Double Doping Research Articles

Thermoelectric Characteristics of Permingeatite Compounds Double-Doped with Sn and S.

Sn/S double-doped permingeatites, Cu3Sb1-xSnxSe4-ySy (0.02 ≤ x ≤ 0.08 and 0.25 ≤ y ≤ 0.50) were synthesized, and crystallographic parameters and thermoelectric characteristics were examined as a function of doping level. The lattice parameters of permingeatite were significantly modified by the dual doping of Sn and S, with S doping exerting a greater influence on lattice constants and variations in tetragonality compared to Sn doping. With an increase in the level of Sn doping and a decrease in S doping, the carrier concentration increased, leading to enhanced electrical conductivity, indicative of a degenerate semiconducting state. Conversely, an increase in S doping and a decrease in Sn doping led to a rise in the Seebeck coefficient, demonstrating p-type conductivity characteristics with positive temperature dependence. Additionally, the double doping of Sn and S substantially improved the power factor, with Cu3Sb0.98Sn0.02Se3.75S0.25 exhibiting 1.12 mWm-1K-2 at 623 K, approximately 2.3 times higher than that of undoped permingeatite. The lattice thermal conductivity decreased with increasing temperature, while the electronic thermal conductivity exhibited minimal temperature dependence. Ultimately, the dimensionless figure of merit (ZT) was improved through the double doping of Sn and S, with Cu3Sb0.98Sn0.02Se3.50S0.50 recording a ZT of 0.68 at 623 K, approximately 1.7 times higher than that of pure permingeatite.

Sulfur modified N-doped carbocatalysts promote the selectivity for H2S selective oxidation

Sulfur element is widely applied as a non-metallic dopant into carbon framework for the modulation of their chemical activities. An interesting question is whether the intrinsic catalytic performances for the H2S selective oxidation to sulfur can be manipulated by sulfur element introduction into carbocatalysts. In this study, we employ a simple solvent-free method to introduce S atoms into framework of N-doped carbocatalysts, resulting in a notable enhancement of the product S selectivity with negligible loss of H2S selective oxidation. The experimental results show that the as-synthesized N-S-C-2 catalyst exhibits a H2S conversion of 97.5 % and sulfur selectivity of >80 % at a high O2-to-H2S ratio (2.5) under continuous mode (over the dew point temperature of sulfur, c.a. 210 °C), while also demonstrating robust stability (> 100 h), anti-CO2 (up to 50 vol%) and anti-oxidation properties. Kinetic analysis and H2S/O2-TPD-MS results reveal that S introduction attenuates the adsorption and dissociation of H2S and O2 by the N-doped carbon catalyst. Furthermore, density functional theory calculations elucidate that S doping elevates the adsorption energies of H2S and O2 at the pyridinic N site, thereby moderately reducing the adsorption of H2S and O2, consequently preventing the over-oxidation of H2S to SO2 and enhancing S selectivity. The double doping promotion effect of carbon materials reported in this investigation offers an alternative insight for the development of highly selective carbon desulfurization catalysts.

A Comparative Study of Congo Red Textile Dye Photodegradation Using ZnO Al and ZnO Al+Mn Nanoparticles

