Addition Of CeO2 Research Articles

Insight into the effect of catalytic reactions on correlations of soot oxidation activity and microspatial structures

A catalyst is usually coated on Diesel particulate filter (DPF) for assisted regeneration. In this paper, the oxidation activity and pore structure evolutions of soot under the effect of CeO2 are explored. CeO2 effectively increases the oxidation activity of soot and reduces the initial activation energy; in the meantime, the addition of CeO2 changes the soot oxidation mode. Pure soot particles tend to produce the porous structure in the oxidation process. Mesopores promote the diffusion of oxygen, and macropores contribute to reduce the agglomeration of soot particles. Additionally, CeO2 provides the active oxygen for soot oxidation and promotes the multi-point oxidation at the beginning of soot oxidation. With the oxidation proceeding, catalysis causes the collapsion of soot microspatial structures, in the meantime, the macropores caused by the catalytic oxidation are filled by CeO2. It results in the tight contact between soot and catalyst, further promoting the formation of the available active oxygen for soot oxidation. This paper is meaningful to analyze the oxidation mechanism of soot under catalysis, which lays a foundation for improving the regeneration efficiency of DPF and reducing the particle emission.

Pt2CeO2 Heterojunction Supported on Multiwalled Carbon Nanotubes for Robust Electrocatalytic Oxidation of Methanol

Herein, we prepared Pt2CeO2 heterojunction nanocluster (HJNS) on multiwalled carbon nanotubes (MWCNTs) in deep eutectic solvents (DESs) which is a special class of ionic liquids. The catalyst was then heat-treated at 400 °C in N2 (refer to Pt2CeO2/CNTs-400). The Pt2CeO2/CNTs-400 catalyst showed remarkably improved electrocatalytic performance towards methanol oxidation reaction (MOR) (839.1 mA mgPt-1) compared to Pt2CeO2/CNTs-500 (620.3 mA mgPt-1), Pt2CeO2/CNTs-300 (459.2 mA mgPt-1), Pt2CeO2/CNTs (641.6 mAmg-1) (the catalyst which has not been heat-treated) and commercial Pt/C (229.9 mAmg-1). Additionally, the Pt2CeO2/CNTs-400 catalyst also showed better CO poisoning resistance (onset potential: 0.47 V) compared to Pt2CeO2/CNTs (0.56 V) and commercial Pt/C (0.58 V). The improved performance of Pt2CeO2/CNTs-400 catalyst is attributed to the addition of appropriate CeO2, which changed the electronic state around the Pt atoms, lowered the d-band of Pt atoms, formed more Ce-O-Pt bonds acting as new active sites, affected the adsorption of toxic intermediates and weakened the dissolution of Pt; on the other hand, with the assistance of thermal treatment at 400 °C, the obtained Pt2CeO2 HJNS expose more new active sites at the interface between Pt and CeO2 to enhance the electrochemical active surface area (ECSA) and the dehydrogenation process of MOR. Thirdly, DES is beneficial to the increase of the effective component Pt(0) in the carbonization process. The study shows a new way to construct high-performance Pt-CeO2 catalyst for the direct methanol fuel cell (DMFC).

Optical Properties of Cerium Oxide Doped Zinc Borotellurite Glass

The addition of rare earth, zinc, and borate in tellurite glass was found can enhance the glass properties and overcome its existing weaknesses. These include improving the glass forming ability and stability. In this study, cerium-doped zinc borotellurite glasses were produced using conventional melt-quenching technique and the optical properties of the glasses were investigated. UV-VIS spectra show that the absorption edge shifted to a higher wavelength with CeO2 addition from 0 until 0.05 mol. Consequently, the direct and indirect optical band gap was found to decrease from 3.60 to 2.07 eV and 3.28 to 1.46 eV respectively. On the contrary, the refractive index was found to increase from 2.326 to 3.017. This is attributed to the presence of cerium ions and the formation of non-bridging oxygens. Besides that, the Urbach energy found to be maximum at 0.02 mol CeO2 and minimum at 0.00 mol CeO2. This indicates that there are some structural disorders occur in the glass network as CeO2 introduced into the system. The molar refraction, molar polarizability, oxide ion polarizability and optical basicity exhibited similar trend of data as the CeO2 content was increased which signifies the relation of these parameters. Meanwhile, the metallization criterion is reported to be decreased, indicating that the glass sample become more metallized with the addition of cerium oxide.

