Amount Of Doping Research Articles

Multi boron-doping effects in hard carbon toward enhanced sodium ion storage

Hard carbon (HC) has been considered as promising anode material for sodium-ion batteries (SIBs). The optimization of hard carbon’s microstructure and solid electrolyte interface (SEI) property are demonstrated effective in enhancing the Na+ storage capability, however, a one-step regulation strategy to achieve simultaneous multi-scale structures optimization is highly desirable. Herein, we have systematically investigated the effects of boron doping on hard carbon’s microstructure and interface chemistry. A variety of structure characterizations show that appropriate amount of boron doping can increase the size of closed pores via rearrangement of carbon layers with improved graphitization degree, which provides more Na+ storage sites. In-situ Fourier transform infrared spectroscopy/electrochemical impedance spectroscopy (FTIR/EIS) and X-ray photoelectron spectroscopy (XPS) analysis demonstrate the presence of more BC3 and less B–C–O structures that result in enhanced ion diffusion kinetics and the formation of inorganic rich and robust SEI, which leads to facilitated charge transfer and excellent rate performance. As a result, the hard carbon anode with optimized boron doping content exhibits enhanced rate and cycling performance. In general, this work unravels the critical role of boron doping in optimizing the pore structure, interface chemistry and diffusion kinetics of hard carbon, which enables rational design of sodium-ion battery anode with enhanced Na+ storage performance.

Biocompatibility and antimicrobial efficacy of silver-doped borosilicate bioactive glass for tissue engineering application

Borate bioactive glasses are an auspicious material for tissue engineering applications due to their enhanced dissolution rate, bioactivity, and capacity to integrate therapeutic ions. In this study, borate-based S49B4 bioactive glass doped with silver at mass fraction of 0.5, 1, and 3 wt% were studied for bioactivity, degradation, antibacterial, and cytocompatibility. Thermogravimetric analysis revealed that the bioactive glasses were thermally stable between 600 and 700 °C. Fourier transform infrared spectroscopy and X-ray diffraction confirmed the successful synthesis of an amorphous phase of the doped borosilicate bioactive glasses and the incorporation of silver ion crystals within the structure, as well as associated contributions from borate and silicate network formers in the borosilicate bioactive glass. Morphological evaluation revealed that the borosilicate bioactive glasses exhibit a uniform and spherical shape across all formulations, with the mean particle size varying from 65 to 76 nm. An in-vitro acellular bioactivity in simulated body fluid medium showed that increasing the silver content increased the degradation rate and pH. Besides, scanning electron microscopy and Energy dispersive X-ray spectroscopy analysis revealed an upsurge in apatite production on the BBGs' surfaces as well as incremental Calcium-Phosphate ratio values of 1.50, 1.65 and 1.70 as the silver content increases. The antibacterial effect was tested against Escherichia coli and Staphylococcus aureus, while cytocompatibility was tested against human gingival epithelial cells. Silver integration at 1 wt percent yielded the most promising outcomes, which were particularly bactericidal at 79.8 % for Escherichia coli and 93.41 % for Staphylococcus aureus. Similarly, its Lactate Dehydrogenase percentage is significantly similar to the negative control employed in the study, indicating its biocompatibility. In contrast, 3 wt% silver exhibited the maximum bactericidal activity while also exhibiting mild cytotoxicity. In summary, our research indicates that elevated silver concentration enhances the bioactivity and antimicrobial characteristics of borosilicate bioactive glasses; nevertheless, a higher silver weight percent in this study also increases the possibility of cytotoxicity. It is therefore essential to carefully regulate the amount of silver doping at lower concentrations in order to maximize antibacterial action and minimize toxicity to human cells. The results presented here contribute to our understanding of the prospective use of silver doped borosilicate bioactive glasses as a possible material for tissue engineering applications.

Enhancing CO2 methanation via doping CeO2 to Ni/Al2O3 and stacking catalyst beds

This work synthesized a series of Ni/CeO2/Al2O3 catalysts with varying CeO2 doping amounts to enhance low-temperature CO2 methanation. The introduction of CeO2 weakens the interaction between Ni and Al2O3, leading to the formation of Ni-CeO2 active sites. This results in a high dispersion of Ni and CeO2, improved catalyst reducibility, increased number of active sites, and enhanced the CO2 methanation. This work further investigated the impact of WHSV and catalyst stacking configuration to enhance the reaction. When the catalyst is stacked into three segments with a temperature gradient of 330 °C, 300 °C, and 250 °C under WHSV = 9000 ml·h–1·(g cat)−1, the CO2 conversion significantly increases to 95%, which is remarkably close to the thermodynamic equilibrium (96%).