Photodegradation of Congo Red textile dye was successfully carried out using ZnO Al and ZnO Al+Mn nanoparticles synthesized using the bottom-up coprecipitation method. Powder X-ray diffraction provides information that Al and Mn doping successfully inserted in the host crystal structure while maintaining the Hexagonal Wurtzite crystal structure. However, a shift in the diffraction peak caused by the lattice distance changes with the addition of doping. FE-SEM EDS provides information that both nanoparticles are nonuniform sphere-like due to the addition of dopping, and each dopping is detected through EDS spectra. There is a decrease in the gap energy in each sample. ZnO Al nanoparticles have a gap energy of 3.29 eV, and ZnO Al+Mn nanoparticles have a gap energy of 3.28 eV. However, the decrease in the gap energy is not directly related to the percentage and kinetic rate of Congo Red photodegradation. Adding 5 mg of ZnO Al Nanoparticles powder could degrade Congo Red up to 97.9 % within 120 min using UV A radiation or 0.03504/min. At the same time, adding ZnO Al+Mn Nanoparticles powder with the same parameters could only degrade 67.6 % or 0.00759/min. HIGHLIGHTS Energy Bandgap Modification of ZnO Nanoparticles The incorporation of Al single dopants and Al, Mn co-dopants into ZnO nanoparticles synthesized via a bottom-up coprecipitation method significantly alters the energy bandgap. Al single doping resulted in a bandgap of 3.29 eV, while Al, Mn double doping yielded a bandgap of 3.28 eV. Enhanced Photocatalytic Activity of Al-Doped ZnO Al-doped ZnO nanoparticles exhibited superior photocatalytic activity toward the degradation of Congo Red textile dye. With a photodegradation rate constant of 0.03504 min⁻¹, these nanoparticles achieved 97.9 % degradation of Congo Red within 120 minutes. Comparative Photocatalytic Performance of Al, Mn Co-Doped ZnO While Al, Mn co-doped ZnO nanoparticles were synthesized using the same method, their photocatalytic performance for Congo Red degradation was notably lower than that of Al-doped ZnO. The calculated photodegradation rate constant was 0.00759 min⁻¹, resulting in 67.6 % degradation within the same timeframe. GRAPHICAL ABSTRACT

Improvement of electrochemical properties of LiFe0.9Zn0.1-xMnxPO4 (x=0, 0.05, 0.075, 0.1) by double doping with Zn2+, Mn2+

Zn2+ and Mn2+ co-doped LiFe0.9Zn0.1-xMnxPO4 (where x = 0, 0.05, 0.075, 0.1) composites are synthesized by a simple one-step hydrothermal method. The composition, structure, morphology and electrochemical properties of the materials are fully characterized using XRD, SEM, TEM, EDS, CV and AC impedance tests. The results show that the co-doping of Zn2+ and Mn2+ preserves the olivine structure of LiFePO4 and also stabilizes the crystal structure, reduces the charge transfer resistance and improves the Li+ diffusion rate. When the initial specific capacity of the cathode material with the doping ratio of Zn = 0.025 and Mn = 0.075 is 161.8 mAh·g−1, the discharge specific capacity after 200 cycles is still as high as 157.8 mAh·g−1 with a capacity retention of 97.5 %, which is obviously better than the rest of the materials.

Bimetallic Sulfur-Doped Nickel-Cobalt Selenides as Efficient Bifunctional Electrocatalysts for the Complete Decomposition of Water.

The creation and enhancement of non-precious metal bifunctional catalysts with superior stability and stabilizing activity is necessary to achieve water splitting in alkaline media. The paper presents a method for preparing nickel-cobalt bimetallic selenides (NiCo-Sex/CF) using a combination of hydrothermal and high-temperature selenization techniques. NiCo-Sex/CF shows great potential as a catalyst for water separation. The catalyst's electronic structure and active centre can be modified by double doping with sulfur and selenium, resulting in increased selectivity and activity under varying reaction conditions. This method also offers the benefits of a simple preparation process and applicability to a wide range of catalytic reactions. Experimental results demonstrate that an overpotential of 194 mV produces a current density of 10 mA cm-2 when using this electrocatalyst as an OER catalyst. When used as a HER catalyst, the electrocatalyst required an overpotential of only 76 mV to generate a current density of 10 mA cm-2.Furthermore, a voltage of 1.5 V can drive the overall decomposition of water to achieve a current density of 10 mA cm-2. This study highlights the potential of sulfur-selenide double-doped catalysts for both scientific research and practical applications.

N2O Decomposition on Singly and Doubly (K and Li)-Doped Co3O4 Nanocubes─Establishing Key Factors Governing Redox Behavior of Catalysts.

