CRYSTAL GROWTH & DESIGN
·
2019
·
IF 4.153
Ziqing Li,Pengfei Zhu,Jimin Ding,Nianjing Ji,Yang Chen,Zhenyan Wang,Xiulan Duan,Huaidong Jiang
Yb-doped inorganic crystals have attracted great attention in both basic and applied research, and the quest for suitable crystal hosts and understanding the corresponding crystal field environments are still worth studying in laser application. In this context, inclusion-free RbTiOPO4:Ta:Yb (RTP:Ta:Yb) single crystals with dimensions up to 3 × 30 × 15 mm3 were grown by top-seeded solution growth method under optimized growth conditions. The good crystalline quality of the as-grown RTP:Ta:Yb crystals were confirmed by X-ray diffraction rocking curve. The chemical compositions of the crystals were determined through electron probe microanalysis (EPMA). The results showed that the Ta distribution coefficient is 0.90–1.28, and the Yb distribution coefficient is 0.13–0.37. Double doping of Ta5+ ions can effectively increase the concentration of Yb3+ ions in the RTP crystal, and the concentration of Yb3+ ion in RTP crystal can reach 1.26 × 1020 atom/cm3. The influence of Ta and Yb dopants on the electronic structures of RTP crystals was studied using high-resolution X-ray photoelectron spectroscopy (XPS), and the chemical strengths of Ti–O and P–O bonds are related to the binding energy difference. RTP:Ta:Yb crystals exhibit excellent transparent performance in the wavelength range of 0.35–4.5 μm, and the transmittance is about 83%. Photoluminescence spectra show five emission peaks of Yb3+ in crystals, and the main emission peak is located at 972 nm. Two different coordination sites for Yb3+ were observed, and their energy levels were determined in the crystal field of the RTP:Ta structure. Furthermore, the crystal field strengths of Yb3+ in different host crystals associated with their distorted coordination environments were evaluated and discussed in detail. The results demonstrate that the RTP:Ta:Yb single crystal endowed with high crystal field strength and good luminescence property is suitable for laser application.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2023
·Vol. 13
·期 8
·5208-5218
·
IF 3.9
Thi Viet Ha Luu,Ngoc Nhiem Dao,Hoang Ai Le Pham,Quang Bac Nguyen,Van Cuong Nguyen,Phuc Huu Dang
In this work, Ta-doped ZnO (Ta-ZnO) nanomaterials were synthesized by the hydrothermal method at different temperatures (110, 150, and 170 °C) for the photodegradation of methylene blue (MB) under visible light. Ta doping significantly affects the crystal defects, optical properties, and MB photocatalytic efficiency of ZnO materials. The optical absorption edge of Ta-ZnO 150 was redshifted compared to undoped ZnO, correlating to bandgap narrowing (EgTa–ZnO = 2.92 eV; EgZnO = 3.07 eV), implying that Ta doped ZnO is capable of absorbing visible light. Besides, Ta-doping was the reason for enhanced blue light emission in the photoluminescence spectrum, which is related to the oxygen defect V0O. It is also observed in the XPS spectra, where the percentage of oxygen in the oxygen-deficient regions (O531.5 eV) of Ta-ZnO150 is higher than that of ZnO150. It is an important factor in enhancing ZnO's photocatalytic efficiency. The MB degradation efficiency of Ta-doped ZnO reached the highest for Ta-ZnO 150 and was 2.5 times higher than ZnO under a halogen lamp (HL). Notably, the influence of hydrothermal temperature on the structural, morphological, and photoelectrochemical properties was discussed in detail. As a result, the optimal hydrothermal temperature for synthesizing the nanorod is 150 °C. Furthermore, photocatalytic experiments were also performed under simulated sunlight and natural sunlight. The nature of the photo-oxidative degradation of MB was also investigated.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SOLID STATE SCIENCES
·
2024
·
IF 3.4
Renzhong Xue,Liuyang Zhao,Xiaosong Liu,Haiyan Wang,Xiang Zhu,Yifan Xiao,Chunyu Yuan,Binbin Cao,Ziyang Chen,Tao Li,Haiyang Dai