Improved Alkaline Hydrogen Evolution Performance of Dealloying Fe75-xCoxSi12.5B12.5 Electrocatalyst.

The electrocatalytic performance of a Fe65Co10Si12.5B12.5 Fe-based compounds toward alkaline hydrogen evolution reaction (HER) is enhanced by dealloying. The dealloying process produced a large number of nanosheets on the surface of NS-Fe65Co10Si12.5B12.5, which greatly increased the specific surface area of the electrode. When the dealloying time is 3 h, the overpotential of NS-Fe65Co10Si12.5B12.5 is only 175.1 mV at 1.0 M KOH and 10 mA cm-2, while under the same conditions, the overpotential of Fe65Co10Si12.5B12.5 is 215 mV, which is reduced. In addition, dealloying treated electrodes also show better HER performance than un-dealloying treated electrodes. With the increase in Co doping amount, the overpotential of the hydrogen evolution reaction decreases, and the hydrogen evolution activity is the best when the addition amount of Co is 10%. This work not only provides a basic understanding of the relationship between surface activity and the dealloying of HER catalysts, but also paves a new way for doping transition metal elements in Fe-based electrocatalysts working in alkaline media.

Performance and mechanism of electrocatalytic oxidation of urea based on carbon-doped FeCoNiCrMn high entropy alloy film

The application and research of high entropy alloy electrodes in urea oxidation reactions (UOR) are significant. In this study, FeCoNiCrMn, FeCoNiCrMnO, and FeCoNiCrMnC high entropy alloy thin films were prepared by magnetron sputtering by controlling the sputtering power, varying the sputtering atmosphere, and using double target co-sputtering, respectively. The microstructure and surface morphology of the electrode were observed and analyzed by X-ray diffraction, scanning electron microscope, transmission electron microscope, and atomic force microscope. In addition, the chemical state of the elements on the electrode surface was analyzed by X-ray photoelectron spectroscopy (XPS) to clarify the mechanism related to the excellent UOR performance of the electrode. The study found that a small amount of carbon doping can greatly improve the UOR performance of this type of electrode. The amorphous FeCoNiCrMnC electrode has more potential UOR active sites than the face-centered cubic FeCoNiCrMn electrode. After cyclic voltammetry (CV), the potential active sites of the electrode are activated, and the active substances of these electrodes are increased, furthermore, the UOR performance of these electrodes has improved. Since it has 200 cycles of CV, the 10 mA cm−2 potential of FeCoNiCrMnC electrode for UOR is only 1.337 V. After 100 days of natural aging, the catalytic ability of the electrode not only did not decrease but slightly improved, with a potential of 1.321 V at 10 mA cm−2, reflecting the good stability of the catalytic electrode.

Effects of Y3+ doping on the microstructure evolution, optical, dielectric, and non-Ohmic properties of Na1/3Cd1/3Bi1/3Cu3Ti4O12 ceramics

In this study, Na1/3Cd1/3(Bi1-xYx)1/3Cu3Ti4O12 (NCBYCTO, x = 0−0.20) ceramics were successfully prepared via solid state method. Their microstructure along with the optical, dielectric, and non-Ohmic properties were investigated systemically. It was shown that Y3+ doping caused the decrease in cation vacancy concentration and the increase in optical energy band. With the increase of Y3+ content, ceramics exhibited a more stable structure, while their average grain size increased from 6.80 μm to 9.12 μm and then decreased to 2.17 μm with the dopant amount. The relative density increased from 94.7 % for the undoped specimen to 95.6 % for the specimen with x = 0.20. The giant dielectric constant (ɛ′ = 44200) at a relatively low dielectric loss (tanδ = 0.048) at 10 kHz was obtained in the specimen with x = 0.08, being more than three times that of undoped sample and demonstrating the outstanding frequency stability in the range of 40−106 Hz. The giant dielectric constant below 106 Hz originated from Maxwell–Wagner relaxation related to the insulating grain boundaries (GBs) and followed the internal barrier layer capacitor model. Besides that, Y3+ doping improved the nonlinearity properties of NCBYCTO ceramics. The specimen with x = 0.20 had the largest nonlinearity coefficient α (∼9.60) and breakdown field strength Eb (∼7.15 kV/cm). At last, the nonlinear J-E characteristics were closely related to the GB conductivity activation energy.

