Nature Communications
·
2019
·Vol. 10
·期 1
·1-12
·
IF 11.878
Cao Na,Chen Zheng,Zang Ketao,Xu Jie,Zhong Jun,Luo Jun,Xu Xin,Zheng Gengfeng
The electrochemical N 2 fixation to produce ammonia is attractive but significantly challenging with low yield and poor selectivity. Herein, we first used density function theory calculations to reveal adjacent bi-Ti 3+ pairs formed on anatase TiO 2 as the most active electrocatalytic centers for efficient N 2 lying-down chemisorption and activation. Then, by doping of anatase TiO 2 with Zr 4+ that has similar d -electron configuration and oxide structure but relatively larger ionic size, the adjacent bi-Ti 3+ sites were induced and enriched via a strained effect, which in turn enhanced the formation of oxygen vacancies. The Zr 4+ -doped anatase TiO 2 exhibited excellent electrocatalytic N 2 fixation performances, with an ammonia production rate (8.90 µg·h −1 ·cm −2 ) and a Faradaic efficiency of 17.3% at −0.45 V versus reversible hydrogen electrode under ambient aqueous conditions. Moreover, our work suggests a viewpoint to understand and apply the same-valance dopants in heterogeneous catalysis, which is generally useful but still poorly understood.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Xingyu Chen,Yeqing Guan,Zhaolin Zhong,Fenglin Wang,Wei Li,Haijun Mao,Zhuofeng Liu,Weijun Zhang
The effect of Zr 4+ substitution for Ti 4+ on the phase evolution and microwave dielectric properties of (Cu 1/3 Nb 2/3 ) 0.25 Ti 0.75- x Zr x O 2 (0 = x ≤ 0.35) ceramics prepared via conventional solid-state method has been investigated. With the increase of Zr substitution, the ceramics exhibit a gradual phase transition from a tetragonal rutile phase to an orthorhombic srilankite phase, where the synthesis of the srilankite phase at atmospheric pressure and temperature below 1200 °C in this study is reported for the first time. The crystal structure is tetragonal rutile type for the unsubstituted composition, orthorhombic srilankite type for the compositions with x > 0.30, and the compositions in between is a two-phase region with a mixture of rutile and srilankite. The Zr substitution has a great influence on the microstructure of the ceramics. In particular, for compositions where x > 0.1, the grain boundaries are surrounded by elongated powdery particles. The microwave dielectric properties of the ceramics are closely related to the phase transition process, in which Q × f is significantly improved and τ f decreases almost linearly with the increase of the content of srilankite phase. Optimum microwave dielectric properties with a permittivity of 35.1, a Q × f value of 7270 GHz, and a near-zero τ f of 9.0 ppm/°C are obtained in the ceramics with x = 0.3 sintered at 1150 °C for 4 h, which provides a new option for microwave devices requiring medium-permittivity dielectric ceramics .
