Effect Of Synthesis Route Research Articles

Dry reforming of methane over Ni–Mg–Al and Ni–Ca–Al type hydrotalcite-like catalysts: effects of synthesis route and Ru incorporation

Abstract Ni-incorporated Mg–Al type hydrotalcite-like catalytic materials were synthesized following impregnation and co-precipitation routes, and their catalytic performances were compared in the dry-reforming reaction of methane. The effects of Ru impregnation on the catalytic performance of Ni-incorporated Mg–Al were also investigated. Results showed that the catalytic performance of the Ni-incorporated Mg–Al type catalyst (NiMgAlO), which was prepared by the co-precipitation route, was highly stable during dry-reforming reaction tests performed at 600 °C, extending up to 24 h. The fractional conversion of CO2 (0.42) was higher than the fractional conversion of CH4 (0.29) due to the contribution of the reverse water gas shift reaction. However, the contribution of the reverse water gas shift reaction to the product distribution was much less with the catalyst prepared following the impregnation route (Ni@MgAlO). This difference was shown to be mainly due to the state of the nickel in the catalyst structures. Ni-impregnated Ca–Al type hydrotalcite-like catalyst (Ni@CaAlO) was also synthesized and tested in dry reforming of methane. Results obtained with the Ni-impregnated Ca–Al type catalyst showed some changes in its structure and the formation of some CaCO3 during the dry reforming reaction. The comparison of the performances of Ni-impregnated Mg–Al and Ca–Al type catalysts showed a higher amount of coke on the surface of Ni@CaAlO than Ni@MgAlO. It was also concluded that significant coke minimization and highly stable catalytic performance could be achieved by the impregnation of 1 % Ru to the NiMgAlO catalyst. The amount of coke deposited on the catalyst decreased from about 30 % to less than 5 %, by Ru impregnation. The decrease of the surface area of the Ru-impregnated catalyst was also only about 3 % after 240 min of reaction time.

The effects of synthesis route and LaB6-doping on FeCoNiCrTi coating performance: Morphology, microstructure, microhardness and corrosion resistance

In this work, the FeCoNiCrTi HEA coatings were fabricated on the Ti6Al4V surface via laser cladding technology. The effects of synthesis routes (different energy density, Led) and LaB6-doping on the single-track morphology, phase distribution, microstructure, microhardness and corrosion resistance of HEA coatings were comprehensively studied. Interestingly, the regulation of Led and addition of LaB6 significantly reduced the crack sensitivity and dilution rate of the coating. On the one hand, the optimized coating contributed to fine grain size when Led was 73.33 J/mm2. On the other hand, the in-situ generation of TiC, TiB2 and TiC/TiB2 composite structure played an important role in achieving the more excellent propertiy in LaB6/FeCoNiCrTi composite coating. Furthermore, the microhardness and corrosion resistance of the coatings were significantly improved owing to the ceramic phases and fine grain strengthening. Specifically, the average microhardness coating was up to 593 HV0.2. The corrosion current density (Icorr) of the coating with a Led of 73.33 J/mm2 was 4.796 × 10−6 A·cm−2, the carrier density (ND) and thickness (d) of the passivation film were 1.556 × 1022 cm−2 and 3.244 nm, respectively, indicating the best corrosion resistance in HEA coatings. In terms of LaB6/FeCoNiCrTi coating, the Icorr, ND and d were 2.400 × 10−6 A·cm−2, 1.053 × 1022 cm−2 and 4.739 nm, respectively. Consequently, the doping of LaB6 further enhanced the corrosion resistance of HEA coating.

Optical and structural properties of spherical-shaped boehmite and γ-alumina nanoparticles by ultrasonic-assisted hydrothermal method: the effects of synthesis route, calcination, and precursor concentration

Optical and structural properties of spherical-shaped boehmite and γ-alumina nanoparticles by ultrasonic-assisted hydrothermal method: the effects of synthesis route, calcination, and precursor concentration

Effect of synthesis route on electrochemical performance of PrBaCo2O5+δ cathode for IT-SOFC application

Effect of synthesis route on electrochemical performance of PrBaCo2O5+δ cathode for IT-SOFC application

Effect of synthesis route on the photoluminescence properties of SrTiO3:Pr,Al phosphor: Nanoparticles and microcubes

Sr0.998Pr0.002Ti0.998Al0.002O3 phosphors were prepared by hydrothermal (HT) and polymeric precursor (PP) methods. PP sample exhibits broadening of X-ray diffraction peaks due to the higher surface region of nanoparticles compared to HT sample. X-ray absorption spectroscopy results depicted defects associated with the formation of TiO5 octahedra for HT sample, which is ascribed to the rapid crystallization process in HT synthesis of the mesocrystals with cube-like shape. A quenching of 4f → 4f emissions in Pr3+ ions and a broad spectrum are observed for HT sample, which are attributed to structural disorder in the forming and modifying lattice due to charge compensation between Sr-O11 and Sr-O12 (or TiO5 and TiO6) clusters and intermediate levels in band gap states.