Controllable synthesis of NiCoMo-LDH with nanofloral structure assisted by monodisperse spherical silica for asymmetric supercapacitor

Traditional layered double hydroxides (LDH) have disadvantages such as small layer spacing, insufficient active sites and poor electrical conductivity, which seriously restricts their future utilization in the realm of energy storage. In this paper, a controlled synthesis strategy of tercomponent metal NiCoMo-LDH is proposed by using the structural advantages of metal-organic skeleton (MOF) templates, combining structural regulation and atom doping. On the basis of the synthesis of Ni-MOF 74, Co and Mo atoms are introduced for a small amount of doping, and the monodisperse spherical SiO2 is inserted to adjust the pore structure of NiCoMo-MOF, expand the lamellar spacing, and effectively avoid the accumulation and agglomeration of lamella. Finally, NiCoMo-LDH cathode material with loose porous and coarsely curled nanosphere structure was synthesized through the chemical reaction of OH− with SiO2 and the destruction of the skeleton structure of MOF. The specific capacitance of the material is 1423.3 F·g−1 at 0.5 A·g−1, and after 5000 cycles of charging and discharging, 80.0% of the original specific capacitance is sustained. Moreover, NiCoMo-LDH//AC ASC possesses a high energy density of 39.1 Wh·kg−1 at the power density 400 W·kg−1. Combined with density functional theory (DFT) calculation, the fact that metal doping can not only effectively improve the conductivity of electrode materials has been further proved, but also accelerate the electron/ion migration rate, which successfully reveal the synergistic enhancement mechanism of electrochemical properties of materials.

Oxidation of 5-Hydroxymethylfurfural into 2,5-Diformylfuran on Alkali Doped Ru/C Catalysts. Electron Properties of Ruthenium Species as Descriptor of Catalytic Activity.

Selective aerobic oxidation of 5-hydroxymethylfurfural into 2,5-diformylfuran has been achieved on alkali doped Ru/C catalyst. Optimization of Ru metal nanoparticles, as well as the nature and amount of the alkali dopant have been performed. The results showed that doping the Ru/C catalyst with controlled amount of potassium increases the catalytic activity, 2.5 fold with respect to the non-doped sample. Spectroscopic studies showed that these differences in activity can be attributed to a different oxidation reaction mechanism associated to the presence of electron rich Ru species in the promoted sample that facilitate the dissociation of O2, while prevents the oxidation of the metal. The Ru/C-K doped catalyst resulted very stable against leaching and metal sintering, being possible the reuse over several consecutive runs. Moreover, the catalyst could be successfully applied to the oxidation of different alcohols.

Effective strategy for Cr(VI) removal from water in evolution process of ferroan brucite by redox and intercalation

Cr(VI)-contaminated wastewater treatment is of great significance to ecological environment and human health. In this work, ferroan brucite with different Fe2+ doping amounts (Mg1-XFeX(OH)2, x = 0.1–0.8) were synthesized for the removal of Cr(VI) from wastewater. The effect of Fe content, initial concentration of Cr(VI), reaction time, co-existing ions and pH for Cr(VI) removal performance were examined. As Fe2+ content increased, the removal efficiency initially increased and then decreased, Mg0.4Fe0.6(OH)2 exhibited the maximum removal amount of 494.63 mg/g. Kinetic studies showed Cr(VI) removal well fitted pseudo-second-order model and achieved equilibrium at approximately 40 min. Isotherm data was well described by Langmuir model. The coexisting ions except CO32− had negligible effect, while pH had a significant influence on Cr(VI) removal since different dominated form of Cr(VI) existed at different pH. The removal mechanism towards Cr(VI) under different pH values was explored. At acidic environment, most Cr(VI) in Cr2O72− was reduced to Cr(III) by Fe2+ resulting in the precipitation of (Fe,Mg)(Cr,Fe)2O4, the remaining part was immobilized by interlayer of reaction product LDHs, and the intercalation amounts of Cr2O72− were 114.05 mg/g and 106.78 mg/g at pH of 3 and 6. While under alkaline conditions, most CrO42− entered the interlayer of LDHs with amounts of 262.3 mg/g at pH = 11, and the rest was absorbed on the surface. Furthermore, the reaction product could be recovered as chromite with recovery rate of 83.94 %. The excellent removal performance suggested a promising strategy in sewage water remediation.

