Science China-Materials
·
2023
·Vol. 66
·期 8
·3213-3222
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IF 8.1
Wen Zihao,Meng Hong,Jiang Shengda,Tang Zhongyu,Liu Yiwen,Chu Yanhui
Developing superior oxidation resistance of high-entropy diborides is critical for extending their potential applications in harsh environments. Herein, we developed non-equimolar (Hf,Zr,Ta,W)B 2 high-entropy diborides with superior oxidation resistance by adjusting W contents for the first time. The as-fabricated (Hf 0.28 Zr 0.28 Ta 0.28 W 0.15 )B 2 samples are predicted to possess superior oxidation resistance at 1473–1773 K through the oxidation depth quantitative analysis obtained by machine learning, which is attributed to the reason that the moderate WO 3 can effectively inhibit the volatilization of B 2 O 3 . Furthermore, a four-layered structure is found in the generated product layers at 1773 K, which is due to the preferential oxidation of Hf and Zr elements at low oxygen partial pressure and the different diffusion activation energies of oxide products. The preferential oxidation of Hf and Zr elements is further demonstrated by the computational phase stability diagrams, and oxygen adsorption energies and charge transfer between oxygen atoms and different metal adsorption sites via first-principles calculations. Such superior performance endows (Hf 0.28 Zr 0.28 Ta 0.28 W 0.15 )B 2 with potential applications as ultrahigh-temperature structural materials.
研究领域:
材料科学
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高温材料
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计算材料科学
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产品关联
DOI
高影响因子
Journal of Materials Chemistry C
·
2023
·Vol. 11
·期 31
·10694-10702
·
IF 6.4
Yiwen Zhu,Yifan Yang,Yongqi Zhu,Yifan Chen,Zhenyu Liu,Fengmeng Lei,Hua Yu,Qinan Mao,Jiasong Zhong,Jing Wang
Near-infrared (NIR) phosphor-converted light-emitting diodes (pc-LEDs) have been attracting considerable attention as a new solid-state light source for night vision technology and biological imaging applications. Nevertheless, the requirement for toxic and concentrated HF in the previous synthesis of fluoride phosphors may cause environmental pollution and safety problems. Here, we report a feasible HF-free green synthesis method using a two-step process to prepare the Cr3+ source and a series of Cr3+, Li+ doped NIR phosphors using aqueous solution and methanol solution. X-ray diffraction analysis indicates that the pure target material was successfully synthesized. The luminescence intensity of K2ZnF4:Cr3+,Li+ is 2.58 times improved compared with K2ZnF4:Cr3+. Furthermore, the prepared phosphors show broadband emission in the range of 650 to 1000 nm, with a full width at half-maximum (FWHM) of 139 nm peaking at 783 nm. The NIR output power of the pc-LED fabricated with the K2ZnF4:Cr3+,Li+ phosphor and a 450 nm blue chip reaches 1007 mW at 320 mA. This work provides a promising phosphor for application as a NIR light emitting diode and has important implications for the green synthesis of HF-free Cr3+-doped fluorides in the future.
研究领域:
材料科学
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光电
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化学
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环境科学
✓ 已验证
DOI
高影响因子
OPTICAL MATERIALS
·
2023
·
IF 3.9
Siyue Wang,Xiaoman Teng,Chao Liu,Hanfei Zhu,Hongbu Cheng,Jing Yan,Li Wang,Zhenyan Liang,Jun Ouyang
Due to a synergistic effect of piezo-catalysis and photocatalysis , piezo-photocatalysis is gaining popularity as an effective approach to remove organic pollutants. In this work, single-component piezo-photocatalytic nanoparticles of UiO-66-NH 2 (Hf) metal-organic frameworks were prepared by a hydrothermal process with an average diameter of ∼52.6 nm. An ultrafast piezo-photocatalysis degradation of RhB solution was achieved by using the UiO-66-NH 2 (Hf) nanoparticles . Under UV light and ultrasound irradiation, the percentage of dye degradation for an initial RhB concentration of 5 mg/L reached 91 % in 60 s. The removal mechanism of RhB was investigated via capture experiments of active species, which revealed that the hydroxyl radicals and hole play a key role in the degradation of RhB. This work provides a reference for the piezo-photocatalytic capability and the underlying mechanism of single-component metal-organic framework based nanomaterials , promoting their further development in technological applications involving highly efficient catalysts.