Effect of synthesis routes on the microstructural properties of nano zero-valent metals of Fe and Cu synthesized from the industrial copper solvent extraction process

Nano zero-valent iron (NZVI) and nano zero-valent copper (NZVC) synthesizing from the present industrial solution could be attractive due to some advantages such as preparing advanced materials through cost-effective methods and solving their disposal problems. Moreover, the present microstructural investigation probed the influence of synthesis routes used on NZVI and NZVC properties. Accordingly, the microstructural properties of nano zero-valent metals (NZVMs) synthesized through the green and chemical methods were calculated by the Rietveld method. The obtained results verified that NZVI was synthesized with titrating NaBH4 and green tea extract by chemical and green techniques from the industrial raffinate solution. NZVC was prepared from the industrial Cu-enriched solution through green and chemical techniques by titrating ascorbic acid and NaBH4, respectively. XRD and Energy Dispersive Spectroscopy (EDS) proved that NZVMs were synthesized and fairly oxidized. Microstructural studies also revealed that the amorphization degree was increased from 62.2% and 2.7% in the green NZVI and NZVC to 89.8% and 86.81% in chemically synthesized NZVI and NZVC, respectively. Considering green NZVMs, the crystallite size and unit cell were reduced in chemically synthesized NZVMs. Also, the microstrain changed from 2.79E-4% and 3.2E-3% in the green NZVI and NZVC to 2.4E-2% and 6.2E-4% in chemically synthesized NZVI and NZVC, respectively. The findings of this study indicated that the chemically synthesized NZVMs had smaller particles, crystallite size, unit cells and a higher amorphization degree, in favor of reactivity promotion and oxidation progress.

Green and Chemically Prepared Zinc Sulfide Nanoparticles: A Comparative Study

Biosynthesis of zinc sulfide (ZnS) nanoparticles (NPs) using plant extracts is an alternative method to traditional chemical route. In this study, ZnS-NPs was synthesized via two different routes: (i) bio-based method using leaf extract of Plectranthus barbatus as a capping agent and (ii) using the chemical co-precipitation route as a capping–free method. The effect of synthesis routes on the structural, morphological, and optical properties of the prepared NPs was analyzed. The obtained ZnS-NPs was characterized using UV-Visible, FTIR, XRD, and SEM. According to XRD analysis, the average crystallite size were found to be 2.259 and 3.080 nm for chemically and bio-synthesized ZnS, respectively; while SEM revealed aggregated NPs to be counted. Additionally, the optical energy bandgap were 3.82 and 3.73 eV of the samples synthesized via chemical and green methods, respectively. The obtained results indicates that ZnS-NPs prepared via the capping–free chemical route is is more favored, in term of its morphological and optical properties, compared to the sample prepared by green method.

The effect of synthesis route on the photocatalytic performance of Ag-TiO2 using rhodamine b dyes, pesticides, and pharmaceutical waste as model pollutants

