Small
·
2024
·Vol. 20
·期 31
·2309034
·
IF 13
Sheng Wu,Binli Xiao,Dongliang Jiang,Yao Xiao,Peishan Shao,Zhiyao Zhou,Yinzhen Wang,Puxian Xiong
Mechanoluminescence (ML) materials are featured with the characteristic of “force to light” in response to external stimuli, which have made great progress in artificial intelligence and optical sensing. However, how to effectively enable ML in the material is a daunting challenge. Here, a Lu 3 Al 2 Ga 3 O 12 :Cr 3+ (LAGO: Cr 3+ ) near infrared (NIR) ML material peaked at 706 nm is reported, which successfully realizes the key to unlock ML by the lattice-engineering strategy Ga 3+ substitution for Al 3+ to “grow” oxygen vacancy (O v ) defects. Combined with thermoluminescence measurements, the observed ML is due to the formation of defect levels and the ML intensity is proportional to it. It is confirmed by X-ray photoelectron spectroscopy and electron paramagnetic resonance that such a process is dominated by O v , which plays a crucial role in turning on ML in this compound. In addition, potential ML emissions from 4 T 2 and 2 E level transitions are discussed from both experimental and theoretical aspects. This study reveals the mechanism of the change in ML behavior after cation substitution, and it may have important implications for the practical application of O v defect-regulated turn-on of ML.
研究领域:
材料科学
·
凝聚态物理
·
光学功能材料
·
缺陷化学
·
传感技术
✓ 已验证
DOI
高影响因子
CATALYSIS TODAY
·
2018
·
IF 4.667
Dawang Chu,Chen Zhao
The effective and selective conversion of cellulose to valuable fuels and chemicals is highly attractive. In this paper, we prepared a catalyst with the adjacent surface Cu° and oxygen-deficient WO x (2 < x < 3) species by reduction of CuWO 4 precursor, and such catalyst coupled with Ni/activated carbon (AC) attained high yield (71 wt%) and good cycling performances in catalyzing one-step hydrothermal conversion of cellulose to ethylene glycol (EG), highly superior to the performances on physically mixed Ni/C, Cu/C and WO 3 . The increased Cu doping amounts led to a higher ratio of the lower valence state W (V or IV) to the high valence W(VI) as indicated by XPS, XRD, and TPR-H 2 analyses. The oxygen vacancies on the hydrogen-reduced CuWO 4 sample dramatically increased, probably due to the benefits from the substantial dissociated H• on the neighboring Cu° center. The EG yields from cellulose are shown to be proportional to the concentrations of oxygen vacancies on WO x , which catalyzes the important elementary retro-aldol step reaction via adsorbing C 6 sugar intermediates in a specific way. It is inferred that Cu introduction is mainly used to create more oxygen vacancies on the WO x surface that helps adsorbing oxygenates, while Ni fast hydrogenates of hydroxyacetaldehyde to EG and avoids coking, constructing a multi-functional synergistic catalytic process from converting of cellulose to EG in the high-temperature water
研究领域:
催化化学
·
生物质转化
·
绿色化学
·
材料化学
·
能源化学
✓ 已验证
DOI
高影响因子
MATERIALS LETTERS
·
2015
·
IF 2.489
Jingzhong Zhao,Weiqiang Xing,Yang Li,Kathy Lu
Oxygen-deficient anatase TiO 2 sheets with dominant (001) facets are becoming a hot research topic due to their promising high activity in heterogeneous reactions . In this work, a series of (001) facets dominated TiO 2 with distributed oxygen vacancies and Ti 3+ was prepared by a simple hydrothermal method with the TiB 2 as a precursor. The as-prepared powders were characterized by X-ray diffraction (XRD), Scanning electron microscope (SEM), Transmission Electron Microscope (TEM), X-ray photoelectron spectroscopy (XPS) and UV–visible diffuse reflectance spectroscopy (UV–vis). The results show that the particle size of as-prepared TiO 2 increases and its band gap narrows with the hydrothermal temperature increasing from 140 °C to 180 °C. Besides, oxygen vacancies and Ti 3+ are generated during the TiB 2 hydrolysis, which leads to new absorption spectrum in the visible light region. Photocatalytic test shows that sample prepared at 180 °C presents the highest degradation efficiency.