In this paper, Ta-doped Bi 2/3 Cu 3 Ti 4 O 12 (BCTO) ceramics are prepared by solid-state method. Phase structure, microstructure, optical, dielectric, and non-Ohmic properties of all samples are systematically investigated. Cu/Ta-rich phases at grain boundaries (GB) together with defects affect the microstructure, causing grain size and compactness to increase first and then decrease. Moreover, Ta doping increases the optical band gap of BCTO from 4.03 to 4.25 eV as well as the GB activation energy and GB barrier. An increase in dielectric constant (Ɛ r ), nonlinear coefficient (α) and breakdown field (E b ), and a decrease in the dielectric loss (tanδ) are observed in Ta-doped BCTO ceramics. The improvement in dielectric and non-Ohmic properties can be attributed to the internal barrier layer caused by GB Schottky barrier structure. In particular, Bi 2/3 Cu 3 Ti 3.95 Ta 0.05 O 12 ceramic exhibits the high Ɛ r of ∼45997 and the low tanδ of ∼0.035 at 10 kHz along with α of ∼5.62, and E b of ∼3.45 kV/cm. The temperature-independent (-110-210 °C) dielectric response confirms that temperature stability of specimens increases with doping. These results suggest that improved optical, dielectric, and non-Ohmic properties in Bi 2/3 Cu 3 Ti 4 O 12 can be achieved simultaneously via defect engineering.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2021
·
IF 5.816
Na Ye,Zhao Jiang,Tao Fang
The low-palladium Pd/TaN–C catalyst is synthesized by a surfactant-free solvothermal approach and exhibits high activity (2613.18 mA mg Pd −1 ), durability and CO tolerance for MOR (methanol oxidation reaction) in alkaline media , 12.4 folds that of the commercial Pd/C. XPS and electrochemical results indicate that the interfacial Pd–TaNO bond is generated. This also brings the enhancement of OH ad adsorption responsible for anti-CO poisoning ability. Density Functional Theory (DFT) calculations indicate that the reaction pathway and the rate-determining step are changed for methanol decomposition to CO on the Pd 4 /TaN(001) surface compared with Pd (111). The preferred pathway can be described as: CH 3 OH→CH 3 O→CH 2 O→CHO→CO. Furthermore, the results indicate that the adsorption of OH is enhanced and the energy barrier of COOH formation from CO + OH is reduced with the high concentration of hydroxyl on the Pd 4 /TaN(001) surface, further confirming the bi-functional effect of hydroxyl on the CO tolerance.
研究领域:
电化学
·
催化材料
·
理论计算
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2017
·Vol. 7
·期 84
·53111-53116
·
IF 3.108
Ziqing Li,Yang Chen,Pengfei Zhu,Nianjing Ji,Xiulan Duan,Huaidong Jiang
RTP crystals doped with four different Ta concentrations were grown by high-temperature solution method. Ta dopants changed the growth habit of RTP and the (100) faces were more developed than the other crystal faces. The chemical composition and electronic structure were analyzed using Electron Probe Microanalysis (EPMA) and X-ray photoelectron spectroscopy (XPS). Ta elements could easily incorporate into RTP crystals from the melt due to the large distribution coefficient. As Ta content increased, the Rb 3d, Ti 2p, P 2p, O 1s XPS spectra showed a shift towards higher binding energy. The relative Ta atomic concentration in RTP:Ta crystals was calculated and it was determined that the molar ratio between Ta and Ti was higher than the nominal ratio. The thermal properties and SHG efficiency were also studied. Ta dopants decreased the transition temperature from the orthorhombic RTP phase to the cubic RTP phase and increased the decomposition temperature of the cubic RTP phase. When the Ta concentration increased to 9 mol%, the specific heat of the doped crystal was 1.5 times that of pure RTP crystal at 300 °C and SHG intensity was improved by 59% when compared with pure RTP. The results show that Ta doping is helpful for improvement of SHG efficiency and increasing resistance to laser irradiation.
研究领域:
材料科学
·
晶体学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
Materials Research Express
·
2020
·Vol. 7
·期 2
·025518
·
IF 1.929
Jiali Xue,Kuibao Zhang,Daimeng Chen,Jianjun Zeng,Baozhu Luo
Ta-doped Li7La3Zr2O12 (Ta-LLZO) solid electrolyte ceramics were synthesized by solid-state sintering, spark plasma sintering (SPS) and SPS plus heat-treatment (two-step method) using LiOH·H2O, La2O3, ZrO2 and Ta2O5 as the raw materials. The Ta-LLZO samples prepared from these three routes are all in cubic phase structure. However, the solid-state method results in Ta-LLZO samples with different particle sizes and porous morphology, while the samples prepared by SPS route contain fewer internal voids and smaller particle size. The two-step method not only retains the high compactness of SPS samples, but also the increment of grain size. The SEM results demonstrate that Ta-LLZO sintered by the two-step method shows optimal electrical properties. And the total ionic conductivity is 4.6 × 10−3 S cm−1 at 150 °C and the activation energy is calculated to be 0.38 eV.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2020
