Structural Defects Research Articles

Effects of Temperature and Random Forces in Phase Transformation of Multi-Stable Systems

Multi-stable behavior at the microscopic length-scale is fundamental for phase transformation phenomena observed in many materials. These phenomena can be driven not only by external mechanical forces but are also crucially influenced by disorder and thermal fluctuations. Disorder, arising from structural defects or fluctuations in external stimuli, disrupts the homogeneity of the material and can significantly alter the system’s response, often leading to the suppression of cooperativity in the phase transition. Temperature can further introduce novel effects, modifying energy barriers and transition rates. The study of the effects of fluctuations requires the use of a framework that naturally incorporates the interaction of the system with the environment, such as Statistical Mechanics to account for the role of temperature. In the case of complex phenomena induced by disorder, advanced methods such as the replica method (to derive analytical formulas) or refined numerical methods based, for instance, on Monte Carlo techniques, may be needed. In particular, employing models that incorporate the main features of the physical system under investigation and allow for analytical results that can be compared with experimental data is of paramount importance for describing many realistic physical phenomena, which are often studied while neglecting the critical effect of randomness or by utilizing numerical techniques. Additionally, it is fundamental to efficiently derive the macroscopic material behavior from microscale properties, rather than relying solely on phenomenological approaches. In this perspective, we focus on a paradigmatic model that includes both nearest-neighbor interactions with multi-stable (elastic) energy terms and linear long-range interactions, capable of ensuring the presence of an ordered phase. Specifically, to study the effect of environmental noise on the control of the system, we include random fluctuation in external forces. We numerically analyze, on a small-size system, how the interplay of temperature and disorder can significantly alter the system’s phase transition behavior. Moreover, by mapping the model onto a modified version of the Random Field Ising Model, we utilize the replica method approach in the thermodynamic limit to justify the numerical results through analytical insights.

Research Progress on Embryonic Development, Genetic Regulation and Clinical Management of Congenital Middle Ear Malformations

ABSTRACTCongenital middle ear malformations are a common hearing defect in newborns, primarily characterised by abnormal middle ear structures, particularly underdeveloped or malformed ossicular chains, resulting in conductive hearing loss. This article provides a comprehensive review of the embryonic development process of the middle ear and the genetic regulatory mechanisms, with a focus on the Tbx1 gene, which is closely related to middle ear development. Studies have shown that the Tbx1 gene plays a crucial role in the migration of neural crest cells and the formation of middle ear structures, and its mutation or abnormal expression can lead to developmental defects of the middle ear structure. These gene mutations affect downstream signalling pathways (such as FGF8, FGF10 and BMP4), which are essential in the formation of the ossicles, ear canal and middle ear cavity. Additionally, this article discusses the aetiology of congenital middle ear malformations, associated syndromes, clinical manifestations, classification, diagnosis and treatment strategies. Diagnostic methods for middle ear malformations include audiological examinations, imaging studies and genetic testing. Early diagnosis and intervention, such as surgical correction and the use of hearing aids, can help improve the hearing and quality of life of patients. This article aims to provide a reference and basis for further etiological research and precise treatment by elucidating the mechanisms and clinical features of middle ear malformations.

Entropy Manipulation of SrTiO3 Perovskite for Enhanced Thermoelectric and Mechanical Properties.