研究领域:
材料科学
·
光催化
·
纳米材料
·
表面化学
·
半导体材料
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2018
·Vol. 29
·期 16
·13925-13930
·
IF 2.324
Li Tianjing,Shi Qingle
In this paper, explain a new relationships between Bi 3+ content, the phase crystal, microstructure and conductivity for Sm and Bi co-doped Ce 0.8− x Sm 0.2 Bi x O 1.9−1/2 x ( x = 0, 0.05, 0.1, 0.15, 0.2) electrolytes prepared by co-precipitation method. The XRD patterns showed that this compounds exhibit a fluorite-type cubic structure after the samples calcined at 700 °C for 4 h and the cell volumes of increased when the Bi content increased. In addition, for the samples sintered at 1400 °C for 4 h, the Bi doping improves the relative density, the grain size and the average thermal expansion coefficient (TEC). More in details, the relative density and TEC increase with the Bi content. Form the AC impedance spectroscopy measurements, the conductivity of the sintered samples is found to improve with the increasing of Bi content (for x ≤ 0.15), which is ascribed to the increasing of the number of oxygen ion vacancies and the increase in the unit cell volume. However, the conductivity decreases when the Bi content is further increased (0.15 < x ≤ 0.2), which is ascribed the reduction of the number of free oxygen vacancies. The highest conductivity at 800 °C is 5.6 × 10 −2 S/cm and the activation energy is 0.83 eV for Ce 0.65 Sm 0.2 Bi 0.15 O 1.825 , indicating that this would be a promising electrolyte for the intermediate temperature-solid oxide fuel cell applications.
研究领域:
材料科学
·
无机非金属材料
·
固态离子学
·
能源材料
·
燃料电池
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2017
·
IF 9.446
Hui He,Xueting Lin,Shujun Li,Zeng Wu,Jingheng Gao,Junliang Wu,William Wen,Daiqi Ye,Mingli Fu
Surface species and oxygen vacancies were studied in MnO x (0.4)-CeO 2 toward repeated soot oxidation. MnO x (0.4)-CeO 2 catalysts prepared by the citric acid complex method were repeatedly used in a 10% O 2 /Ar gas flow and showed favorable activity and satisfactory durability toward soot oxidation. X-ray diffraction (XRD), N 2 adsorption/desorption, Electron paramagnetic resonance (EPR), X-ray photoelectron spectroscopy (XPS) and in situ visible/UV Raman characterization methods were utilized to investigate the structural features of fresh and reused catalysts. The irreversible conversion of high valence manganese species as well as the reduction of Frenkel-type oxygen vacancies and lattice oxygen could be clearly observed in the reused samples, which were associated with the slight deactivation. Spectators and participators were two existing forms of Frenkel-type oxygen vacancies. It was noteworthy that the participators almost fully regenerated after each reaction cycle, which ensured the ability to activate O latt in repeated soot oxidation process. Therefore, the catalysts maintained favorable activity and satisfactory durability, which was mainly because the relatively stable level of participators.
研究领域:
催化化学
·
环境催化
·
材料化学
·
表面科学
·
能源化学
✓ 已验证
DOI
高影响因子
POWDER TECHNOLOGY
·
2024
·
IF 4.5
Huifeng Xu,Pengfei Wang,Saiwei Luan,Lixia Cheng,Zhenxiao Fu,Xiuhua Cao,Lei Zhang,Shuhui Yu,Rong Sun
Conventionally, tetragonality in BaTiO 3 powder is attributed to grain size, disregarding the role of Ba/Ti ratio. However, our study reveals a significant impact of Ba/Ti ratio on tetragonality in BaTiO 3 . With an increase in Ba/Ti ratio from 0.990 to 1.010, particle size remains around 200 nm. Tetragonality initially rises from 1.006 to a maximum of 1.0092 at Ba/Ti = 1.000, then decreases to 1.005. Lower tetragonality is associated with Ba or Ti vacancies, using density functional theory (DFT), we analyzed the electron density and lattice distinction in BaTiO 3 powders. Both Ba and Ti vacancies affect lattice distortion, the Ti vacancies leading to more significant lattice expansion and lower tetragonality than Ba vacancies. Using this powder, we fabricated high-density BaTiO 3 ceramics and multi-layer ceramics capacitors (MLCCs) with X7R temperature stability (−55 to 125 °C, ±15% coefficient) and excellent reliability. This strategy has broad implications for tetragonal BaTiO 3 nanopowders and MLCCs development.