Boosting diethylamine selective oxidation over CuO/ZSM-5 catalyst by CeO2 modification

Selective catalytic oxidation of nitrogen containing volatile organic compounds (NVOCs) is very meaningful but still remains big challenge because it is very difficult to balance the oxidation activity and N2 selectivity of available catalysts. In order to develop excellent catalysts with high N2 selectivity in wide temperature window (△T) during NVOCs oxidation, CeO2 modified CuO/ZSM-5 catalysts with different CeO2 addition order were prepared for diethylamine (DEA) oxidation. Detailed characterizations of catalysts such as XRD, XPS, H2-TPR and NH3-TPD were conducted, it is found that addition of CeO2 obviously changes the geometrical and electronic states of CuO active sites in the catalyst, and CeO2 addition order affects the Ce3+ ratio on the catalyst surface. Promotion of CeO2 species enables the generation of more highly active Cu species (Cu+ species and finely dispersed CuO clusters) for DEA oxidation; and synergistic catalysis of the Ce3+ species, active Cu species and acid sites in ZSM-5 leads to the high N2 selectivity in wide temperature window (△T). Compared to the CeO2/CuO/ZSM-5 and CuO-CeO2/ZSM-5 catalysts, the CuO/CeO2/ZSM-5 catalyst exhibits moderate high oxidation activity with T99 of 230 °C and the widest △T of 150 °C for high N2 selectivity. Our primary results in this work provide the efficient strategy for improving catalyst employed for NVOCs selective oxidation.

CO2 hydrogenation to methanol over Zr- and Ce-doped indium oxide

In recent decades, climate change has become a major issue that needs to be addressed. Many efforts have been made on the reduction of CO2 emissions and its conversion in energy carriers and high value-added products such as methane, methanol, dimethyl-ether, and hydrocarbons. The present study focuses on the development of catalysts for hydrogenating CO2 to methanol, which is a useful chemical and an alternative liquid fuel. According to the literature, In2O3-based catalysts are particularly selective in the hydrogenation of CO2 to methanol, reducing the production of CO even at high space velocities compared to the more common ternary catalysts such as Cu/ZnO/Al2O3 or Cu/ZnO/ZrO2. Therefore, the effects of CeO2 and ZrO2 on In2O3-based catalysts were investigated in the present study. The InxCe100−x and the InxZr100−x mixed oxides catalysts were synthesized via gel-oxalate coprecipitation by varying the atomic ratios between the elements. Subsequently, they were analysed with several characterisation techniques to rationalise the catalytic performances that were obtained by testing the samples in a fixed bed reactor under different reaction conditions. The addition of different amounts Ce or Zr modified the structure and morphology of the samples and promoted the adsorption of CO2 from 1.8 mmolCO2⋅gcat−1 up to 10.6 mmolCO2⋅gcat−1. ZrO2 stabilises the structure and the results suggests that the greater specific activity (168 mgCH3OH⋅gIn2O3−1⋅h−1 at 300 °C and 2.5 MPa of In40Zr60) could be ascribed to the electronic promotion of Zr. On the contrary, the addition of CeO2 did not reveal a beneficial effect on the activity. Concerning the stability, In2O3-ZrO2 binary oxides seemed to be affected mainly by sintering; whereas In2O3-CeO2 were affected by at least three deactivating phenomena: sintering, reduction of In2O3 to metallic indium and coking. Consequently, the deactivation rate of these binary oxides increased from 1.04 ⋅ 10−2 h−1 of the In100 to 4.13 ⋅ 10−2 h−1 of the In40Ce60.