Reducing the thermal conductivity while maintaining excellent electrical transport properties is crucial for enhancing the thermoelectric performance of SrTiO3-based perovskites. Here, we successfully achieved this goal through precisely manipulating the configurational entropy. A series of Ca0.25Nd0.25Sr0.5-x BaxTiO3 (x = 0, 0.05, 0.15, 0.25) ceramics were successfully synthesized using the solid-state reaction combined with graphite burial sintering. It was discovered that structural defects from competing elements in the A-site not only slowed diffusion and hindered grain growth but also increased oxygen vacancies by creating additional gas transmission channels. The gradual decrease in carrier mobility with increasing entropy resulted in the degradation of electrical conductivity, while the Seebeck coefficient experienced a large enhancement due to band modification and increased carrier scattering. Meanwhile, multiscale defects, including point defects, local strain fields, dislocations, and grain boundaries, effectively scatter phonons, leading to a low lattice thermal conductivity of 1.73 W·m-1·K-1. Consequently, the sample with x = 0.15 exhibited a peak ZT of 0.15 at 900 K, reflecting a 148% enhancement compared to that of the matrix. In addition, the hardness increases with configurational entropy because of the chemical disorder, grain refinement, and increased defect concentration. The work emphasizes the importance of precise manipulation of configurational entropy, offering valuable insights for optimizing thermoelectric materials through entropy engineering strategy.

Elastic conductivity of germanene nanoribbons with acceptor defects

This work is devoted to the theoretical researchers of the germanene nanoribbons piezoresistivity of various structural modifications (arm-chair and zig-zag) with the acceptor structural defects. Gallium atoms were chosen as impurities. A phenomenological expression for the band structure of nanoribbons deformed by tension and compression is proposed. The dependences of the longitudinal component of the elastic conductivity tensor on the relative deformation of tension and compression, the concentration of impurities and the width of the nanoribbon are analyzed.

Blue Luminescence from N-doped Graphene

Abstract Blue luminescence (BL) has been observed in various astrophysical environments, such as the inner region of the Red Rectangle Nebula. It has been previously linked to small polycyclic aromatic hydrocarbons. In this study, we explore the potential of N- and O-doped graphene material as carriers of BL. Using vacuum ultraviolet irradiation, pristine single-layer graphene films were exposed to solid N2 and O2 at low temperatures, resulting in the formation of N- or O-doped graphene. The photoluminescence (PL) spectrum of the synthesized N-doped graphene exhibits an asymmetrical peak at 378 nm, which is nearly identical to the BL observed in the Red Rectangle. In contrast, the synthesized O-doped graphene shows a symmetrical PL band at 414 nm. Further Raman and X-ray photoelectron spectroscopy analyses reveal that nitrogen atoms substitute carbon atoms in the graphene lattice, introducing structural defects and sp2 regions responsible for the observed luminescence. The simplicity of the bonding structures in the N-doped graphene, dominated by pyrrolic-N and pyridinic-N groups, further supports its potential as a model system for studying BL.

GeTe/Sb2Te3 Super‐Lattices: Impact of Atomic Structure on the RESET Current of Phase‐Change Memory Devices

AbstractPhase change memories (PCMs) are at the heart of modern memory technology, offering multi‐level storage, fast read/write operations, and non‐volatility, bridging the gap between volatile DRAM and non‐volatile Flash. The reversible transition between amorphous and crystalline states of phase‐change materials such as GeTe or Ge2Sb2Te5 is at the basis of PCM devices. Despite their importance, PCM devices face challenges including high power consumption during the RESET operation. Current research efforts focus on improving device architecture and exploring alternative phase‐change materials such as GeTe/Sb2Te3 super‐lattices (SLs), for which a reduced programming power consumption is observed compared with standard PCMs. Herein, by combining X‐ray diffraction and scanning transmission electron microscopy imaging of SL thin films with the study of the same SL in PCM devices, it is shown that it is possible to significantly decrease RESET energy of the device, without modifying the SL composition, by reducing the amount of structural defects through annealing treatment. The best device properties are obtained after transforming the SL into a defect‐free, highly out‐of‐plane oriented rhombohedral phase. These results offer a promising avenue for further improving the performance of SL‐based PCM devices through structural optimization.