The intimate mechanism of N2O decomposition on bare and redox-tuned Co3O4 nanocubes (achieved by single (Li or K) and double (Li and K) doping) was elucidated. The catalysts synthesized by the hydrothermal method were characterized by X-ray electron absorption fine structure measurements, X-ray diffraction, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, and Kelvin Probe techniques. TPSR and steady-state isothermal catalytic tests reveal that the N2O turnover frequencies are critically sensitive to the work function of the catalysts, adjusted purposely by doping. For the catalysts obtained by one-pot hydrothermal synthesis, lithiation of the Co3O4 nanocubes leads to the formation of {Li'8a, Co·16d} species, decreasing steadily the work function and the activity, while for the catalysts prepared by postsynthesis impregnation, formation of {Li'8a, Co'16d, Co··16c} species leads to a volcano-type dependence of the catalytic activity and the work function in parallel. The beneficial effect of potassium was discussed in terms of mitigation of surface potential buildup due to the accumulation of ionosorbed oxygen intermediates (surface electrostatics), which hinders the interfacial electron transfer. Analysis of the catalytic activity response to the redox tuning of Co3O4, substantiated by DFT calculations, allowed for a straightforward conceptualization of the redox nature of the N2O decomposition in terms of the lineup of frontier orbitals of the N2O/N2O- and O2-/O2 reactants with the surface DOS structure and the resultant molecular orbital interactions. The positions of the virtual bonding 3πg0(N2O)-α-3dz2 and the occupied 2πg1(O2-)-α-3dz2 states relative to the Fermi energy level play a crucial role in the regulation of the forward and backward interfacial electron transfer events, which drive the redox process.

Enhancement of thermoelectric performance by Ag/Bi/Fe co-doping into Cu3SbSe4 ceramics for green thermoelectric applications

Cu3SbSe4 is recognized for its abundant elemental availability, cost-effectiveness, and non-toxic properties, making it a promising candidate for thermoelectric applications at medium temperatures. This study explored the preparation of Bi/Fe, Ag/Fe, and Ag/Bi double-doped Cu3SbSe4 ceramics using vacuum melting and cold isostatic pressing techniques. The focus was on examining the influence of these dopants on the microstructural and thermoelectric performances of Cu3SbSe4. The analysis revealed the presence of Cu3SbSe4 and Cu2−xSe phases in the doped samples. Double doping optimized the carrier concentration, increased the effective mass, and significantly enhanced the electrical conductivity from 12.45 to 64.01 S cm−1. Notably, the power factor of the Cu2.85Ag0.15Sb0.985Bi0.015Se4 sample reached 649.1 μWm−1K−2 at 573 K. Furthermore, the thermal conductivity was significantly reduced to 0.73 W/mK. The maximum ZT value of the Cu2.85Ag0.15Sb0.985Bi0.015Se4 sample was 0.47 at 573 K. These breakthrough results demonstrate that dual doping markedly enhances the thermoelectric properties of the Cu3SbSe4 system.

Bi-doped initiates the crystal structure reconfiguration of Aurivillius, boosts piezoelectric response, and achieve PMS activation and antibiotic degradation in Bi2LaNbTiO9-BiOBr heterojunctions

Piezo-photocatalysis has been widely accepted as a research strategy for environmental treatment. However, the outstanding issues of synergistic pressure response and charge transfer are still the difficulties in this area, so it is crucial to improve these points. Doping modification of piezoelectric materials is a well-established method to enhance the piezoelectric response and promote charge transfer by modulating the crystal structure. In this study, the crystal structure of Bi4Ti3O12 has been reconstructed by double doping substitution at A and B sites, which realizes the layer change of perovskite structure and the structural distortion of MO6 (M = Ti, Nb). This change in crystal symmetry effectively enhances the piezoelectric response of the material and combined with the construction of Bi2LaNbTiO9-BiOBr (BLNT-BOB) heterojunctions, the charge distribution is dramatically improved, and the charge transfer becomes easier. Under the dual effect of heterojunction and piezo-photocatalytic coupling, the catalyst exhibited excellent catalytic performance, and the degradation rate of BhB reached 97.24 % within 20 min, After PMS activation, the degradation rate reached 98.65 % in 16 min, which was higher than that of BLNT (59.13 %) and BOB (46.81 %), and the reaction kinetics were improved by 5.3-fold and 7.4-fold. It also showed good degradation efficiency in the treatment of antibiotics, and the soybean sprout culture experiment provided a strong proof of the applicability of the catalyst in multiple pollutants and biocompatibility. This work provides valuable insights for designing piezoelectric photocatalytic structures and analyzing the activation mechanism of PMS.