研究领域:
环境科学
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材料科学
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催化
✓ 已验证
产品关联
DOI
高影响因子
Materials Research Express
·
2023
·Vol. 10
·期 11
·116202
·
IF 2.3
Yifan Yang,Yongqi Zhu,Shuang Wu,Xinyue Li,Qinan Mao,Yifan Chen,Jiasong Zhong,Yiwen Zhu
In this study, a series of near-infrared (NIR) KZnF3:Cr3+ phosphors was prepared by different chromium sources using a HF-free hydrothermal method. The influence of different chromium sources on the crystal structure, morphology, and luminescence properties of Cr3+-doped KZnF3 phosphors were systematically investigated. The results showed that the chromium source changed from CrF3·xH2O to (NH4)3CrF6 and leaded to an increased crystal field, resulting in a blue shift of the emission peak position from 803 nm to 753 nm, accompanied by the full-width half maximum (FWHM) reduced from 140 nm to 122 nm. Moreover, KZnF3:0.03Cr3+ (CrF3·xH2O) and KZnF3:0.03Cr3+ ((NH4)3CrF6) phosphors maintained 58% and 87% of their initial room-temperature intensity at 423 K, respectively. These results indicated that altering the synthetic raw materials provided new insights for designing NIR phosphors with highly thermal stability.
研究领域:
材料科学
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光学材料
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荧光粉技术
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发光材料
✓ 已验证
DOI
高影响因子
Journal of Advanced Ceramics
·
2022
·Vol. 11
·期 11
·1801-1814
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IF 11.534
Cheng Fuhao,Zhang Fengnian,Liu Yufeng,Guo Meng,Cheng Chufei,Hou Jiadong,Miao Yang,Gao Feng,Wang Xiaomin
Environmental barrier coatings (EBCs) with excellent chemical resistance and good high-temperature stability are of great significance for their applications in next-generation turbine engines. In this work, a new type of high-entropy fluorite-structured oxide (Ce 0.2 Hf 0.2 Y 0.2 Pr 0.2 Gd 0.2 )O 2− δ (HEFO-1) with different Ti 4+ contents were successfully synthesized. Minor addition of Ti 4+ could be dissolved into a high-entropy lattice to maintain the structure stable, effectively reducing the phase formation temperature and promoting the shrinkage of bulk samples. Heat treatment experiments showed that all the samples remained a single phase after annealing at 1200–1600 °C for 6 h. In addition, high-entropy (Ce 0.2 Hf 0.2 Y 0.2 Pr 0.2 Gd 0.2 Ti 0.2 x )O 2− δ demonstrated great resistance to calcium—magnesium—alumina—silicate (CMAS) thermochemical corrosion. When the content of Ti was increased to x = 0.5, the average thickness of the reaction layer was about 10.5 after being corroded at 1300 °C for 10 h. This study reveals that high-entropy (Ce 0.2 Hf 0.2 Y 0.2 Pr 0.2 Gd 0.2 Ti 0.2 x )O 2− δ is expected to be a candidate for the next-generation EBC materials with graceful resistance to CMAS corrosion.
研究领域:
材料科学
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涂层
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高温材料
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腐蚀抗性
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Guihua Xu,Qiaoning He,Kexin Huang,Ying Wang,Chun Pu,Ganggang Chang,Xiaoyu Yang
Benefiting from their unique properties including faster mass transfer, more exposed active sites and large molecule recognition, hierarchically porous metal–organic frameworks (HP-MOFs), in the form of ultrasmall nanoparticles (NPs) and having self-assembled interparticle mesopores, have garnered greater attention in recent years that given to typical MOFs. However, controllable synthesis of HP-MOFs on the nanoscale remains a significant challenge. Herein, for the first time, a facile top-down acid etching strategy was developed to fabricate a series of nanosized (∼15 nm) mesoporous MOF, HP-UiO-66-NH 2 (Hf). The sizes of mesopores in this material can be effectively tuned by simply controlling the concentration of propionic acid (PA) utilized in the preparation solution. Interestingly, the generated mesoporous HP-UiO-66-NH 2 (Hf) has excellent stability and can be readily constructed by using PA etching solution that has been recycled at least four times. Remarkably, HP-UiO-66-NH 2 (Hf) displays a high size-selectivity for adsorption of enzymes. Associated with its highly matched mesopore size, the nanocomposite generated by complexation with glucose oxidase (GOD), [email protected] 2 (Hf) has a higher catalytic activity and a significantly enhanced stability (recycled at least 7 times) in promoting oxidation of glucose compared to its MOF counterpart, [email protected] 2 (Hf) and native GOD .