研究领域:
材料科学
·
无机非金属材料
·
电子陶瓷
·
固态化学
·
功能材料
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·Vol. 48
·期 13
·18876-18883
·
IF 5.532
Zhixin Ma,Yang Qi,Jun Wang,Xiaoguo Bi,Xu-dong Liu,Xiaodong Li,Ji-guang Li,Xudong Sun
SrTiO 3 is a promising thermoelectric material for applications in harsh environments, owing to its excellent thermoelectric (TE) properties and high-temperature stability. The effect of annealing in carbon powders on the TE properties of SrTiO 3−δ in the [111] direction was experimentally investigated and analysed using first-principles calculation. The electrical conductivity of the SrTiO 3−δ single crystals in the [111] direction increases with an increase in annealing temperature in the range of 1573–1673 K, which is opposite to that in the [510] direction as shown in a previous experiment. This is attributed to the different variation trend of carrier concentration. First-principle calculation results show that the carrier concentration in the [111] direction increases with increasing oxygen vacancy concentration, but it is the opposite in the [510] direction. Strong anisotropy of carrier concentration should be caused by the difference in atomic arrangement, making difference in the amount of free electrons that maybe constrained at high oxygen vacancy in different directions. Although the SrTiO 3−δ single crystal annealed at 1573 K shows a lower electrical conductivity, it obtains higher power factor with the maximum value of 2.24 mW m −1 K −2 at 323 K, which is predominantly due to its higher effective mass. It also yields the highest ZT value of 0.18 at 873 K owing to the lower thermal conductivity . The results of this study are imperative for the design and development of perovskite TE materials.
研究领域:
材料科学
·
凝聚态物理
·
热电材料
·
晶体学
·
固体化学
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2023
·
IF 6.2
Ao Li,Binfang He,Guangchao Jin,Dongmei Liu,Jingbo Chen
Li-rich manganese-based cathode material is expected to be extremely promising for next-generation lithium-ion batteries due to its high specific capacity derived from additional anion redox behavior and low cost of the main element manganese. However, the irreversible release of lattice oxygen results in poor structural stability and inferior electrochemical performances , such as low initial Coulomb efficiency, irreversible capacity decay and serious voltage decay, which limits its commercialization. Herein, a simple strategy to improve the structural stability and electrochemical performances by one-step treatment with triethylamine (TEA) at moderate temperature is reported. TEA was used as a surface treatment reagent to prepare the modified Li-rich manganese-based cathode materials with oxygen vacancies and local structural distortion on the surface. The presence of surface distortion layer and oxygen vacancies inhibits irreversible oxygen release. The result exhibits that initial Coulomb efficiency, rate performance and initial discharge specific capacities are improved. After 100 cycles at a current density of 1 C, the specific capacity of the surface-treated material is 204.3 mAh g -1 (172.6 mAh g -1 for the pristine material), with a capacity retention of 81.26%. Even at a high current density of 10 C, the discharge specific capacity of 139.4 mAh g -1 is still achieved, demonstrating the excellent electrochemical performance. This study provides a simple and effective strategy for constructing special surface structures on Li-rich manganese-based materials to achieve high performance.
研究领域:
材料科学
·
电化学
·
能源存储
·
锂离子电池
·
固态化学
✓ 已验证
DOI
高影响因子
Small
·
2024
·Vol. 20
·期 26
·2310387
·
IF 13
Wei Luo,Yanli Yu,Yucheng Wu,Wenbin Wang,Yimin Jiang,Wei Shen,Rongxing He,Wei Su,Ming Li
Rational design of heterostructure catalysts through phase engineering strategy plays a critical role in heightening the electrocatalytic performance of catalysts. Herein, a novel amorphous/crystalline (a/c) heterostructure (a-CoS/Ni 3 S 2 ) is manufactured by a facile hydrothermal sulfurization method. Strikingly, the interface coupling between amorphous phase (a-CoS) and crystalline phase (Ni 3 S 2 ) in a-CoS/Ni 3 S 2 is much stronger than that between crystalline phase (c-CoS) and crystalline phase (Ni 3 S 2 ) in crystalline/crystalline (c/c) heterostructure (c-CoS/Ni 3 S 2 ) as control sample, which makes the meta-stable amorphous structure more stable. Meanwhile, a-CoS/Ni 3 S 2 has more S vacancies (S v ) than c-CoS/Ni 3 S 2 because of the presence of an amorphous phase. Eventually, for the oxygen evolution reaction (OER), the a-CoS/Ni 3 S 2 exhibits a significantly lower overpotential of 192 mV at 10 mA cm −2 compared to the c-CoS/Ni 3 S 2 (242 mV). An exceptionally low cell voltage of 1.51 V is required to achieve a current density of 50 mA cm −2 for overall water splitting in the assembled cell (a-CoS/Ni 3 S 2 || Pt/C). Theoretical calculations reveal that more charges transfer from a-CoS to Ni 3 S 2 in a-CoS/Ni 3 S 2 than in c-CoS/Ni 3 S 2 , which promotes the enhancement of OER activity. This work will bring into play a fabrication strategy of a/c catalysts and the understanding of the catalytic mechanism of a/c heterostructures.