Interlayered double-doped N,P-MXene/ZnIn2S4 Schottky junction composite photocatalyst: Efficient removal of ciprofloxacin and methyl orange from complex wastewater

In this study, N and P were used to double doping MXene to obtain N,P-MXene with increased layer spacing and structural defects. Schottky junction N,P-MXene/ZnIn2S4 photocatalysts with tight interfacial contacts were obtained by in situ growth of flower-like ZnIn2S4 nanosheets. The N,P-MXene interlayer spatial structure facilitates the uniform dispersion of ZnIn2S4 and the exposure of the active site. The formation of the Schottky barrier enables the two closely contacted interfaces to form a carrier transport channel, which accelerates the arrival of the charge carriers on the catalyst surface for REDOX reactions. 50 N,P-MXene/ZIS degraded 86.1 % of CIP and 93.9 % of MO. In addition, after several cycling experiments, it was proved that the photocatalyst had good structure and chemical stability. The photocatalytic mechanism was demonstrated by UPS and radical quenching experiments. N,P-MXene/ZnIn2S4 is not only suitable for pH = 7–11, but also for salt solution wastewater containing higher concentrations of NaCl or KCl. Therefore, the construction of heteroatom doped N,P-MXene/ZnIn2S4 Schottky junction photocatalysts with excellent photocatalytic degradation performance is of profound significance for the treatment of pollutants.

Anion and Cation Co-Doping of NiO for Transparent Photovoltaics and Smart Window Applications

Materials engineering based on metal oxides for manipulating the solar spectrum and producing solar energy have been under intense investigation over the last years. In this work, we present NiO thin films double doped with niobium (Nb) and nitrogen (N) as cation and anion dopants (NiO:(Nb,N)) to be used as p-type layers in all oxide transparent solar cells. The films were grown by sputtering a composite Ni-Nb target on room-temperature substrates in plasma containing 50% Ar, 25% O2, and 25% N2gases. The existence of Nb and N dopants in the NiO structure was confirmed by the Energy Dispersive X-Ray and X-Ray Photoelectron Spectroscopy techniques. The nominally undoped NiO film, which was deposited by sputtering a Ni target and used as the reference film, was oxygen-rich, single-phase cubic NiO, having a visible transmittance of less than 20%. Upon double doping with Nb and N the visible transmittance of NiO:(Nb,N) film increased to 60%, which was further improved after thermal treatment to around 85%. The respective values of the direct band gap in the undoped and double-doped films were 3.28 eV and 3.73 eV just after deposition, and 3.67 eV and 3.76 eV after thermal treatment. The changes in the properties of the films such as structural disorder, direct and indirect energy band gaps, Urbach tail states, and resistivity were correlated with the incorporation of Nb and N in their structure. The thermally treated NiO:(Nb,N) film was used to form a diode with a spin-coated two-layer, mesoporous on top of a compact, TiO2 film. The NiO:(Nb,N)/TiO2heterojunction exhibited visible transparency of around 80%, showed rectifying characteristics and the diode’s parameters were deduced using the I-V method. The diode revealed photovoltaic behavior upon illumination with UV light exhibiting a short circuit current density of 0.2 mA/cm2 and open-circuit voltage of 500 mV. Improvements of the output characteristics of the NiO:(Nb,N)/TiO2 UV-photovoltaic by proper engineering of the individual layers and device processing procedures are addressed. Transparent NiO:(Nb,N) films can be potential candidates in all-oxide ultraviolet photovoltaics for tandem solar cells, smart windows, and other optoelectronic devices.

Systematic investigation and controlled synthesis of Ag/Ti co-doped hydroxyapatite for bone tissue engineering