The use of noble metal loading such as Ag to improve the photocatalytic performance of TiO2 has been well studied. Though different synthesis methods have been used to synthesize Ag-TiO2 nano-composite, the effect of the different synthesis routes on the photocatalytic performance has not been studied and compared. This study focusses not only on the enhancement of photocatalytic performance by the addition of Ag, but also on the influence of the synthesis process on photocatalytic performance. Two different routes: photodeposition (PD) and formaldehyde assisted microwave (MW) synthesis of Ag-TiO2 nano-composite and their photocatalytic performance were evaluated using model pollutants. The Ag-TiO2 were synthesized using different wt% (0.5, 1.0, 1.5 and 2.0 wt%) of Ag. The synthesized Ag-TiO2 were characterized with x-ray diffractometer, scanning electron microscopy-energy dispersive x-ray spectroscopy (SEM-EDX) and UV–vis spectrophotometry. The Ag-TiO2 photocatalyst showed superior photocatalytic performance towards rhodamine b dye as compared to raw TiO2. 0.5 wt% Ag-TiO2-PD recorded the highest rate constant and degradation percent among the composites synthesized using photodeposition (PD) method. On the other hand, 1.0 wt% Ag-TiO2-MW performed better among the composites synthesized using microwave and formaldehyde assisted synthesis. The potential of these best performing composites; 0.5 wt% Ag-TiO2 and 1.0 wt% Ag-TiO2 to photocatalytically degrade pharmaceutical (Naproxen Sodium and Flurbiprofen) and pesticide (Atrazine and Pyrimethanil) pollutants were examined. These composites degraded the pollutants exceptionally well with 0.5 wt% Ag-TiO2-PD outperforming the 1.0 wt% Ag-TiO2-MW. 1H NMR and 13C NMR analysis revealed that the synthesized Ag-TiO2 were effective in degrading the model pollutants.

Effect of synthesis route on optical properties of Cr:Al2O3 transparent ceramics sintered under high pressure

Transparent polycrystalline ceramics doped with active ions are suitable for many potential optical applications. Fabrication methods that utilize applied external pressure show promise as they allow reducing sintering temperatures and produce transparent non-cubic ceramics. However, not much attention has been given to the dissolution of doping elements while sintering under relatively high pressure and low temperature conditions. In this study, we employed high-pressure spark plasma sintering (HPSPS) for fabrication of Cr:Al 2 O 3 ceramics and investigated the effect of two different synthesis routes on densification and optical properties. Namely, HPSPS of Cr-doped alumina powders prepared by directly doping with 0.05, 0.2, and 0.5 Cr at.% via co-precipitation and alumina mixed with similar mol.% of Cr 2 O 3 nanoparticles towards doping via solid-state reactive sintering (so-called ‘synthesized’ and ‘mixed’, respectively). Remarkable differences in optical properties between samples obtained by each method were observed. The ceramics fabricated from synthesized powders exhibited pink shades of ruby, high transparency, and strong photoluminescence. In contrast, the mixed ceramics exhibited green color, low transparency, and weak photoluminescence. It was found that in the green samples, most of the Cr 2 O 3 nanoparticles remain as undissolved nano-inclusions. These inclusions are detrimental to optical properties and cause green pigmentation of the alumina. Post-sintering heat treatment dissolved the inclusions and the added Cr 3+ in alumina increased photoluminescence. Evidently, doping transparent alumina via reactive sintering is not viable for processes such as HPSPS. Nevertheless, rapid low temperature densification might enable the design of functional translucent ceramics with integrated second phase nanoparticles. • High-pressure spark plasma sintering was used to fabricate polycrystalline Cr:Al 2 O 3 . • Cr-doping via co-precipitation yielded highly transparent Cr 3+ :Al 2 O 3 ceramics. • Mixed Cr 2 O 3 -Al 2 O 3 yielded green translucent ceramics due to Cr 2 O 3 nano-inclusions. • Post-sintering heat treatment dissolved Cr 2 O 3 and increased photoluminescence. • Reactive sintering is not a viable synthesis route for doped transparent alumina.

Halide‐type Li‐ion conductors: Future options for high‐voltage all‐solid‐state batteries

AbstractThe design of high‐energy‐density batteries is the future goal of research on Li‐ion batteries. Halide‐type solid‐state electrolytes (SSEs) exceed their counterparts in terms of their stability at high potential. In this minireview, we discuss the developments in the work on halide‐type SSEs for all‐solid‐state Li batteries. In particular, we focus on the Li3InCl6 structure. The effect of synthesis routes on this structure, as well as the convertible products resulting from its phase changes, is discussed. Conductivity can be increased and the electrochemical window can be improved through doping with different materials. Our review aims to provide readers with an overview of the stability and degradation of Li3InCl6 SSE and the structure of halide‐type SSEs (Li–M–X, where M is a metal and X is a halogen).