Enhancement effect of Ce addition on Mn3O4/diatomite sorbent for moderate-temperature flue gas desulfurization

To improve the performance of single manganese oxide (MnOx) for moderate-temperature flue gas desulfurization, a series of cerium (Ce) modified Mn3O4/diatomite sorbents with different Ce/Mn molar ratios are prepared by the sol–gel method. Results show that the desulfurization performance of single Mn-based sorbents is significantly enhanced by the addition of CeO2. The strong redox couples are formed between CeO2 and Mn3O4 to further improve the desulfurization activity of sorbents. Moreover, the agglomeration of active component on the surface of carrier is restrained by the designed CeO2-Mn3O4 binary oxides with a micro-reticulated framework to provide more active sites, which is conducive to improving the utilization of active component. The M2C2D6 sorbent is verified as the most outstanding sorbent with the desulfurization efficiency of 96 %, sulfur capacity of 221 mg-SO2/g-sorbent and breakthrough time of 251 min. To master the reaction path and control the types of products, the mechanism of desulfurization-regeneration of M2C2D6 is systematically elaborated by the combination of thermodynamic calculation and product calibration. The above results further prove the effectiveness of Ce doping in the enhancement of desulfurization performance of single Mn-based sorbents for moderate-temperature flue gas desulfurization.

Thermal, Structural, Morphological and Electrical Characterization of Cerium-Containing 45S5 for Metal Implant Coatings

Biomaterial coatings on dental implants are increasingly being used as a solution to the problems of rejection and implant loss. Bioglass® has been seen as a promising material for coating metal implants, increasing the integration rate and improving the bond between the bone and the implant. Multifunctional bioactive glasses can exhibit antibacterial, antitumor and antioxidant effects with the addition of therapeutic ions. The cerium ion has shown an antioxidant effect through mimicking mechanisms and by acting as a scavenger of reactive oxygen species (ROS), which is important for avoiding oxidative stress post-surgery. Furthermore, it is possible to store electrical charge on the bioglass surface, which potentiates osseointegration. In this work, glasses with various percentages of cerium oxide (0.25, 0.5, 1 and 2 mol%) were developed and structurally and electrically analyzed. It was verified that the cerium insertion did not modify the amorphous phase characteristic of the glass but showed an increase in the number of non-bridging oxygens (NBOs). This increase in NBOs did not modify the electrical conductivity in either the ac or dc regime. The similar permittivity values of the glasses also suggest that their storage ability is unchanged with the addition of CeO2. Concerning the impedance spectroscopy (IS) data, a decrease in resistance is visible with the addition of cerium oxide, suggesting a favorable behavior for applications as an antioxidant through the electro-Fenton reaction.

Achieving illustrious friction and corrosion resistance on a laser powder bed fusion nitinol rare earth alloy

Recently, laser powder bed fusion of nitinol alloys (LPBF-NiTi) has attracted much attention due to its ability to precisely form complex parts. However, the wear and corrosion resistance is crucial for practical applications of LPBF-NiTi alloys. Rare earth oxides are common additives used to improve the surface properties of alloys. In this work, nano-sized cerium oxide (CeO2) is selected as the additive, and the influence rule and mechanism of different addition amounts of CeO2 on the surface properties of LPBF-NiTi alloy are deeply studied. The results showed that the addition of an appropriate amount of CeO2 (0.03 wt% CeO2 addition) could effectively refine the grains and improve the grain order, which achieved the improvement of the mechanical properties (tensile strength and toughness) of the LPBF-NiTi alloy. Furthermore, the reduction in friction coefficient and wear scar depth/width proved that the addition of CeO2 effectively improves the wear resistance of LPBF-NiTi alloys, which were mainly attributed to the synergistic action of the precipitation of the secondary hard phase (NiCe), the grain refinement strengthening, and stable phase transformation brought about by high latent heat of transformation. In addition, the improvement of anti-corrosion was reflected in the reduction of corrosion current density Icorr and pitting pits, mainly due to the formation of NiCe precipitates and grain refinement, which effectively hindered the propagation and extension of pitting corrosion. Most significantly, the 0.03% CeO2 sample achieved the simultaneous improvement of mechanical properties and surfaced functional properties, which greatly expanded the application prospects of NiTi–CeO2 alloys.