研究领域:
材料科学
·
电化学
·
催化化学
·
纳米材料
·
能源材料
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2021
·Vol. 32
·期 11
·14274-14285
·
IF 2.478
Gao Qianqian,Dai Yuqiang,Wei Xile,Zhou Changping,Gong Wenfeng,Song Haixiang,Guo Zhanhu,Li Chengbo
The Aurivillius compound Pb x Bi 6− x Fe 0.5 Co 0.5 Ti 4 O 18 thin films were prepared via chemical solution deposition method and the influence of Pb 2+ ions doping on the structure, ferroelectric and leakage properties were studied. With the increasing concentration of Pb 2+ ions, the lattice distortion is increased and the growth of the films along ab plane is promoted. The calculation results show that the internal stress of the films increases with the increase of Pb 2+ concentration. For the samples with low Pb 2+ doping concentration ( x < 0.6), the leakage current densities are also decreased, which can be attributed to the decrease in oxygen vacancy concentration. Due to the enhanced lattice distortion and decreased leakage current densities, the ferroelectric properties are improved. The film with x = 0.2 has a high saturation polarization of 42.3 µC/cm 2 . According to the fitting results, the leakage conduction mechanism is attributed to the combined effect of space-charge-limited conduction mechanism and ionic conduction mechanisms.
研究领域:
材料科学
·
凝聚态物理
·
功能材料
·
铁电学
·
薄膜制备
✓ 已验证
DOI
高影响因子
FUEL
·
2023
·
IF 7.4
Muhammad Yousaf,Yuzheng Lu,Majid Niaz Akhtar,Ali Sarosh Khawaja,Khalid Mujasam Batoo,Sajjad Hussain,Asma Noor,Muhammad Akbar,Hu Enyi,M.A.K Yousaf Shah,Naveed Mushtaq,Bin Zhu
Lattice defects in rare earth (RE) doped single-phase semiconductor materials play a key role in structural modifications and physicochemical characteristics, resulting to enhance the ionic conductivity. In this work, we synthesized lanthanum doped samarium oxide with different mole ratios and applied it as a ceramics membrane fuel cell device to enable high peak power density (PPD) at low operational temperatures (520–400 °C). The samples are capable of triple charge H + /O 2− /e − conduction and enhance the catalytic function of the cell in terms of HOR and ORR kinetics by producing lattice defects. The fabricated Sm 1.5 La 1.5 Fe 5 O 12 (2-SLFO) fuel cell device exhibits a high OCV of 1.13 V with a maximum PPD of 864.26 mW/cm 2 at 520 °C. Durability measurement verifies that 2-SLFO-based fuel cell device can be worked for 60 h under fuel cell conditions (H 2 /air) at 520 °C. The first principle calculations using density functional theory (DFT) demonstrate that the higher oxygen vacancy concentration in the 2-SLFO sample may cause to the higher charge-transfer kinetics, subsequent in the enhancement of ions transportation of the fabricated fuel cell device.
研究领域:
材料科学
·
电化学
·
能源材料
·
固态离子学
·
燃料电池技术
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2016
·
IF 5.31
Shunhang Wei,Rong Wu,Xiaoxiang Xu,Jikang Jian,Haixia Wang,Yanfei Sun
Black core-shelled anatase titania were successfully prepared using a simple one-step synthetic method by calcining colloid titania precursor in N 2 flow under atmospheric pressure. The physicochemical properties of the as-prepared samples were characterized by various techniques such as X-ray diffraction, high resolution transmission electron microcopy, etc. The samples demonstrate a unique core-shelled structure and electron paramagnetic resonance spectra reveal the presence of high concentration of Ti 3+ and oxygen vacancies at the surface, which accounts for their black appearance. A possible mechanism for the formation of such core–shell structure is proposed based on the results (X-ray photoelectron spectra, etc) of products prepared under different ration between urea and hydrochloric acid. Ethanol absolute is found to have critical effect in preventing phase transition of titania (from anatase to rutile) upon elevated temperatures. The black appearance of the sample powder (high visible light absorption) as well as slow electron/hole recombination rate after introducing oxygen vacancies/N species signify the core-shelled anatase titania as an efficient visible light active photocatalyst.
研究领域:
材料科学
·
光催化
·
纳米材料
·
表面化学
·
无机合成
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）