研究领域:
材料科学
·
电子材料
✓ 已验证
产品关联
DOI
高影响因子
Materials Research Express
·
2023
·Vol. 10
·期 8
·086201
·
IF 2.3
Bing Liu,Jingheng Liang,Lili Wang,Zian Cheak Tiu
β-NaYF4: Yb3+/Tm3+/Zr4+ microcrystals are synthesized by a facile hydrothermal route. The up-conversion (UC) luminescence and photoelectric effects are enhanced simultaneously with the introduction of Zr4+ ions under IR excitation. With the Tm3+ ions fluorescence spectra under 980 nm excitation, the blue and red emissions reached the highest intensity in the case of 4 mol% Zr4+ doping. Taking the advantage of Zr4+ stimulates the free electrons transfer from the valence band (VB) to the conduction band (CB) in β-NaYF4:Yb3+/Tm3+/Zr4+ microcrystals, the photocurrent reached the highest intensity in the case of 4 mol% Zr4+ doping at 780 nm excitation. The β-NaYF4: Yb3+/Tm3+/Zr4+ microcrystals with both enhanced UC luminescence and photoelectric properties are highly potential to contribute in photovoltaic and infrared sensors application.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2024
·
IF 5.8
Hezhen Wu,Huidong Tang,Qing Hu,Yanqiao Xu,Wentao Li,Xiaojun Zhang,Feng Jiang,Guo Feng,LianJun Wang,Wan Jiang
Recently, vacancy-ordered double perovskite phosphors have garnered significant attention due to their high quantum efficiency, elevated carrier mobility, and favorable fluorescence properties. Vacancy ordered double perovskite phosphors has poor fluorescence properties due to the high number of vacancies. The fluorescence characteristics and stability can be enhanced through strategic ion doping. This study synthesized Zr 4+ ion-doped Cs 2 SnCl 6 : 5 %Te using hydrochloric acid-assisted precipitation method. The inclusion of Zr 4+ ions in proper proportions facilitated Jahn-Teller structural distortion in Te 4+ , thereby enhancing the generation of bright yellow-green emission. The photoluminescence quantum yield (PLQY) achieved a peak of 70.9 % at a Zr 4+ ion doping level of 15 %. Furthermore, a water stability test was conducted on the phosphors. At 15 % doping with Zr ions, The Cs 2 Zr 0.15 Sn 0.8 Cl 6 : 5 %Te phosphors demonstrated a remarkable stability, which maintained 100 % of its initial fluorescence intensity after immersion in water for 14 h, proving the excellent stability of the phosphors against water exposure. A white light-emitting diode (WLED) with color coordinates of (0.3486, 0.364), a correlated color temperature of 4915 K, and a color-rendering index (Ra) of 86 was prepared using Cs 2 Zr 0.15 Sn 0.8 Cl 6 : 5 %Te phosphor. This development offers a novel and eco-friendly approach to solid state lighting.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2023
·
IF 9.5
Zhiqiang Yang,Enyue Zhao,Na Li,Lei Gao,Lunhua He,Baotian Wang,Fangwei Wang,Yusheng Zhao,Jinkui Zhao,Songbai Han
Increasing the charging cutoff voltage is a viable approach to push the energy density limits of LiCoO2 and meet the requirements of the rapid development of 3C electronics. However, an irreversible oxygen redox is readily triggered by the high charging voltage, which severely restricts practical applications of high-voltage LiCoO2. In this study, we propose a modification strategy via suppressing surface ligand-to-metal charge transfer to inhibit the oxygen redox-induced structure instability. A d0 electronic structure Zr4+ is selected as the charge transfer insulator and successfully doped into the surface lattice of LiCoO2. Using a combination of theoretical calculations, ex situ X-ray absorption spectra, and in situ differential electrochemical mass spectrometry analysis, our results show that the modified LiCoO2 exhibits suppressed oxygen redox activity and stable redox electrochemistry. As a result, it demonstrates a robust long-cycle lattice structure with a practically eliminated voltage decay (0.17 mV/cycle) and an excellent capacity retention of 89.4% after 100 cycles at 4.6 V. More broadly, this work provides a new perspective on suppressing the oxygen redox activity through modulating surface ligand-to-metal charge transfer for achieving a stable high-voltage ion storage structure.