Comparative study on the effect of synthesis route on the structural, magnetic, and magnetocaloric properties of La0 .5Ca0.5Mn0.95V0.05O3 manganite

ABSTRACT The influence of the synthesis method on structural, magnetic and magnetocaloric properties of the La0.5Ca0.5Mn0.95V0.05O3 compound has been investigated. The compound was prepared by glycine nitrate process (GNP) and compared to counterparts obtained with solid-state route (S-S) and ball milling (B-M). The structural analysis shows a pure and single-orthorhombic crystalline phase for the GNP compound. A secondary phase LaVO4 was detected for S-S and B-M samples. From magnetization versus temperature analysis, different magnetic behaviors were distinguished when moving from one technique to another. The nature of transition was determined and a crossover from second order to first-order magnetic transition was observed with the decrease of crystallite size. Landau theory was performed to confirm the order of magnetic transition of the sample consistent with the Banerjee criterion. The magnetic entropy change (ΔSm) and the relative cooling power RCP, which decreased by reducing the particle size, were calculated.

Effect of synthesis route on electrocatalytic water-splitting activity of MoS2/UiO-66 hybrid

Development of a low-cost, highly active, and stable catalyst is the most challenging task for an efficient water-splitting process. In this regard, Hybrids composed of transition metals and MOF materials are an attractive possibility to be explored. Such hybrid materials show modified structures along with improved electrocatalytic performance due to the synergistic effects of the two materials. In this paper, we report UiO-66/MoS2 hybrid catalyst synthesized via two different synthesis routes. Their comparative characteristics and activity for overall water-splitting are also discussed. It was observed that Hybrid-2 showed better electrocatalytic performance with Hydrogen Evolution Reaction (HER) overpotential of 129 mV (at ƞ10) and Tafel slope of 51 mV/dec. For Oxygen Evolution Reaction (OER), it showed an overpotential of 180 mV (at ƞ10) and Tafel slope of 64 mV/dec. Moreover, the catalyst was stable for longer periods with very slight loss of activity. The improved results can be attributed to the interaction of the key characteristics of two materials which led to unique architecture of the hybrid and improved electrical connectivity with an increased exposed active surface area that assists in the transportation of charge carriers to the electrode and electrolyte interface. The results suggest that UiO-66/MoS2 hybrids are promising as active and non-expensive electrocatalytic catalyst for overall water-splitting catalyst. The findings also speculate an insight on the effect of the synthesis route on the structure and activity of MOF hybrids with robust catalytic performance.

Effect of Synthesis Route on Microstructure and Magnetic Properties of Alnico Based High Entropy Alloys

Effect of Synthesis Route on Microstructure and Magnetic Properties of Alnico Based High Entropy Alloys

Effect of Synthesis Routes on Microstructural Properties of Nano Zero-Valent Metals of Fe and Cu Synthesized from the Industrial Copper Solvent Extraction Process

Effect of Synthesis Routes on Microstructural Properties of Nano Zero-Valent Metals of Fe and Cu Synthesized from the Industrial Copper Solvent Extraction Process

Effect of Synthesis Route on the Magnetic Properties of Sm1-Xbixfeo3: A Comparative Study between Solid State and Combustion Methods

Effect of Synthesis Route on the Magnetic Properties of Sm1-Xbixfeo3: A Comparative Study between Solid State and Combustion Methods

Effects of synthesis route on the performance of mesoporous ceria-alumina and ceria-zirconia-alumina supported nickel catalysts in steam and autothermal reforming of diesel

Decline in catalyst performance due to coke deposition is the main problem in diesel steam (SR) and autothermal reforming (ATR) reactions. Good redox potential and strong interaction of CeO2 with nickel increase activity and coke resistivity of Ni/Al2O3 catalysts. In this study, mesoporous Al2O3, CeO2/Al2O3, and CeO2/ZrO2/Al2O3 supported nickel catalysts were successfully synthesized. The highest hydrogen yield, 97.7%, and almost no coke deposition were observed with CeO2/ZrO2/Al2O3 catalyst (Ni@8CeO2-2ZrO2-Al2O3-EISA) in SR reaction. The second highest hydrogen yield, 91.4%, was obtained with CeO2/Al2O3 catalyst (Ni@10CeO2-Al2O3-EISA) with 0.3 wt% coke deposition. Presence of ZrO2 prevented the transformation of cubic CeO2 into CeAlO3, which enhanced water gas shift reaction (WGSR) activity. Ni@10CeO2-Al2O3-EISA did not show any decline in activity in a long-term performance test. Higher CeO2 incorporation (20 wt%) caused lower steam reforming activity. Change of synthesis route from one-pot to impregnation for the CeO2 incorporation decreased the number of acid sites, limiting cracking reactions and causing a significant drop in hydrogen production.