The effect of rare earths (Nd3+, Er3+, Yb3+) additives on the radiation shielding properties of the tungsten oxide modified tellurite glasses

Abstract In this study, we have reported on the effect of the rare earth oxides on the radiation protection performance of the tellurite glasses. In order to determine the effect of rare earth oxides on the radiation shielding properties of tungsten oxide (WO3) modified tellurite glasses, three rare earth element oxides (Nd2O3, Yb2O3, and Er2O3) have been selected. The glass systems have been synthesized using the traditional melt quenching method and were doped with the different amount (1 %, 3 %, 5 %) of the oxides of rare earth elements (Nd2O3, Yb2O3, Er2O3). The linear attenuation coefficient, mass attenuation coefficient, half value layer, and effective atomic number of the synthesized samples were experimentally measured for 662, 1,173 and 1,332 keV gamma-ray energies which were emitted from 137Cs and 60Co radioactive sources. Measurements were conducted in narrow beam transmission geometry using a NaI(Tl) scintillation detector. In addition, all these parameters were calculated theoretically using the WinXCOM program in the energy region of 0.015–15 MeV. The addition of different types and amounts of rare earth oxides to the tellurite glass system was found to significantly enhance the radiation protection performance of the glasses. In particular, it was found that the radiation shielding characteristics of the glasses improved with increasing amount of rare earth doping, the TWYb5 glass system had the best radiation shielding properties, and there was a trend among the doped rare earth oxides in the form of Yb > Er > Nd according to their radiation shielding performance.

Size-strain distribution analysis from XRD peak profile of (Mg, Fe) co-doped SnO2 nanoparticles fabricated using chemical co-precipitation route

In this study, we synthesize pristine and (Mg, Fe) co-doped SnO2 nanoparticles using the chemical co-precipitation method, where the Mg doping amount is fixed (2 mol%) and the amount of Fe is varied between 2 and 6 mol%. The narrow and sharp natures of intense XRD peaks notify that the crystallinity is pretty well. The formation of the single-phase tetragonal rutile type structure of all prepared compounds has been identified by Rietveld refinement, Fourier-transform infrared spectroscopy (FTIR), and Raman spectroscopy. Moreover, the well incorporation of Fe and Mg in SnO2 and absence of any other unexpected elements are confirmed by the energy dispersive X-ray spectroscopy. How the co-doping of Mg and Fe alter the crystallite size, microstrain, and dislocation density of the prepared samples have been investigated by Scherrer method with various modified version of it, Williamson-Hall method (W–H) in three factions (UDM, USDM, and UDEDM), Size strain plot (SSP) method, Halder-Wagner (H–W) method, Wagner-Aqua (W-A) method, and Warren-Averbach (WA) method. The obtained crystallite size using the WA method is smaller than the other methods and Scherrer-based methods show much comparable (except SLMSE) sizes. Additionally, the W–H, H–W, SSP, and W-A plots show almost similar tendency of decreasing crystal size, increasing dislocation density and lattice strain with increasing doping. The scanning electron microscopy (SEM) profiles revealed that the synthesized nanoparticles are agglomerated in nature, where the agglomeration increases with decreasing crystal size. The magnetic response of the prepared samples revealed a weak ferromagnetic (or soft magnetic) nature, where saturation magnetization increased due to doping, and a reducing trend of remanent magnetization and coercivity was explored which indicates the phase transition from ferromagnetic to paramagnetic. However, this soft magnetic nature was modified with the influence of defects like changes in lattice parameters, strain, and oxygen vacancy. This phase transition at higher doping concentration makes our nanomaterial as a suitable contender for memory devices, hyperthermia treatment, and photothermal effect.