Bottom‐Up Strategy to Enhance Long‐Range Order of Poly(Heptazine Imide) Nanorods for Efficient Photocatalytic CO2 Methanation

AbstractPoly(heptazine imide) (PHI), one of the crystalline or long‐range ordered allotropes of polymeric carbon nitride, is a promising polymeric photocatalyst; however, preparation of highly crystalline PHI remains a challenge. Herein, through a bottom‐up strategy involving repair of structural defects and increase of specific surface area of melon precursor, we prepared PHI nanorods with dramatically improved long‐range order. The resulting PHI exhibited a shift of product selectivity in CO2 photoreduction from CO to CH4 with a high methanation activity in contrast to the pristine PHI with relatively low long‐range order. The improvement of long‐range order for PHI remarkably enhanced the separation efficiency and transfer kinetics of photogenerated charges as well as the adsorption for *CO intermediate. This study revealed the relationship between the precursor structure and PHI crystal growth in ionothermal synthesis, and also showcased the great potential of highly crystalline PHI in artificial photosynthesis.

Combination of Biochar and Advanced Oxidation Processes for the Sustainable Elimination of Pharmaceuticals in Water

The presence of pharmaceuticals in aquatic ecosystems is an issue of increasing concern. Regardless of the low concentration of pharmaceuticals in water, they can have a toxic effect on both humans and aquatic organisms. Advanced oxidation processes (AOPs) have been described as a promising technique for eliminating pharmaceuticals due to their high efficiency. However, the cost associated with the application of these processes and their high reagents and energy requirements have affected the implementation of AOPs at large scales. Biochar has been suggested to be used as a catalyst in AOPs to overcome these limitations. Biochar is considered as an alternative heterogeneous catalyst thanks to its physicochemical characteristics like its specific surface area, porous structure, oxygen-containing functional groups, electrical conductivity, persistent free radicals (PFRs), modifiable properties, and structure defects. This carbonaceous material presents the capacity to activate oxidizing agents leading to the formation of radical species, which are needed to degrade pharmaceuticals. Additionally, AOP/biochar systems can destroy pharmaceutical molecules following a non-radical pathway. To enhance biochar catalytic performance, modifications have been suggested such as iron (Fe) impregnation, heteroatom doping, and supporting semiconductors on the biochar surface. Although biochar has been efficiently used in combination with several AOPs for the mineralization of pharmaceuticals from water, further research must be conducted to evaluate different regeneration techniques to increase biochar’s sustainable applicability and reduce the operational cost of the combined process. Moreover, operational conditions influencing the combined system are required to be evaluated to discern their effect and find conditions that maximize the degradation of pharmaceuticals by AOP/biochar systems.

Cristobalite Formation in Fused Quartz Crucibles for Czochralski Silicon Production in Different Conditions

Cristobalite is one of the quartz crystalline polymorphs that forms at above 1470 °C in its pure form and above 1000 °C for quartz glass. Its formation during the Czochralski process is therefore inevitable, and is usually controlled by doping the quartz sand with barium or barium-based coatings. The formation of cristobalite can lead to significant structural defects in silicon ingots. In this work, we studied the influence of various materials (graphite, silicon carbide and alumina) on the formation and properties of the cristobalite layer. In our study we investigated glass samples extracted from a commercially produced fused quartz crucible. The samples were heat-treated in different furnaces with different contact materials: alumina, silicon carbide and graphite. The furnace with alumina as contact material was an open-air furnace, while the two others were purged with argon. All of the heat treatment experiments lasted for 3 hours at a temperature of 1500 °C, which is the approximate temperature of the Czochralski process. After the heat treatment, the samples were investigated by light microscopy and X-ray diffraction. The results showed that the contact material is the most determining factor for the cristobalite layer’s thickness and morphology. The enhancement of cristobalite formation is the greatest by using graphite as the contact material, followed by alumina. Results indicate a retardation in phase transformation in comparison to other materials. These findings are an important step to further understanding of the cristobalite formation kinetics in fused quartz crucibles during the Czochralski process.

Clinical severity and cardiac phenotype in phosphomannomutase 2-congenital disorders of glycosylation : Insights into genetics and management recommendations.