·Vol. 46
·期 8
·10917-10924
·
IF 3.83
Li Yang,Qiushi Dai,Lei Liu,Dingsheng Shao,Kaili Luo,Sidra Jamil,Hong Liu,Zhigao Luo,Baobao Chang,Xianyou Wang
Solid electrolytes could address the increasingly urgent safety and energy density concerns of lithium-ion batteries. Among several kinds of solid electrolytes, Ta-doped Li 7 La 3 Zr 2 O 12 (Ta-LLZO) became a research hotspot because of its high Li-ion conductivity and chemical stability against Li-metal and air. However, the preparation of high quality LLZO ceramic electrolyte via conventional air ambient sintering method is still a big challenge due to the serious “Li-loss” and abnormal grain growth phenomenon during the long-time high-temperature sintering process . Herein, a new rapid ultra-high-temperature air ambient sintering method without mother powder (MP) is put forward for the preparation of high quality Ta-LLZO ceramic electrolyte. The rapid sintering strategy can effectively restrain “Li-loss”. Furthermore, it is demonstrated that the none-mother-powder method is superior to traditional mother-powder method. Ta-LLZO ceramics sintered without MP via this rapid sintering method own small grain size, tight grain boundary, dense microstructure and high conductivity. Specifically, the Ta-LLZO ceramic sintered at 1360 °C for 10 min without MP exhibits high conductivity (8.5 × 10 −4 S cm −1 at 25 °C) and high relative density (97%), which equate those made by hot pressing sintering method. Without MP, the sintering process can avoid a lot of material waste and simplify the operation process. Moreover, the rapid sintering process can sharply shorten sintering time and reduce energy consumption. Therefore, this low-cost high-efficient sintering strategy can be effectively used in the large-scale production of high-quality Ta-LLZO ceramic electrolyte.
研究领域:
材料科学
·
固态离子学
·
能源材料
·
电化学
·
无机非金属材料
·
电池技术
✓ 已验证
DOI
高影响因子
International Journal of Minerals Metallurgy and Materials
·
2024
·Vol. 31
·期 9
·2102-2109
·
IF 5.6
Jiang Shanshan,Qiu Hao,Xu Shaohua,Xu Xiaomin,Jiang Jingjing,Xiao Beibei,Julião Paulo Sérgio Barros,Su Chao,Chen Daifen,Zhou Wei
To explore highly active and thermomechanical stable air electrodes for intermediate-temperature solid oxide fuel cells (IT-SOFCs), 10mol% Ta 5+ doped in the B site of strontium ferrite perovskite oxide (SrTa 0.1 Fe 0.9 O 3− δ , STF) is investigated and optimized. The effects of Ta 5+ doping on structure, transition metal reduction, oxygen nonstoichiometry, thermal expansion, and electrical performance are evaluated systematically. Via 10mol% Ta 5+ doping, the thermal expansion coefficient (TEC) decreased from 34.1 × 10 −6 (SrFeO 3− δ ) to 14.6 × 10 −6 K −1 (STF), which is near the TEC of electrolyte (13.3 × 10 −6 K −1 for Sm 0.2 Ce 0.8 O 1.9 , SDC), indicates excellent thermomechanical compatibility. At 550–750°C, STF shows superior oxygen vacancy concentrations (0.262 to 0.331), which is critical in the oxygen-reduction reaction (ORR). Oxygen temperature-programmed desorption (O 2 -TPD) indicated the thermal reduction onset temperature of iron ion is around 420°C, which matched well with the inflection points on the thermos-gravimetric analysis and electrical conductivity curves. At 600°C, the STF electrode shows area-specific resistance (ASR) of 0.152 Ω·cm 2 and peak power density (PPD) of 749 mW·cm −2 . ORR activity of STF was further improved by introducing 30wt% Sm 0.2 Ce 0.8 O 1.9 (SDC) powder, STF + SDC composite cathode achieving outstanding ASR value of 0.115 Ω·cm 2 at 600°C, even comparable with benchmark cobalt-containing cathode, Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3− δ (BSCF). Distribution of relaxation time (DRT) analysis revealed that the oxygen surface exchange and bulk diffusion were improved by forming a composite cathode. At 650°C, STF + SDC composite cathode achieving an outstanding PPD of 1117 mW·cm −2 . The excellent results suggest that STF and STF + SDC are promising air electrodes for IT-SOFCs.