Anti-tribocorrosion resistance of NiTi–CeO2 alloys fabricated by laser powder bed fusion

Alloying treatment is a common method to enhance metallic properties, but its application in laser powder bed fusion (LPBF) is still very limited, especially for LPBF-NiTi alloys. Rare earth elements as common alloying elements have been used in the modification of different LPBF- metals. In the case of LPBF-NiTi alloy, the application of rare earth alloying is only for mechanical functionality, but its influence on anti-tribocorrosion resistance is always neglected. In this paper, SEM, EDS, EBSD and TEM were used to characterize the microstructure and composition of the two samples with and without CeO2 addition, and the anti-tribocorrosion resistance was studied in 3.5 wt% NaCl solution. The results show that the addition of 0.03% CeO2 can weaken the strong texture of LPBF-NiTi alloy in the direction of (001), but also plays a role in refining grain. Meanwhile, the formation of a new NiCe phase and lattice distortion was found in TEM. In addition, the addition of 0.03% CeO2 improves the anti-tribocorrosion resistance of LPBF-NiTi alloy in 3.5%NaCl solution significantly.

Solution combustion synthesis of novel PrFeO3/CeO2 nanocomposite with enhanced photo-Fenton activity under visible light

In this study, we successfully synthesized PrFeO3/CeO2-based nanocomposites with different mass contents of СeO2 (0–18 wt%) via solution combustion with subsequent heat treatment in air. The results of EDXS and PXRD confirmed the presence of two phases in nanocomposites: a PrFeO3 orthorhombic phase with an average crystallite size of 13.6–36.6 nm and a СeO2 cubic phase in the form of an ultradisperse phase with an average particle size of 7.4–11.5 nm depending on the mass content of СeO2. We characterized the morphology, porosity, and specific surface structure of the powders by scanning electron microscopy, transmission electron microscopy, and adsorption–structural analysis, which established the foam-like morphology of nanopowders with a predominantly mesoporous structure. The specific surface area varied in the range of 8.8–19.4 m2/g for different СeO2 contents. We studied the optoelectronic properties of the nanocomposites with UV–visible diffuse reflection spectroscopy, which determined the values of the band gap of the PrFeO3 phase actively absorbing radiation in the visible region (2.07–2.13 eV). Based on the adsorption–photocatalytic properties of the obtained nanocomposites, we established the presence of a synergistic effect from the addition of CeO2 to PrFeO3. We studied the adsorption capacity of the samples during the adsorption of methyl violet, and we analyzed the resulting adsorption isotherm in accordance with the Freundlich model. The obtained results indicated increased dye adsorption in the presence of CeO2, with the maximum value of Kf = 45.7 observed at 15 wt%. We studied the photocatalytic Fenton-like activity of nanopowders during the degradation of methyl violet under the influence of visible light. We established he presence of a positive effect of CeO2 additive. At 9 wt% content, the maximum photocatalytic reaction rate constant was reached at 0.056 min−1, which was previously unavailable for analogical Fenton-like photocatalysts based on REE orthoferrites. Based on the conducted studies, we propose a possible mechanism of the photo-Fenton-like decomposition of organic pollutants in the presence of PrFeO3/CeO2 under the influence of visible light. The obtained nanocomposite materials were also characterized by high cyclic stability and the potential for magnetically controlled separation from the reaction solution, showing their potential as a basis for photocatalysts in wastewater treatment from dyes and other organic pollutants.

High value utilization of waste blast furnace slag: New Ni-CeO2/hBFS catalyst for low temperature CO2 methanation

In the steel industry, large amounts of blast furnace slag (BFS) by-products are inevitably produced and a lot of carbon dioxide is emitted. But at present, slag reuse technology has low added value. In this paper, a high value-added process using blast furnace slag to prepare catalysts for the hydrogenation of carbon dioxide to methane was proposed. Ni-CeO2/hBFS catalyst was prepared by primary wet impregnation using nitric acid modified blast furnace slag (BFS) as a support. CO2 conversion of Ni-CeO2/hBFS catalysts achieved 81.6 % at 350 °C, and the catalyst was not significantly deactivated in a 100 h stability test. The results indicate that: the addition of CeO2 improved the dispersion of Ni particles at high loadings, limited the growth of the Ni particle size and enhanced the synergy between the CO2 adsorption sites, the catalytic active sites and the support, thus improved the catalytic performance at low temperatures. This study provides an effective way for carbon dioxide emission reduction and high-value utilization of blast furnace slag, and developed a Ni-CeO2/hBFS catalyst with superior stability and catalytic performance in long-term operation, thus, the catalyst has great potential for industrial application in the carbon dioxide methanation reaction.