Cardiac involvement (CI) in phosphomannomutase 2-congenital disorders of glycosylation(PMM2-CDG) is part of the multisystemic presentation contributing to high mortality rates. The most common cardiac manifestations are pericardial effusion, cardiomyopathy, and structural heart defects. A genotype-phenotype correlation with organ involvement has not yet been described. We analyzed clinical, biochemical, and molecular genetic data of 222 patients from eight European centers and characterized the natural course of patients with CI. Fifty-seven patients (45 children) presented with CI, of whom 24 died (median age 21 months, standard deviation 49.8). Pericardial effusion was the most frequent manifestation (55.4%), occurring mostly within the first 6 months of life. The most common pathogenic variants in patients with CI were p.(Arg141His) in 74%, followed by p.(Val231Met) in 36%, which is 3.5 times higher than in PMM2-CDG patients without CI (p < 0.0001). Twenty-one out of 36 patients with p.(Val231Met) had CI; among them, 15 died, compared to 33 out of 166 patients without p.(Val231Met) who had CI (p < 0.0001). Nine out of 33 patients died (p = 0.0015), indicating greater clinical severity. Furthermore, the p.(Val231Met) variant is predominant in Eastern Europe, suggesting a founder effect. Cardiac complications in PMM2-CDG patients are common and serious. The variant p.(Val231Met) profoundly influences the extent of CI and mortality rates. Therefore, we recommend cardiac surveillance be included in the follow-up protocols for PMM2-CDG.

Role of grain boundary passivation in the enhancement of efficiency of copper chalcogenides thin film photovoltaic devices: A schematic review

Photovoltaic devices are expected to display peak performance if fabricated with perfect single crystals. Since surfaces break the periodicity of a single crystal, there are regions of defects, which give rise to states inside the forbidden energy gap. In polycrystalline thin films, the main structural defect is the grain boundary. The presence of grain boundaries affects the optical absorption, carrier mobility and lifetime of the semiconductor. This review focuses on grain boundary passivation in thin film photovoltaic devices based on copper chalcogenides. Achieving enhanced performance in copper chalcogenide thin film Photovoltaic devices requires effective grain boundary passivation. This approach aims to mitigate the adverse effects of grain boundaries on the optoelectronic properties of the material, leading to improved efficiency and stability in Photovoltaic devices. The abstract discusses recent developments, methodologies and outcomes related to grain boundary passivation strategies, shedding light on their significance in advancing the performance of copper chalcogenide thin film Photovoltaic devices. The exploration of grain boundary passivation in this context contributes valuable insights to the ongoing efforts in optimizing the performance of thin film Photovoltaic technologies.

Hydride-Induced Reconstruction of Pd Electrode Surfaces: A Combined Computational and Experimental Study.

Designing electrocatalysts with optimal activity and selectivity relies on a thorough understanding of the surface structure under reaction conditions. In this study, experimental and computational approaches are combined to elucidate reconstruction processes on low-index Pd surfaces during H-insertion following proton electroreduction. While electrochemical scanning tunneling microscopy clearly reveals pronounced surface roughening and morphological changes on Pd(111), Pd(110), and Pd(100) surfaces during cyclic voltammetry, a complementary analysis using inductively coupled plasma mass spectrometry excludes Pd dissolution as the primary cause of the observed restructuring. Large-scale molecular dynamics simulations further show that these surface alterations are related to the creation and propagation of structural defects as well as phase transformations that take place during hydride formation.

Periapical cysts in dogs: 10 cases (2000-2020).