Green synthesis of MIL-100(Fe) derivatives and revealing their structure-activity relationship for 2,4-dichlorophenol photodegradation

MIL-100(Fe), a kind of iron-based metal-organic framework materials (MOFs), can be synthesized at room temperature or hydrothermal conditions, which are promising precursor materials for preparing photocatalysts to degrade some recalcitrant chlorophenols in industrial wastewater. However, the relationship between the structural characterization of MIL-100(Fe) derivatives and their photodegradation behavior of chlorophenol pollutants is still unclear. Thus, in this work, a porous Z-scheme α-Fe2O3/MIL-100(Fe) composite was successfully fabricated via partial-pyrolysis of MIL-100(Fe) precursor synthesized through green synthesis route, which was further used for degrading high-concentration of 2,4-dichlorophenol under visible-light illumination (λ > 420 nm). The effects of synthesis route and pyrolysis temperature of MIL-100(Fe) on the degradation efficiencies of as-derived materials for 2,4-dichlorophenol were investigated. The structure-activity relationship was illuminated in detail. Otherwise, the influence of several process factors, i.e., initial concentration and pH of the 2,4-dichlorophenol solution, catalyst dosage on the degradation efficiency of 2,4-dichlorophenol has also been performed. The removal efficiency of 2,4-dichlorophenol with the initial concentration of 100 mg L−1 reached up to 87.65% under optimized conditions. Lastly, the possible mechanism was explored based on trapping experiments and some other characterization results. The study in this paper not only exhibited new insight into the modified α-Fe2O3 material with high photocatalytic activity but also provided a promising method for treating wastewater containing 2,4-dichlorophenol or other similar organic pollutants.

Effect of synthesis route on the structural and electrical properties of sodium bismuth titanate: A comparative study of solid-state and polyol mediated synthesis

Sodium bismuth titanate (NBT) was synthesized through two different synthesis methods: solid-state reaction (SS) and polyol mediated synthesis (PM). The effect of synthesis route on the structural and electrical properties of NBT system has been investigated. Polyol mediated synthesize NBT sample result in single-phase at relatively lower temperature than of prepared via the solid-state reaction method. The Rietveld refinement of the XRD data confirms that both the sample crystallizes in the rhombohedral perovskite phase with R3c space group. The morphological properties indicate that the grain size of the polyol method processed sample is smaller and slightly agglomerated than the one prepared via solid-state route. Impedance results reveal enhanced bulk conductivity for PM synthesized samples as compared to SS route. Thus, the polyol mediated synthesis may be a better approach for the synthesis of NBT samples. Furthermore, a correlation between the structural and electrical properties for both methods synthesized samples have been discussed to explain the conductivity behaviour.

Effect of Synthesis Route on Photocatalytic Properties of 10% Ti Doped Bifeo3 Nanoparticles

Effect of Synthesis Route on Photocatalytic Properties of 10% Ti Doped Bifeo3 Nanoparticles

Effect of synthesis route on structural, morphological, Raman, dielectric, and electric properties of La0.8Ba0.1Bi0.1FeO3

Two compounds with the formula La0.8Ba0.1Bi0.1FeO3 have been prepared by the sol–gel (LBBFO-SG) and the auto-combustion (LBBFO-AC) preparation methods. The effect of the preparation method on structural, morphology, vibrational, electrical, and dielectric properties have been carried out using the X-ray diffraction (XRD), Scanning electron microscopy (SEM), and Raman and impedance spectroscopy. The Rietveld refinement of the XRD diffractograms confirms the crystallization of both compounds through the Pnma space group. Furthermore, the nano-size scale of the prepared compounds was verified by the XRD and the SEM microscopy. From the Raman study, we conclude that the vibration modes are similar to those of the pure LaFeO3 with a slight shape change in some modes. The relaxation processes were analyzed with the Bergmann formalism to validate the presence of two relaxation processes corresponding to grains and boundary grains contributions. These relaxations have been confirmed by studying the dielectric constant also the dielectric loss tangent is used to study the ferroelectric–paraelectric phase transition at around room temperature. The activation energy for both contributions has been calculated from the impedance, the modulus, and the dielectric loss tangent and they have almost the same values. The Nyquist plots (Z″ vs. Z′) have been adjusted using two circuits in series containing each one a resistance in parallel to a CEP capacitance.