Response surface methodology-based optimization of the amount of cerium dioxide (CeO2) to increase the performance and reduce emissions of a diesel engine fueled by cerium dioxide/diesel blends

The supplement of metal nanoparticles to diesel fuel in specific amounts has been included as an innovative approach to the studies on reducing pollutant emissions of compression ignition engines. In present research, the impacts of adding cerium dioxide (CeO2) nanoparticles, which is a highly oxidizing and reactive additive, to diesel fuel in different amounts (25, 50, 75, and 100 ppm) were experimentally investigated at different engine loads (8, 12, 16, 20, and 25 Nm) and optimized using the response surface methodology (RSM). According to the experimental results, the supplement of CeO2 decreased the brake-specific fuel consumption (BSFC) and enhanced the brake-thermal efficiency (BTHE) and exhaust gas temperature (EGT). On the other hand, the addition of CeO2 caused a decrease in hydrocarbon (HC), carbon monoxide (CO), and smoke emissions, and on the contrary, an increase in nitrogen oxide (NOx) emissions. Under the RSM findings, determined the optimal CeO2 quantity and engine load as 100 ppm and 12 Nm, respectively. Optimum responses corresponding to optimal CeO2 and engine load were determined as 23.125%, 429.766 g/kWh, 335.143 °C, 0.257%, 130.898 ppm, 786.309 ppm, and 25.654% for BTHE, BSFC, EGT, CO, HC, NOx, and smoke, respectively. Optimal results were obtained with a high desirability value of 0.7115. A good agreement between the experimental and RSM-predicted response values indicates that the developed RSM design was successful.

Microstructure and dielectric properties of CaCu3Ti4O12-xCeO2 ceramics

(1-x)CaCu3Ti4O12-xCeO2 (x=0.1, 0.2, 0.3, 0.4) and CaCu3Ti4O12 ceramics were synthesized through a solid-state reaction technique. X-ray diffraction indicates that the CaCu3Ti4O12 phase is formed in all ceramics. SEM micrographs show that the grain size of ceramics declines with the addition of CeO2, which is attributed to the solute drag effect. When the addition amount of CeO2 is 0.4, the ceramic obtains the maximum dielectric constant at low frequency. Increasing the composite content of CeO2 can effectively reduce the dielectric loss of CCTO ceramics at high frequency. And the lowest value is 0.1 when the addition amount of CeO2 is 0.3. Impedance analysis shows that the lowest dielectric loss obtained for the ceramic is due to the lowest grain resistance.

Investigation on microstructure evolution and corrosion resistance of CeO2 particle reforcemented Aluminum matrix composites by powder metallurgy

Aluminum matrix composites reinforced by cerium oxide particles with different contents (0, 5%, 10%, 15% and 20%) were prepared by powder metallurgy. The morphology and structure of the composites were characterized by X-ray diffraction and scanning electron microscope. The corrosion behavior of CeO2 particle reinforced aluminum matrix composites with different content in 3.5% NaCl solution was tested by Tafel polarization curve. The results show that CeO2 is evenly distributed in the matrix, and the addition of CeO2 can effectively reduce the corrosion rate and improve the corrosion performance.

Investigation of ethanol fuel electrooxidation reaction on Ni-CeO2NRs anode electrocatalyst in alkaline media