To characterize the clinical, diagnostic imaging, and histologic features with description of treatment outcome of periapical cysts in dogs. Ten client-owned dogs diagnosed with periapical cysts biopsied between July 1, 2000 and June 30, 2020. Medical records of the Matthew J. Ryan Veterinary Hospital of the University of Pennsylvania were retrospectively searched to identify dogs that had surgical biopsy specimens of cavitary lesions diagnosed as odontogenic cysts and that met additional inclusion criteria. Complete medical records were reviewed. Range age and body weight of affected dogs were 2.5-12.1 years and 4.3-38.4 kg (9.5-84.7 lb), respectively. All periapical cysts were affecting the incisive bone and/or the maxilla. Nine dogs presented with a fluctuant swelling of the oral mucosa and gingiva; one dog without clinical swelling presented with a history of difficulty breathing. All cysts originated from a non-vital tooth with a structural defect (wear or fracture without pulp exposure) and/or intrinsic staining. Extraction of the associated non-vital teeth, enucleation of the cysts, and curettage of the surgical sites resulted in resolution of the clinical signs. The findings indicate that periapical cysts are associated with a non-vital tooth without pulp exposure. Complete evaluation of the clinical, diagnostic imaging, and histologic features of the lesion in affected dogs is necessary to differentiate periapical cysts from other odontogenic cysts and tumors.

Net-shaping (Y,NSG)BCO composite superconductor into cylindrical geometry with enhanced flux pinning up to 9 T at 77 K

Abstract Fabrication of a (Y,RE)BCO superconducting compact simultaneous with improved properties is demonstrated using gelcasting of slurries into rapid prototyped precision moulds. The infiltration Growth (IG) process with NdBCO film seed was used to obtain a textured 45 mm long hollow superconducting (Y,RE)BCO cylinder, as a prototype. This involves design of a (Y,RE)2BaCuO5 preform referred to as (Y,RE)-211, into which liquid phase is infiltrated; this reacts with the preform and forms (Y,RE)Ba2Cu3O7-x. The end product aimed at is a composite of YBa2Cu3O7-x (YBCO) with 20 wt% of mixed rare earth (Nd,Sm,Gd)BCO and 0.5 wt% of WO3 nanoparticles, which are intended to cause notable enhancement in flux pinning and critical current density (J c). Uniform distribution of micron-sized (Y/RE)-211 and WO3 nanoparticles in the matrix was enabled by sol-casting process. Magnetic shielding is demonstrated at low dc fields (41 gauss). J c is found to remain nearly constant with field (B) at each temperature (T) up to 50 K, where J c reaches about 4 kA cm−2 at 8.5 T. At 77 K, J c of ∼ 4 kA cm−2 at zero field and ∼ 0.4 kA cm−2 at 8.5 T is observed. The flux pinning force density (F p) increased with the applied field, reaching a maximum at a field (B p) of 7 T to 8 T for all temperatures from 10 K to 77 K. Temperature-independent B p confirms that flux pinning is caused by structural defects that induce fluctuations in the Ginzberg-Landau parameter (k). Substitution of RE ions randomly at the Y-site in YBCO unit cells can locally create compositional fluctuations that lead to stress fields and a dense network of stacking faults and assist pinning of flux. Analysis of F p (B) by scaling laws does confirm δk pinning to be the dominant mechanism. A second peak observed in F p(B) curves at low fields, below 3 T, is attributed to additional pinning from WO3 nanoparticles and is field-dependent. Significance of the present process stems from the fact that it enables uniform distribution of second phase additions to be realized in the end product, for improved performance and it allows design and creation of components of composite ceramic superconductor in any complex shape, required for a chosen application.

Bottom-Up Strategy to Enhance Long-Range Order of Poly(Heptazine Imide) Nanorods for Efficient Photocatalytic CO2 Methanation.

Poly(heptazine imide) (PHI), one of the crystalline or long-range ordered allotropes of polymeric carbon nitride, is a promising polymeric photocatalyst; however, preparation of highly crystalline PHI remains a challenge. Herein, through a bottom-up strategy involving repair of structural defects and increase of specific surface area of melon precursor, we prepared PHI nanorods with dramatically improved long-range order. The resulting PHI exhibited a shift of product selectivity in CO2 photoreduction from CO to CH4 with a high methanation activity in contrast to the pristine PHI with relatively low long-range order. The improvement of long-range order for PHI remarkably enhanced the separation efficiency and transfer dynamics of photogenerated charges as well as the adsorption capacity for *CO intermediate. This study revealed the relationship between the precursor structure and PHI crystal growth in ionothermal synthesis, and also showcased the great potential of highly crystalline PHI in artificial photosynthesis.