Hydroxyapatite (HA) is a cornerstone bio ceramic in bone tissue engineering applications, prized for its inherent biocompatibility and structural resemblance to natural bone tissue. However, both porous and dense, conventional HA formulations face notable stability and mechanical robustness constraints, impeding their broader utility. We introduce an innovative biomaterial synthesized via a straightforward and efficient sol-gel method to surmount these challenges and imbue novel scaffolds with multifunctional capabilities. Leveraging a double doping strategy, our approach seeks to enhance mechanical performance and incorporate antibacterial features, maintaining the biocompatibility of HA-based scaffolds for advanced tissue engineering applications. In pursuit of this objective, we synthesized Ag-doped, Ag, Ti-doped, and Ti-doped HA samples to explore the impact of varying dopant types and concentrations on various structural, thermal, crystallographic, chemical, morphological, mechanical, and biocompatibility characteristics. X-ray Diffraction (XRD) analysis confirmed the presence of apatitic phase compositions across all samples, while Fourier-transform Infrared Spectroscopy (FTIR) data corroborated phosphate formation and functional group identification. Scanning Electron Microscopy (SEM) studies revealed a correlation between particle size and dopant concentration, consistent with XRD findings. Nanoindentation results indicated optimal mechanical performance was achieved with balanced incorporation of Ag and Ti ions despite increased Vickers microhardness with higher Ti concentrations. All doped samples exhibited effective antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), except for the Ti-doped HA sample. Moreover, the HA sample co-doped with equal amounts of Ag and Ti demonstrated noncytotoxicity for human lung cancer (A549) cells. In contrast, all doped samples exhibited cytotoxicity towards human prostate cancer cell (PC3) cells. Statistical analysis confirmed a synergistic enhancement of biocompatibility and mechanical performance in HA samples doped with Ag and Ti ions in equal proportions. In conclusion, our study presents a simple and effective approach for enhancing HA's mechanical and antibacterial properties through co-doping with Ag and Ti. This innovative biomaterial holds significant promise for advancing bone tissue engineering applications.

Enhanced electromagnetic wave absorption of La0.8Ca0.2Fe1-xMnxO3 boosted by lattice distortion and double-exchange

Perovskite LaFeO3 with ABO3 structure is regarded as a potential candidate in electromagnetic wave absorption, considering its unique dielectric-magnetic coupling loss mechanism. However, the limited attenuation ability of pristine LaFeO3 restricts its further application. In this work, the dual doping strategy is carried out to improve the dielectric and magnetic loss capacity. Ca and Mn dual doped La0.8Ca0.2Fe1-xMnxO3 are prepared by spray pyrolysis method. The minimum reflection loss (RLmin) of La0.8Ca0.2Fe0.2Mn0.8O3 reaches −52.3 dB with an effective absorption bandwidth (EAB) of 3.92 GHz at the fitting thickness of 2.08 mm. The enhancement of the dielectric loss mainly originates from strengthened dipole polarization induced by the Jahn-Teller distortion which is caused by Ca and Mn double doping. The magnetic loss can be attributed to the improvement of double-exchange between Fe3+ –O2- -Mn3+ and Mn3+ –O2- -Mn4+ owing to the introduction of Mn. This work provides new insights into regulating the electromagnetic wave absorption performance of perovskite.

Construction of advanced Nb9VO25 electrode material by introducing graphene quantum dot for high energy supercapacitors with exceptionally high diffusive capacitance

Unreasonable tunnel structure and low intrinsic conductivity limit practical applications of niobium oxide in high-performance supercapacitors. The study reports the construction of Nb9VO25 electrode material via coordination of Nb(V) and V(V) with histidine and serine-functionalized and boron-doped graphene quantum dot (HSBGQD) and subsequent annealing. The introduction of HSBGQD and rambutan peel leads to formation of small Nb9VO25 nanocrystal and low valent Nb and V species. The combination of small size and more reasonable tunnel structure accelerates the ion diffusion. The Nb(IV) and V(IV) double doping optimizes the tunnel structure, narrows the bandgap and creates new pathways for high-speed electron transfer. The integration of defect engineering with graphene surface modification enhance the intrinsic conductivity. The Nb9VO25 electrode shows exceptionally high specific capacitance of 2925.3 F/g, which is more than 142 times that of Nb2O5. The symmetrical supercapacitor with Nb9VO25 electrodes and PVA/Li2SO4 gel electrolyte offers high specific capacitance (263 F/g at 1 A/g), high-rage capacity (138 F/g at 50 A/g), cycling stability (capacitance retention of 99.4 % after 10000-cycle), energy density (146 W h Kg−1 at 996 W Kg−1 and 77 W h Kg−1 at 50181 W kg−1) and broad application prospect in wearable electronic devices.