In this study, Ni-CeO 2NR anode electrocatalysts were synthesized for EOR in alkaline media. Physicochemical and electrochemical characterizations of the catalysts were made • Ni-CeO 2NRs electrocatalysts were synthesized for EOR in alkaline media at various weight ratios. • Physicochemical characterizations of the Ni-CeO 2NRs electrocatalysts were investigated by XRD, SEM, EDS, EDAX, XPS, and TEM analysis. • CV, LSV, and CA tests were conducted to investigate the electrochemical performance of the Ni-CeO 2NRs electrocatalysts. • Ni-CeO 2NRs -2 showed better EOR performance among the synthesized electrocatalysts. One of the most promising, non-toxic, and economical alternative fuels is ethanol and ethanol electrooxidation reaction (EOR) must be completed efficiently to generate energy from ethanol. However, this clean alternative fuel cannot be used commercially because of the slow kinetics of the EOR. In this study, Ni cocatalyzed with CeO 2 nanorods (Ni-CeO 2NRs ) at different weight ratios was synthesized via modified polyol method as a transition metal-based efficient anode electrocatalyst for EOR. Morphological characterizations of the synthesized electrocatalysts were made by XRD, SEM, EDAX, TEM, and XPS analysis and the results were indicated that the catalysts were synthesized successfully. Electrochemical characterizations of the catalysts were investigated by Cyclic Voltammetry (CV), Linear Sweep Voltammetry (LSV), and Chronoamperometry (CA) techniques. CV tests exhibited that Ni-CeO 2-NRs -2 electrocatalyst displayed the highest current density (14.02 mA cm -2 ) among the synthesized catalysts and according to CA experiments, addition of CeO 2 NRs improved the catalytic stability by increasing synergistic effect.

Influence of B-site substituent Ce on thermophysical, oxygen diffusion, and mechanical properties of La2Zr2O7

Pyrochlore-type La2Zr2O7 (LZ) is a promising candidate for high-temperature thermal barrier coatings (TBCs). However, its thermal expansion coefficient and low fracture toughness are not optimal for such application and thus, need to be improved. In this study, we systematically report the effect of CeO2 addition on phase formation, oxygen-ion diffusion, and thermophysical and mechanical properties of full compositions La2(Zr1−xCex)2O7 (x = 0, 0.1, 0.3, 0.5, 0.7, 0.9, 1). La2(Zr1−xCex)2O7 exhibits a pyrochlore structure at x ≤ 0.3, while a fluorite structure is observed outside this range. With the increase in CeO2 content, thermal expansion coefficient and oxygen-ion diffusivity in La2(Zr1−xCex)2O7 are increased. Oxygen-ion diffusivity of La2(Zr1−xCex)2O7 is two orders of magnitude less than that of classical 8YSZ. Among La2(Zr1−xCex)2O7 compounds, La2(Zr0.7Ce0.3)2O7 and La2(Zr0.5Ce0.5)2O7 exhibit relatively low oxygen diffusivities. The composition La2(Zr0.5Ce0.5)2O7 presents the lowest thermal conductivity due to the strongest phonon scattering and also the highest fracture toughness due to the solid-solution toughening. The highest sintering resistance is achieved by the composition La2(Zr0.7Ce0.3)2O7 because of its ordered pyrochlore structure and high atomic mass of Ce. Based on these results, the compositions La2(Zr0.5Ce0.5)2O7 and La2(Zr0.7Ce0.3)2O7 are alternatives for classical 8YSZ for TBC materials operating at ultrahigh temperatures.

Modulating multi-active sites in CeO2-modified MnOx/ZSM-5 catalyst for selective catalytic oxidation of diethylamine

An efficient MnOx/CeO2/ZSM-5 catalyst was developed for selective oxidation of diethylamine (DEA) with high N2 selectivity in a wide temperature window (ΔT = 140 °C), owing to the existence of oxidation and selective catalytic reduction (SCR) active sites. MnOx species prefer to locate on the surface of CeO2 compared to ZSM-5, and the presence of CeO2 is beneficial to form more Mn4+ species, the active sites for oxidation reaction. The mechanistic investigation suggests that internal SCR of NOx generated from the over-oxidized DEA is the crucial pathway for N2 generation. The high SCR activity of the MnOx/CeO2/ZSM-5 catalyst in oxidation conditions is mainly attributed to the synergistic catalysis of Mn4+ species and acid sites of ZSM-5, the active sites for SCR reaction. Thus, it has been clearly clarified that addition of CeO2 and its addition sequence could modulate the surface active sites of MnOx/ZSM-5 catalyst for the selective catalytic oxidation of DEA.