研究领域:
材料科学
·
能源化学
·
电化学
·
无机非金属材料
·
热力学与动力学分析
✓ 已验证
DOI
高影响因子
ChemistrySelect
·
2024
·Vol. 9
·期 28
·e202304550
·
IF 1.9
Zishuang Guo,Zeyi Wang,Haiwang Wang,Changxiang Xie,Xiao Xiang,Chengang Zhang,Jian Qi
Graphical A sol-gel assisted solid-phase method was employed to prepare BaTiO 3 doped with varying Ta 5+ doping amounts. The results showed that Ta 5+ doped into the BaTiO 3 lattice and caused lattice distortion when the heat treatment temperature reached 1052.7 °C. The 1.25 mol %Ta 5+ -doped BaTiO 3 exhibited the best activity of photocatalytic water splitting for hydrogen production, which was 2.4 times that of BaTiO 3 . BaTiO 3 , as a perovskite type material with excellent chemical stability and suitable conduction, has been widely studied in the field of photocatalysis. However, it can only absorb ultraviolet light because of its wide band gap. Herein, the lifetime of photogenerated electrons of BaTiO 3 doped with Ta 5+ can be enhanced. To study the band structure and photocatalytic performance of Ta-doped BaTiO 3 , sol-gel assisted solid-phase method was employed to prepare BaTiO 3 doped with varying Ta 5+ doping amounts, and the structure characteristic and formation mechanism of the Ta-doped BaTiO 3 were analyzed. The results showed that the heat treatment temperature reached 1052.7 °C, sufficient thermodynamic conditions were obtained for Ta 5+ to dope into the BaTiO 3 lattice, and lattice distortion occurred in BaTiO 3 . Meanwhile, the particle size after doping decreased with the increase of Ta 5+ doping amount. The 1.25 mol %Ta 5+ -doped BaTiO 3 had the lowest band gap (3.077 eV), and the photocatalytic water splitting had the best hydrogen evolution activity, which was 2.4 times that of BaTiO 3 . Furthermore, the conductance potential of 1.25 mol %Ta 5+ -doped BaTiO 3 was more negative than that of BaTiO 3 , which improved the thermodynamic advantage of the photocatalytic water splitting, and it had higher and more stable photoresponse and photogenerated carrier migration rate.
研究领域:
材料科学
·
光催化
·
可再生能源
✓ 已验证
产品关联
DOI
高影响因子
Journal of Advanced Ceramics
·
2022
·Vol. 11
·期 10
·1530-1541
·
IF 11.534
Zhang Chang,Hu Xiangchen,Nie Zhiwei,Wu Cong,Zheng Nan,Chen Shaojie,Yang Yihang,Wei Ran,Yu Jiameng,Yang Nan,Yu Yi,Liu Wei
Garnet-type oxide is one of the most promising solid-state electrolytes (SSEs) for solid-state lithium-metal batteries (SSLMBs). However, the Li dendrite formation in garnet oxides obstructs the further development of the SSLMBs seriously. Here, we report a high-performance garnet oxide by using AlN as a sintering additive and Li as an anode interface layer. AlN with high thermal conductivity can promote the sintering activity of the garnet oxides, resulting in larger particle size and higher relative density. Moreover, Li 3 N with high ionic conductivity formed at grain boundaries and interface can also improve Li-ion transport kinetics. As a result, the garnet oxide electrolytes with AlN show enhanced thermal conductivity, improved ionic conductivity, reduced electronic conductivity, and increased critical current density (CCD), compared with the counterpart using Al 2 O 3 sintering aid. In addition, Li symmetric cells and Li∣LiFePO 4 (Li∣LFP) half cells using the garnet electrolyte with the AlN additive exhibit good electrochemical performances. This work provides a simple and effective strategy for high-performance SSEs.
研究领域:
材料科学
·
电化学
·
能量存储
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry A
·
2020
·Vol. 8
·期 39
·20666-20676
·
IF 11.301
Die Su,Li Liu,Zhixiao Liu,Jing Dai,Jiaxing Wen,Min Yang,Sidra Jamil,Huiqiu Deng,Guozhong Cao,Xianyou Wang
Ta-doped TiO2/C nanofibers are synthesized by an electrospinning method. First-principles calculations reveal that the Ta dopant can lower the Li/K diffusion barrier, which is beneficial for improving the rate capability. According to the electronic structure analysis, the dopant can obviously shift the conduction band of TiO2 downward, resulting in significantly improved electronic conductivity. Ta doping causes phase transformation from anatase to rutile, and increases the specific surface area. The well-designed rutile Ta-doped TiO2/C nanofibers show outstanding electrochemical properties in both Li-metal half cells and K-metal half cells, which are much better than those of pristine anatase TiO2/C nanofibers. At 2 A g−1, 5% rutile Ta-doped TiO2/C nanofibers could deliver high reversible specific capacities of 399 mA h g−1 in Li-ion batteries after 1000 cycles whereas deliver 148 mA h g−1 in K-ion batteries after 800 cycles. When assembled, the full cells with 5% rutile Ta-doped TiO2/C nanofibers as the anode and commercial LiFePO4/perylene-3,4,9,10-tetracarboxylic dianhydride as the cathode show excellent cycling performance and can light up more than 18 LEDs. These results demonstrate that Ta-doped TiO2/C nanofibers are a promising anode material for Li/K ion batteries.
研究领域:
材料科学
·
电化学
·
纳米技术
·
能源存储
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）