Coupling of modulating d-band center and optimizing interface electronic structure via MXene and Bi-metal doping in CoP achieving efficient bifunctional catalytic activity for water splitting

Bifunctional electrocatalysts that exhibit excellent catalytic activity for both hydrogen (HER) and oxygen evolution reactions (OER) are ideal for alkaline overall water splitting. The unique structure and diverse composition of cobalt phosphide catalysts are highly favorable for enhancing catalytic reaction kinetics. However, cobalt phosphide electrocatalysts typically exhibit insufficient OER activity. To overcome this text, we synthesized a Ru and V co-doped CoP-coupled highly conductive MXene catalyst with nano-arrays by in-situ growth on the surface of carbon cloth. The HER and OER overpotentials of the catalyst at 10 mA cm−2 current density were 30 and 206 mV, respectively. Furthermore, a series of physicochemical characterizations and first-principles calculations demonstrated that the increased HER and OER activities resulted from the synergistic effect established by the double doping and heterostructure. This effect produced an effective modulation of the d-band center of the catalysts, promoting adsorption effects on the intermediates. In conclusion, this work presents a novel approach to improving the electrocatalytic activity of phosphides and provides a faster and more environmentally friendly method for separating hydrogen from water.

Synergistic boost in Fe3O4 anode performance for li-ion batteries via Zn and Cu double doping and multi-walled carbon nanotube composite integration

In this study, a novel nanocomposite material comprising pure Fe3O4 (FO), doped Zn0.5Cu0.5Fe2O4-3 (ZCFO-3), and Zn0.5Cu0.5Fe2O4-3@ Multi-walled carbon nanotube (ZCFO-3@MWCNT) nanocomposite material is carefully prepared using a simple one-step hydrothermal process. Comprehensive surface and morphological analysis are conducted using X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), and High-resolution transmission electron microscopy (HRTEM), while compositional studies are investigated through Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The electrochemical performance is fully analyzed through Cyclic voltammetry (CV), Electrochemical impedance spectroscopy (EIS), rate capability tests, discharge/charge capacity, and cyclic stability evaluations. Among these three nanomaterials, ZCFO-3@MWCNT nanocomposite at 100 mA g−1 current density reveals the best performance, with a discharge capacity of 1974 mAh g–1, ZCFO-3 and FO reveal 1340 mAh g–1 and 1317 mAh g–1 respectively. After 800 cycles at 500 mA g−1 current density, ZCFO-3@MWCNT stays strong with a discharge capacity of 646 mAh g–1, while ZCFO-3 manages only 362 mAh g–1 and FO only 111 mAh g–1. After 1200 cycles at 500 mA g−1, the nanocomposite still delivers 518 mAh g–1. This study suggests that ZCFO-3@MWCNT could be a promising anode material for lithium-ion batteries.

Stabilizing the bulk phase and interface of layered oxide cathode through Li&B double doping

Layered oxide cathodes have attracted widespread attention due to their high-voltage and high discharge capacity. Nevertheless, the irreversible redox reactions of layered oxide cathode and decomposition of electrolyte at high-voltage greatly reduce the reversibility of the batteries. Herein, we employ a double-doping (Li&B) strategy to enhance the electrochemistry performance of the layered NaNi0.3Fe0.3Mn0.4O2 (NNFM) cathode at high voltage. It proved that the dissolution of the transition metal can be restricted by double doping, and the irreversible phase transition is mitigated even at high voltage. As a result, battery with the double-doping cathode exhibits excellent electrochemistry performance, which achieves a capacity of 175 mAh g−1 at 0.2C, maintaining a capacity retention of approximately 87.3% over 100 cycles at 1C, and demonstrates exceptional rate performance. This work presents a novel insight into the doping technique for the high-performance cathode materials and offers a general method for the high energy Na-ion batteries.

Enhancing performance and stability of LiNi0.8Co0.1Mn0.1O2 cathode via Na/Y dual doping for Lithium-Ion batteries

Nickel-rich layered oxide cathode materials face limitations in practical applications due to trade-offs between capacity and structural stability. As more Li+ is extracted during charging, the layered structure of nickel-rich materials becomes increasingly fragile. To address this, a double doping strategy with Na and Y is proposed in this study to enhance the strength of the layered structure. The research findings demonstrate that Na doping enlarges the spacing between Li layers in the crystal structure, while Y doping improves the reversibility of the H2-H3 phase transition but narrows the Li layer spacing in nickel-rich materials. Na and Y double doping, the advantages of Na in enlarging the Li layer, and Y in improving the H2-H3 phase transition can be harnessed simultaneously. This double doping strategy ensures that the laminar structure of the cathode material remains stable even when it is highly detached, effectively solving the trade-off between the capacity and structural stability of nickel-rich laminar cathode materials. The application in LiNi0.8Co0.1Mn0.1O2 shows that the capacity and cycle life of cathode materials can be significantly improved after Na/Y double doping. These findings open up opportunities for practical applications of nickel-rich cathode materials in lithium-ion batteries.