Cost‐effective fabrication of α‐SiAlON ceramics with CeO2 addition for cutting tool applications

AbstractSiAlON ceramic tools exhibit unique performance superiority in the machining of nickel‐based heat‐resistant superalloys (HRSA). Production cost is a critical obstacle for the wide application of SiAlON inserts. In this work, the cost‐effective preparation of α‐SiAlON ceramics was implemented using aqueous slurry, and the effects of CeO2 content on the densification, phase composition, microstructure, mechanical properties, and toughening mechanism of the materials were investigated. The addition of CeO2 enhanced the anisotropic growth of α‐SiAlON grains, which enabled the ceramics to obtain higher flexural strength and fracture toughness. Although a decrease in Vickers hardness would occur when CeO2 content was 3 or 5 wt.%, ascribed to the amount increase of the intergranular phase in the samples. The α‐SiAlON ceramics doped with 1‐wt.% CeO2 achieved the extremely high density and mechanical properties with the relative density, flexural strength, Vickers hardness, and fracture toughness of 99.6% ± .1%, 931 ± 62 MPa, 19.7 ± .2 GPa, and 7.2 ± .2 MPa m1/2, respectively, which could be a candidate cutting tool material for use in the efficient machining of nickel‐based HRSA.

OPTIMIZATION OF THERMOPHYSICAL PROPERTIES, COMBUSTION PERFORMANCE AND HARMFUL EXHAUST GASES OF BIODIESEL FUEL WITH NANOPARTICLE ADDITIVES

Increasing use of diesel products causes decrease of oil reserves, global warming, increase in the world average and adverse effects on human health and the environment. Emissions from combustion in engines are directly related to the quality, properties and combustion characteristics of the fuel. Since the physical and chemical properties of the fuel affect the atomization characteristics, it is important for increasing the combustion efficiency. The most important fuel properties affecting the combustion of diesel fuel are cetane number, viscosity, density and calorific value. There are many applications in improving the chemical and physical properties of fuel. One of them is nanoparticle (NPs) additives adding in fuel. In this study, it was aimed to improve fuel properties with optimum additive ratio by adding CeO2, TiO2 and Co3O4 nanoparticle additives into biodiesel which are produced from cotton and canola oil. The effects of NPs additives in fuel properties such as viscosity, density, lower calorific value and flash points were investigated.

Thermal decomposition kinetics and combustion performance of paraffin-based fuel in the presence of CeO2 catalyst

In recent years, significant developments have been made in solid-fuel combustion. Paraffin-based fuels could be a potential solid fuel for hybrid and ramjet applications due to their high regression rate, low cost, and minimal environmental impact. This study examines the thermal and combustion performance of paraffin-based fuels loaded with CeO2 combustion catalysts and Al additive. A typical melt-cast technique was used to prepare three different fuel formulations, which are paraffin/10 wt.% of Al (S2), paraffin/10 wt.% of CeO2 (S3), and CeO2-Al (10:10 wt.%) binary composite (S4). The pure paraffin (S1) fuel was manufactured as a reference formulation. The CeO2-Al binary composite powder was prepared by ball-milling of CeO2 and Al powders. The CeO2 and Al nanoparticles were characterized by X-ray diffraction (XRD), particle size distribution (PSD), and scanning electron microscope (SEM). The PSD study revealed that the majority of CeO2, Al, and CeO2-Al binary composite particles are 29 nm, 34 nm, and 26 nm in size, respectively. The thermogravimetric analysis (TGA) was used to investigate the effect of CeO2 and Al on the thermal decomposition of paraffin. The results indicate that the paraffin decomposes faster and at a higher rate when CeO2 and CeO2-Al binary composite additives were added. The activation energy of paraffin-based fuel (S4) was reduced from 254 kJ/mol to 214 kJ/mol when a CeO2-Al combustion catalyst was added. The lab-scale ballistic tests showed that the average regression rate of paraffin-Al (S2) and paraffin-CeO2(S3) samples increased in the range of 1.1-1.4 mm/s and 1.12-1.38 mm/s, respectively, whereas, with the CeO2-Al binary composite (S4) sample, a reasonable improvement of 1.15 mm/s to 1.49 mm/s was reported.