Solution combustion derived color-tunable Eu3+ doped Ca8ZnBi(VO4)7 nano sample for luminous devices and latent fingerprinting applications

Eu3+ doped Ca8ZnBi(VO4)7 host lattice have been produced through an environmentally friendly, economical, and energy-efficient solution combustion synthesis. The trigonal phase with the R 3c space group of the constructed series was verified by x-ray diffraction and Rietveld refinement technique. The elemental and morphological study was done by using energy dispersive X-ray analysis (EDAX) and scanning electron microscope (SEM), transmission electron microscope (TEM) respectively. In the excitation spectra, the intense band at 334 nm indicates the transfer of energy occur between VO43- → Eu3+. The color-tunable features of the generated nanosample are indicated by the emission (617 nm, 5D0→7F2) color of the nanophosphor, which lies in the yellow, orange, and red regions for varying doping amounts. The band gap was determined using Tauc’s hypothesis for both host lattice (3.18 eV) and Eu3+ doped nanomaterials (3.13 eV) which lie in the range of semiconductors. The use of Dexter’s theory and the Inokuti-Hirayama (I-H) model verified the existence of dipole–dipole (d-d) type interlinkages as a genuine phenomenon for concentration quenching. Additionally, Auzel’s system was used to study radiative lifetime (0.6510 ms), quantum efficiency (59.51 %), and non-radiative rates (621.8 s−1). The CIE coordinates (0.5164, 0.4703), lower value of correlated colour temperature (CCT) (2459 K) and color-tunable phenomena made it a possible choice for warm white light emitting luminous devices. The optimized nanophosphor has been investigated for latent fingerprinting and has been successful in identifying all of the fingerprint’s levels-1, 2 and 3.

Microstructure evolution, dielectric properties, and nonlinear response of Na+-doped CdCu3Ti4O12 ceramics.

In this study, Cd1-x Na x Cu3Ti4O12 (x = 0, 0.02, 0.04, 0.06, and 0.08) ceramics were prepared via a solid-state method. The phase composition, microstructure, and defect characteristics as well as optical, dielectric, and nonlinear properties of the ceramics were systematically studied. A CuO second phase was detected in doped samples. Grain boundary precipitates, Na with a low melting point, and oxygen and cation vacancies together caused the grain size to first increase and then decrease with an increase in the Na+ doping amount. The abundant emerging cation vacancies with an increase in Na+ content led to a decrease in the optical energy band. The sample with x = 0.04 exhibited the highest ε' value (∼35 800) due to its largest grain size. Moreover, it possessed a lower tan δ (∼0.053) at 10 kHz, which was attributed to the multiplication of insulating grain boundaries. The huge dielectric constant originated from Maxwell-Wagner polarization at low frequencies and followed the internal barrier effect model. The lowest tan δ (∼0.037) and optimal nonlinear properties (α = 3.66 and E b = 3.82 kV cm-1) were obtained in the sample with x = 0.08, which were associated with its highest grain boundary resistance and barrier height. Electric modulus data proved that dielectric relaxation at low frequencies was associated with grain boundaries. Dielectric anomalies in the high temperature range were attributed to oxygen vacancies.

In-situ Ti4+-doped modification of layer-structured Ni-rich LiNi0.83Co0.11Mn0.06O2 cathode materials for high-energy lithium-ion batteries

The further commercialization of layer-structured Ni-rich LiNi0.83Co0.11Mn0.06O2 (NCM83) cathode for high-energy lithium-ion batteries (LIBs) has been challenged by severe capacity decay and thermal instability owing to the microcracks and harmful phase transitions. Herein, Ti4+-doped NCM83 cathode materials are rationally designed via a simple and low-cost in-situ modification method to improve the crystal structure and electrode–electrolyte interface stability by inhibiting irreversible polarizations and harmful phase transitions of the NCM83 cathode materials due to Ti4+-doped forms stronger metal-O bonds and a stable bulk structural. In addition, the optimal doping amount of the composite cathode material is also determined through the results of physical characterization and electrochemical performance testing. The optimized Ti4+-doped NCM83 cathode material presents wider Li+ ions diffusion channels (c = 14.1687 Å), lower Li+/Ni2+ mixing degree (2.68 %), and compact bulk structure. The cell assembled with the optimized Ti4+-doped NCM83 cathode material exhibits remarkable capacity retention ratio of 95.4 % after 100cycles at 2.0C and room temperature, and outstanding reversible discharge specific capacity of 148.2 mAh g−1 at 5.0C. Even under elevated temperature of 60 °C, it delivers excellent capacity retention ratio of 92.2 % after 100cycles at 2.0C, which is significantly superior to the 47.9 % of the unmodified cathode material. Thus, the in-situ Ti4+-doped strategy presents superior advantages in enhancing the structural stability of Ni-rich cathode materials for LIBs.