Point defects in complex inorganic compounds, spinel inverted, Kirkendall ‒ Frenkel effects

New technologies require new materials. One of the ways to find such materials are normal, reversed and partially reversed materials, which are used in spinels. Some such compounds are considered in oxygen-containing spinels, in particular, magnetic materials. Spinel inversion often results in structural defects, including antistructural exchange of cations. The preparation of solid solutions in aluminamagnesia spinel and mullite, which are not presented in the phase diagram, but have a higher diffusion mass transfer coefficient during the synthesis of a complex oxide, is considered. For spinel it is MgO, for mullite it is SiO2. For this, additives and the Kirkendall ‒ Frenkel effect were used. So far, there is no complete certainty that these are not composites, in which a material with a high diffusion mass transfer coefficient is distributed in a matrix of the main complex oxide (MgO·Al2O3, or 3Al2O3·2SiO2). The application of these approaches can expand the scope of materials for various applications.

Enhancing mechanical properties of PLA‐based bio composite filament reinforced with horse gram filler for 3D printing applications

AbstractGreen composites for 3D printing have gained significant attention due to the potential of incorporating natural fillers to reduce costs and enhance performance while maintaining environmental benefits. The use of agricultural by‐products, such as horse gram (Hg), not only promotes waste utilization but also seeks to improve the mechanical properties of biopolymers like PLA. In this study, Hg powder was utilized as a natural filler to enhance the mechanical properties of PLA‐based composites. The composites were fabricated with 1%, 2%, 3%, and 4% Hg powder filler content, and the filament was processed through a single screw extruder machine. Their mechanical properties were systematically evaluated to determine the optimal filler ratio. The results indicate that the incorporation of 1% Hg filler into PLA provided superior mechanical performance compared to Neat PLA. Specifically, tensile strength increased by 11.19%, flexural strength improved by 5.32%, and compression strength increased by 5.94%. In contrast, composites with 2% and 3% Hg filler showed a reduction in these mechanical properties, highlighting that the 1% Hg/PLA composite achieves the best balance between strength and filler content. The findings suggest that the 1% Hg/PLA composite offers an optimized combination of tensile, flexural, and compression properties, making it a strong candidate for environmentally sustainable engineering applications such as lightweight structural components, automotive interior parts, and consumer product casings.Highlights One percent Hg filler improved tensile, flexural strength, and hardness through uniform dispersion. Higher filler content (3%–4%) led to agglomeration, reducing composite performance. XRD and SEM analyses revealed reduced PLA crystallinity and structural defects at higher filler levels.

Morphological and agronomic features of potato cv. Gardena highly resistant to Phytophthora infestans (Mont.) de Bary depending on the nitrogen dose

In a 2-year field study, the impact of mineral nitrogen fertilization on the productivity of a new potato cultivar, promising due to the highest resistance to potato late blight among the registered ones, was compared to the proven, widely cultivated Denar cultivar. The study determined morphological features (size and weight of organs), physiological indicators (cover of soil by leaves – LAI. leaf greenness – SPAD) of potato plants during the growing season, yield and quality characteristics of tubers and optimal level of nitrogen fertilization. Tuber quality was assessed based on the share of tuber size and external defects in the yield structure. Optimal mineral nitrogen fertilization was determined based on the relationship between the increase in tuber yield and the increasing dose of this ingredient. The research took into account two factors: nitrogen dose (0, 50 kg‧ha–1, 100 kg‧ha–1, 150 kg‧ha–1) and cultivar (Gardena and Denar). The increase in the dose of mineral nitrogen fertilization to 150 kg‧ha–1 resulted in a significant increase in plant height, the weight of the root system, stems, leaves and the share of large tubers in the yield. It was shown that the Gardena cultivar was characterized by greater requirements for mineral nitrogen fertilization, low effectiveness of its use, a higher share of large tubers (diameter above 60 mm) and lower tuber yield than the Denar cultivar. In a year characterized by excess rainfall, plants produced a greater mass of the root system and the mass of the above-ground part, and in a year with an amount of rainfall close to optimal the final yield of tubers and the share of large tubers in the yield were higher.

