigate the temperature adaptation and cement flexibilities of HLSA, the setting time and strength development properties of cement with HLSA were discussed in this paper. The effects of HLSA on hydration process, hydration products, and microstructure were studied by means of X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscope (SEM), and mercury intrusion porosimetry (MIP). The results show that four typical 42.5-grade ordinary Portland cement types with 6–8% HLSA could satisfy the first-grade requirements according to JC477-2005 even at a lower temperature (e.g., 10°C). Further, the percentage ratio of 28 d compressive strength of cement with 6–8% HLSA was over 90%; the XRD diffraction peak of AFt integrated area of cement with 7% HLSA was 3818 at 5 min of hydration; SEM observation revealed that AFt crystals were filled in the pore of cement at 28 d of hydration; the temperature adaptation and cement flexibilities of HLSA were excellent; the cement with HLSA coagulating in a short time attributed to promoting the formation of abundant AFt and the hydration of C3S.

Controllable Fe introduction into ordered mesoporous carbon with interconnected small pores for investigating Fe doping effect on hydrogen adsorption

Iron has been proved effective for hydrogen adsorption due to its high binding energy with hydrogen molecules. Here a series of iron-doped interconnected ordered mesoporous carbons (Fe/OMCs) with controllable doping level (zero to 9.11%) and large surface area were successfully prepared by adjusting the initial additive mass of ferric nitrate. The mesoporous carbon materials were characterized by means of nitrogen adsorption, pore size distribution, low-angle X-ray diffractometer, energy dispersive X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectra (FTIR), and X-ray photoelectron spectroscopy (XPS) analyses. The results show that the Fe/OMCs possess well-ordered mesostructured, intrinsic 3D network structure, and large surface area from 921 to 1378 m2 g−1. The low-angle XRD diffraction peaks of the Fe/OMC samples shifted slightly toward high angles, indicating the introduced Fe on the OMC prevents framework shrinkage during the calcination. The controllable iron particles with size of 20–40 nm partially embedded on the 3D network structure showed different state of iron particles, namely zero iron (α-Fe), magnetite (Fe3O4) and hematite (α-Fe2O3), and part of them kept naked in the pore, providing more available iron actives for hydrogen adsorption. Based on the unique structure, adsorption data of hydrogen on the OMC were collected to independently investigate the iron doping effect on the Fe/carbon composite surface interactions. The results indicate that hydrogen adsorption capacity is greatly enhanced with the iron content, and the sample Fe/OMC-9 with 9.11% iron content exhibits the highest hydrogen adsorption capacity of 1.10 wt%, 59% higher than the non-doped OMC. The high hydrogen adsorption is attributed to OMC's 3D porous network structure with well-dispersed iron nanoparticles partially exposed in the pore.

Analysis of the stabilization process of indomethacin crystals via π–π and CH–π interactions measured by Raman spectroscopy and X-ray diffraction

In this study, formations of π–π and CH–π interactions in the crystallization of amorphous indomethacin (IMC) were investigated by simultaneous Raman spectroscopy and X-ray diffraction (XRD) measurements. The activation energy obtained from the change in the peak at 1616cm−1 corresponded to the energy obtained from the XRD diffraction peak at 21.6°. We suggest that the stable IMC crystal forms by carboxyl-carboxyl interactions, which is followed by CH–π and π–π interactions supporting stabilization in the indole and chlorophenyl rings.

A study on Cu and Ag doped ZnO nanoparticles for the photocatalytic degradation of brilliant green dye: synthesis and characterization.

Novel polyvinyl pyrrolidone capped pure, Ag (1-3%) and Cu doped (1-3%) zinc oxide (ZnO) nanoparticles (NPs) were successfully synthesized via the co-precipitation method. The synthesized NPs were characterized by UV-visible spectrophotometry, X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and field emission scanning electron microscopy (FE-SEM). Compared to pure ZnO, the absorption bands of Ag and Cu doped ZnO NPs were shifted and, further, the band gap energy was also decreased which confirms the incorporation of Ag and Cu into the ZnO lattice. The XRD diffraction peak confirms that all the synthesized compounds are found to be of highly crystalline hexagonal wurtzite structure. In addition, the presence of Ag and Cu in the ZnO NPs was further evidenced from EDS analysis. FE-SEM images established the morphology of the doped ZnO NPs which was not affected by the addition of Ag and Cu. The photocatalytic activity of undoped, Ag doped (1-3%) and Cu doped (1-3%) ZnO NPs were tested with brilliant green dye under UV irradiation. Degradation study reveals that doping has a distinct effect on the photocatalytic behavior of ZnO NPs. In addition to that, kinetic, thermodynamic and reusability studies have been performed for the 2% Ag doped ZnO NPs.