Investigation of Piezoelectric Properties in Ca-Doped PbBa(Zr,Ti)O3 (PBZT) Ceramics.

The perovskite-structured materials Pb0.75Ba0.251-xCax(Zr0.7Ti0.3)O3 for x = 1 and 2 at.% were synthesized using the conventional mixed-oxide method and carbonates. Microstructural analysis, performed using a scanning electron microscope, revealed rounded grains with relatively inhomogeneous sizes and distinct grain boundaries. X-ray diffraction confirmed that the materials exhibit a rhombohedral structure with an R3c space group at room temperature. Piezoelectric resonance measurements were conducted to determine the piezoelectric and elastic properties of the samples. The results indicated that a small amount of calcium doping significantly enhanced the piezoelectric coefficient d31. The calcium-doped ceramics exhibited higher electrical permittivity across the entire temperature range compared to the pure material, as well as a significant value of remanent polarization. These findings indicate that the performance parameters of the base material have been significantly improved, making these ceramics promising candidates for various applications.

Metal Doped-MoS2/g-C3N4 Nanocomposites for Antibiotics Degradation with Photo-Fenton Reaction Process: Defect Engineering, Synergistic Effects, and Degradation Mechanisms

Currently, the energy crisis and environmental pollutions due to the growth of industrialization and urbanization become gradually a prominent and serious issue. Due to these reasons, we aimed to design photoactive metal-doped MoS2/g-C3N4 nanocomposites photocatalysts for the degradation of antibiotics. The degradation of organic pollutants with photocatalysis is considered as green, ecofriendly, economical, and promising methods. Herein, ultrathin g-C3N4 was prepared with simple method and combined with metal-doped MoS2 (Mg-doped MoS2) with varying the amounts of dopants. The prepared photocatalyst materials were tested for the degradation of ciprofloxacin in the photo-Fenton reaction process. The optimum amount of metal-doped MoS2/g-C3N4 nanocomposites photocatalysts showed enhanced catalytic performance and degrades 72% of ciprofloxacin while 52 and 48 % of degradations were achieved with MoS2 and g-C3N4 catalysts, respectively. Here, the key significant problems of the individual components were solved via synergistic effects in the photocatalytic degradation system. The results also offer an opportunity to enhance the electronic structures of the crystalline materials. Moreover, the metal-doping will also create defects on the MoS2 and improves the charge transfer ability of the photocatalyst. The results proved that the metal-doped MoS2/g-C3N4 nanocomposites photocatalysts could be a promising photo-Fenton catalyst system in the environmental remediation.

In-situ electrochemical interface of Cu@Ag/C towards the ethylene electrosynthesis with adequate *CO supply

The conversion of carbon dioxide to ethylene by electrochemical reduction (CO2RR) provides a new strategy for achieving carbon dioxide conversion. However, copper-based catalysts have the disadvantages of unsatisfactory selectivity and low current density, which limit the potential CO2RR industrial expansion. Researches have verified that the real reaction sites at the catalyst surface often undergo reconstruction during the reaction, therefore, understanding and utilizing this phenomenon is crucial for improving catalytic performance. In this work, we introduced additional Ag component into Cu@Ag/C tandem catalyst by in-situ electrochemical reconstruction of Cu2CO3(OH)2/AgCl/C precursor. This electro-reduced catalyst exhibits a C2H4 Faradaic efficiency of 50.41% in H-cell, and 58.03% in the flow cell, surpassing the counterparts of pure Cu and Ag, as well as the Cu-Ag homolog with separated interface. Moreover, it also provides a long-term stability of 21 h with the ethylene Faraday efficiency (FE) over 50%. The appropriate amount of Ag dopant into the Cu catalyst changes the electronic structure of Cu surface by the electron transfer from Cu to Ag, which distinctly enhances the binding energy of CO2 on the catalyst. Meanwhile, in-situ Raman results and theoretical calculation reveal that the introduction of silver increases the number of active sites and improves the coverage of *CO intermediate, thereby accelerating the kinetics of C–C coupling and reducing its energy barrier. The combination of cascade catalytic strategy and in-situ electroreduction interface provides potential applications for future artificial carbon balance.