研究领域:
材料科学
·
电化学
·
储能技术
✓ 已验证
DOI
PubMed
高影响因子
Frontiers in Chemistry
·
2020
·
IF 3.693
Li Yingying,Liu Chunyan,Zhang Peisen,Huang Jiayi,Ning Haoran,Xiao Peng,Hou Yi,Jing Lihong,Gao Mingyuan
The rare-earth nanocrystals containing Er3+ emitters offer very promising tools for imaging applications, as they can not only exhibit up-conversion luminescence but also down-conversion luminescence in the second near-infrared window (NIR II). Doping non-lanthanide cations into host matrix was demonstrated to be an effective measure for improving the luminescence efficiency of Er3+ ions, while still awaiting in-depth investigations on the effects of dopants especially those with high valence states on the optical properties of lanthanide nanocrystals. To address this issue, tetravalent Zr4+ doped hexagonal NaGdF4:Yb,Er nanocrystals were prepared, and the enhancement effects of the Zr4+ doping level on both up-conversion luminescence in the visible window and down-conversion luminescence in NIR II window were investigated, with steady-state and transient luminescence spectroscopies. The key role of the local crystal field distortions around Er3+ emitters was elucidated in combination with the results based on both of Zr4+ and its lower valence counterparts, e.g., Sc3+, Mg2+, Mn2+. Univalent ions such as Li+ was utilized to substitute Na+ ion rather than Gd3+, and the synergistic effects of Zr4+ and Li+ ions by co-doping them into NaGdF4:Yb,Er nanocrystals were investigated toward optimal enhancement. Upon optimization, the up-conversion emission of co-doped NaGdF4:Yb,Er nanocrystals was enhanced by more than one order of magnitude compared with undoped nanocrystals. The current studies thus demonstrate that the local crystal field surrounding emitters is an effective parameter for manipulating the luminescence of lanthanide emitters.
研究领域:
材料科学
·
光学
·
生物医学成像
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Applied Energy Materials
·
2025
·
IF 5.5
Yin Zhu,Jiupai Ni,Chengsheng Ni
Cu doping in ferrite perovskites was reported to enhance the low-temperature performance for the oxygen reduction reaction (ORR) of a protonic solid oxide fuel cell (H-SOFC). Zr4+ as a donor for doping in rare-earth-element-free BaFe0.9–xCu0.1ZrxO3−δ (x = 0, 0.05, and 0.1) was studied to achieve a trade-off between the high-performance electrocatalysis and stability of the Cu-containing perovskite. Zr4+ stabilized the cubic structure of the perovskite and inhibited the formation of hexagonal BaFeO3 by decreasing the Goldschmidt tolerance factor of the perovskite. Compared with BaFe0.9Cu0.1O3−δ (Zr0), BaFe0.85Cu0.1Zr0.05O3−δ (Zr5) and BaFe0.8Cu0.1Zr0.1O3−δ (Zr10) exhibit higher electric conductivity and surface exchange kinetics but a lower thermal expansion coefficient. At 600 °C, the cell with Zr10 exhibits a peak power of 547.73 mW cm–2, a polarization resistance of 0.03 Ω cm2, and a chronoamperometry of 673.13 mA cm–2 at 0.6 V after 140 h. Therefore, Zr4+ doping in the ferrite cathode can improve the ORR kinetics and durability of low-temperature H-SOFCs.
研究领域:
材料科学
·
能源科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
OPTICS LETTERS
·
2024
·Vol. 49
·期 8
·1896-1899
·
IF 3.1
Jinxing Zhao,Zhongwei Man,Zhongwei Man,Shuaibing Wang,Chaoqi Hao,Zhenzhen Yu,Xu Li,Xu Li,Aiwei Tang
Next-generation display and lighting based on quantum dot light-emitting diodes (QLEDs) require a balanced electron injection of electron transport layers (ETLs). However, classical ZnO nanoparticles (NPs) as ETLs face inherent defects such as excessive electron injection and positive aging effects, urgently requiring the development of new types of ETL materials. Here, we show that high stability SnO2 NPs as ETL can significantly improve the QLED performance to 100567 cd·m−2 luminance, 14.3% maximum external quantum efficiency, and 13.1 cd·A−1 maximum current efficiency using traditional device structures after optimizing the film thickness and annealing the temperature. Furthermore, experimental tests reveal that by doping Zr4+ ions, the size of SnO2 NPs will reduce, dispersion will improve, and energy level will shift up. As expected, when using Zr-SnO2 NPs as the ETL, the maximum external quantum efficiency can reach 16.6%, which is close to the state-of-the-art QLEDs based on ZnO ETL. This work opens the door for developing novel, to the best of our knowledge, type ETLs for QLEDs.
研究领域:
材料科学
·
光电显示技术
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）