Impact of Nd3+, Er3+ions on the structural, morphological and opto-electrical properties of ZrO2/La2O3doped Y2O3 ceramics

In the present work, the authors have studied double doping of Rare Earth Elements (Nd3+, Er3+) into the lattice of Y2O3 ceramic in the presence of sintering additives ZrO2+La2O3 having formula (Y0.915-xZr0.02La0.06Nd0.005Erx)2O3 where x= (0.5, 1.0, 1.5 at. %). The samples are synthesized using co-precipitation method. X-ray diffraction results reveals the formation of Y2O3 structure having cubic unit cell and matched with JCPDS card No. 41-1105. A gradual shift towards higher angle side at 2θ = 29.2° has been observed with variation in Er doping. The particle size varied from 123 nm to 52 nm with doping and has a homogenous distribution. The presence of different dopants have been confirmed by XPS. The powder mixture was sintered at 1700 °C for 10hrs in an inert atmosphere, though resulting in translucent pellets when measured in the range of 200–2200 nm, due to non-uniform heating and different grain size. Under the excitation of 350 nm, the samples emitted blue, green, violet and indigo colours wavelengths, confirming transition from 4F11/2 orbitals and their band gap also decreases from 5.2 eV to 4.80 eV. The sintered samples presented a dielectric constant of 15, which goes up to 18 upon increasing the concentration of Er. These results demonstrated the correlation and the effect of double doping on Y2O3 for its opto-electronic applications.

Electronic structure regulation of nitrogen and phosphorus double doping for N, P-Co4S3/NC nanospheres to enhance all-pH hydrogen evolution

In this work, N, P-Co4S3/NC nanospheres were successfully synthesized by double ligand strategy, followed by calcination and phosphating. By adjusting the radio of methimazole and 2-methylimidazole, and changing the calcination temperature, we obtained the optimal hydrogen evolution catalyst. The doping of N and P can regulate the electronic structure of Co, and further improve the electrocatalytic hydrogen production performance. Furthermore, N from dual ligands can form nitrogen-doped carbon, thus enhancing the conductivity and stability of the catalyst. The experimental results showed that N, P-Co4S3/NC exhibited good full pH activity in 0.5 M H2SO4, 1.0 M PBS and 1.0 M KOH, and the overpotentials of 163, 185 and 168 mV were required to reach the current density of 10 mA cm−2, respectively. In this study, the dual ligands strategy can propose a new path for the design and synthesis of the catalyst precursor, and N, P codoping can effectively enhance the catalyst performance.

Achieving ultrahigh piezoactuation constant of 2240 pm/V and giant electrostrain of 1.12% simultaneously in BNT-based polycrystalline ceramics

Ultrahigh electrostrain (Sm) at low driving field in lead-free piezoceramics could alleviate key concerns by reducing energy consumption and the risk of electrical breakdown for advanced applications. However, the giant electrostrain always accompanied with an extremely large drive field is a long-standing conflict referred as the strain-electric field trade-off. Herein, we engineer a novel strategy of introducing the B-site unequal double doping cations (ZnSn0.5)4+ into (Bi0.5Na0.5)0.93Ba0.07TiO3 ceramic to generate the spontaneous phase transition from relaxor state to ferroelectric state, polar nanoregions PNRs and defect cluster. The giant strain of Sm= 1.12% is achieved by integrating the field-induced phase transition, morphotropic phase boundary MPB and the enhanced synergistic effect between the spontaneous polarization Ps and the defect cluster polarization Pd under a low electric field of 50 kV/cm, thus yielding extremely large piezoactuation constant d33 * =2240 pm/V in (Bi0.5Na0.5)0.93Ba0.07Ti0.97(ZnSn0.5)0.03O3 piezoceramics. This finding also demonstrates an unexpected new route to design novel ferroelectric materials via nonconventional mechanisms.