Three-dimensional nanocomposites derived from combined metal organic frameworks doped with Ce, La, and Cu as a bifunctional electrocatalyst for supercapacitors and oxygen reduction reaction

Fabrication of a nanocomposite with a low-cost and efficient synthesis method instead of using electrocatalysts based on platinum metal has become one of the main challenges in energy storage devices and fuel cells. In this regard, a bifunctional electrocatalyst for supercapacitors and oxygen reduction reaction is fabricated and tested. The novelty of this study is the synthesis method and enhancement of the electrochemical characteristics of synthesized electrocatalysts. The core-shell method is used for the electrocatalyst's synthesis which uses Zeolitic Imidazolate Framework (ZIF)-8, ZIF-67, and Material Institute Lavoisiers (MIL)-101 for the fabrication of three types of electrocatalysts. In the following, to increase the characteristics such as conductivity and stability, doping of Copper (Cu), Cerium (Ce), and Lanthanum (La) are added to the nanocomposites. The Co@NC, CoZn@NC, and CoZn@FeNC prepared electrocatalysts are obtained from the pyrolyze process of La/ZIF-67, CeCu/ZIF-8@ La/ZIF-67, MIL-101@CeCu/ZIF-8/La/ZIF-67. The results indicated that the CoZn@NC electrocatalyst has the best performance in the oxygen reduction reaction (ORR) with an onset potential of 0.062 (V vs Ag/AgCl) and current density of −12.97 (mA/cm2) at a constant voltage of −1 V. Furthermore, the electron transfer number of CoZn@NC electrocatalyst for ORR was 3.64. The conducted Galvanostatic Charge-Discharge (GCD) tests demonstrated that the CoZn@NC electrode has the highest capacitance of 271.14 F/g. The outcomes showed that by the core-shell method, various properties of nanocomposites can be utilized to solve the weaknesses of catalysts by using proper metals. Moreover, the presence of Cu2+,Ce3+,La3+ improve the structural defects in the carbon matrix, the stability based on the chronoamperometry results, and the mass transfer. The study provides a perspective for future researches to fill the research gaps to obtain the new supercapacitors utilize on a large scale in the electronics industry.

Engineering the structure defects of ceria-zirconia-praseodymia solid solutions for diesel soot catalytic elimination

Creating structure defects in ceria-based solid solution catalysts is a crucial yet challenging task. Herein, urea-assisted synthesis strategy was designed for ceria-zirconia-praseodymia catalyst (CeZrPrOx) to create lattice defects; its effects on catalyst structure, physical-chemical properties and catalytic diesel soot purification activity were systematically investigated. Raman and X-ray photoelectron spectroscopy (XPS) findings indicate that the urea-assisted synthesized catalyst (CeZrPrOx-U) has remarkably more Ce3+ proportion (structure defects), oxygen vacancies and surface reactive oxygen species (O22- and O2-). Temperature-programmed reduction by hydrogen (H2-TPR) and temperature-programmed desorption by oxygen (O2-TPD) results further prove that the oxygen migration of the CeZrPrOx-U is definitely enhanced. Compared to the conventional CeZrPrOx catalyst, the bulk lattice oxygen of the CeZrPrOx-U can be migrated to the surface to generate surface reactive oxygen species more easily. As a consequence, the prepared CeZrPrOx-U catalyst exhibits obviously better catalytic diesel soot purification activity. Therefore, this study suggests that engineering the structure defects in CeZrPrOx catalyst is an effective approach to improve physical-chemical properties and enhance the soot catalytic elimination activity of the catalyst.