Insight into the Role of Rb Doping for Highly Efficient Kesterite Cu2ZnSn(S,Se)4 Solar Cells.

Various copper-related defects in the absorption layer have been a key factor impeding the enhancement of the efficiency of Cu2ZnSn(S,Se)4 (CZTSSe) solar cells. Alkali metal doping is considered to be a good strategy to ameliorate this problem. In this article, Rb-doped CZTSSe (RCZTSSe) thin films were synthesized using the sol-gel technique. The results show that the Rb atom could successfully enter into the CZTSSe lattice and replace the Cu atom. According to SEM results, a moderate amount of Rb doping aided in enhancing the growth of grains in CZTSSe thin films. It was proven that the RCZTSSe thin film had the densest surface morphology and the fewest holes when the doping content of Rb was 2%. In addition, Rb doping successfully inhibited the formation of CuZn defects and correlative defect clusters and promoted the electrical properties of RCZTSSe thin films. Finally, a remarkable power conversion efficiency of 7.32% was attained by the champion RCZTSSe device with a Rb content of 2%. Compared with that of un-doped CZTSSe, the efficiency improved by over 30%. This study offers new insights into the influence of alkali metal doping on suppressing copper-related defects and also presents a viable approach for improving the efficiency of CZTSSe devices.

Thermoelectric properties enhancement and optimization of SnTe-based material with single doping: RSM-ANN approach

Tin Telluride (SnTe) stands out among semiconductor materials, drawing attention as an environmentally friendly alternative to conventional Lead Telluride (PbTe). This study explores the novel incorporation of titanium (Ti) and zirconium (Zr) as dopant elements in SnTe-based materials, an approach that has never been previously investigated. Leveraging mathematical modeling and machine learning methodologies, we use Response Surface Methodology (RSM) and Artificial Neural Network-Genetic Algorithm (ANN-GA) to predict thermoelectric properties of SnTe-based materials and find the optimum dopant element addition and operating temperature. Eleven samples featuring varying Ti and Zr concentrations are employed in experimental investigations, with dopant amounts ranging from 0 to 0.05 M. Characterization of each sample is conducted across a temperature spectrum from 50 to 450 °C, yielding a comprehensive dataset of 99 entries for neural network model construction. The generated RSM and ANN models demonstrate remarkable predictive accuracy for the thermoelectric properties of SnTe-based materials, showcasing coefficient of determination (R2) values spanning from 0.986 to 0.998. This study uses RSM and ANN-GA to predict an optimized zT value of 0.558. This value surpasses the highest zT value from the experiment by 3.33 %. In conclusion, this investigation underscores the potency of RSM and ANN as valuable tools for advancing research on SnTe-based thermoelectric materials, exemplifying their capacity to hasten the exhausting process of finding the optimum dopant addition and operating temperature.

Probing the thermophysical property mechanism of Mg2+-doped high-entropy oxide ceramics

To create thermal barrier coatings (TBCs) with superior thermal characteristics and high-temperature stability, understanding the microscopic process of heat transfer in high-entropy solid solutions is crucial. In this study, novel (Zr0.2(1-x)Ce0.2(1-x)Pr0.2(1-x)Y0.2(1-x)Ho0.2(1-x)Mgx)O2-δ single-phase high-entropy fluorite-structured oxides with varying Mg elemental contents were successfully synthesized at 1600 °C. Given the unique ionic radius and valence nature of Mg2+, the effects of varying the Mg doping amount on the thermophysical properties and microstructures were explored. Furthermore, the mechanism influencing high-temperature thermal conductivity was studied at the microscopic scale using first-principles calculations to clarify the nature of the thermal conductivity behavior. On one hand, an increase in oxygen vacancies leads to an enhancement of the lattice distortion degree and phonon scattering level. On the other hand, divalent Mg2+ activates the lattice via unequal substitutions, thereby reducing the thermal conductivity. The experimental and simulation results revealed that as Mg doping increases, the content of oxygen vacancies significantly increases, the degree of lattice distortion increases, phonon scattering is enhanced (19.54–21.37 THz), high-temperature thermal conductivity progressively decreases (1.91-1.20 w·m−1·K−1), and the coefficient of thermal expansion progressively increases (11.70 × 10−6-12.31 × 10−6 K−1). These results offer a novel approach for designing doped high-entropy strategies that can satisfy the performance requirements of TBCs.