研究领域:
材料科学
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化学工程
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纳米技术
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催化
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生物催化
✓ 已验证
产品关联
DOI
高影响因子
BIOMASS & BIOENERGY
·
2025
·
IF 5.8
Zonghui Liu,Xueting Zhu,Chao Cai,Jiayi Zheng,Bing Yan,Liangmin Ning,Dan Yang,Bing Xue
Developing conversion routes from lignocellulosic platform compounds to high-value chemicals is fundamental to advancing sustainable resource utilization in the bioeconomy. In this study, we designed a series of SBA-15-supported bifunctional catalysts with precisely tunable Lewis acid sites (LAS), Brønsted acid sites (BAS), and basic sites through strategic incorporation of hafnium species and heteropolyacids (HPAs), demonstrating their exceptional performance in the multi-step tandem conversion of furfural (FUR) to γ-valerolactone (GVL). HfO 2 was used LAS and basic sites to catalyze the transfer hydrogenation reaction of FUR and levulinate ester using 2-propanol as the H-donor. Complementary to this, HPA could catalyze the hydrolytic ring-opening of furans. The amount of LAS, BAS, and basic sites was adjusted by changing the ratio of HPA to HfO 2 and the types of HPA (phosphotungstic acid (HPW), phosphomolybdic acid (HPMo), silicotungstic acid (HSiW) and silicomolybdic acid (HSiMo)). The ratio of HPA to HfO 2 and types of HPA have a great influence on the catalytic performance, among which HPW/Hf-SBA-15_0.37 (W/Hf = 0.37) was identified as the best catalyst and presented the highest GVL selectivity (73.5 %) under optimized reaction conditions. The poison experiment (addition of benzoic acid, pyridine, or 2,6-lutidine to the reaction) indicated that both acidic and basic sites play important role in the FUR to GVL reaction. Moreover, by correlating the catalyst performance with the BAS/LAS ratio of catalysts, it can be found that the balance between the BAS and LAS is also the key to higher GVL selectivity.
研究领域:
催化
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绿色化学
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生物经济
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材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2023
·
IF 5.7
Yuzhu Shen,Wei Sun,Yonglong Xu,Qingbo Wen,Hongbo Zhang,Xiang Xiong
In this study, to overcome the difficulties associated with the preparation of PyC-ceramic interface and controllable deposition of the structure, we initially used a two-step molten salt infiltration method to prepare a C/C-Me-Zr-Hf (Me = Ta, Si) composite with excellent oxyacetylene ablation performance. The microstructure and the behavior of ablative were addressed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) as well as by X-ray diffraction（XRD）. The results reveals that C/C-ZrHfC-SiC composite prepared by two-step molten salt infiltration method have a controllable ultra-high temperature ceramic structure and better ablation resistance.
研究领域:
材料科学
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航空航天工程
✓ 已验证
DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2020
·
IF 8.247
Wenlian Wang,Tianxiang Yang,Shuai Li,Jing Lu,Xiaoyang Zhao,Weizhen Fan,Chaojun Fan,Xiaoxi Zuo,Shaolong Tie,Junmin Nan
Lithium-ion batteries (LIBs) with high-nickel ternary material cathode can provide a high specific capacity but are more sensitive to the H 2 O/HF contents and functional additives in the electrolyte. In this work, 1,4-phenylene diisocyanate (PPDI) is developed as an H 2 O/HF scavenger and film-forming electrolyte additive to enhance the performances of pouch LiNi 0 · 6 Co 0 · 2 Mn 0 · 2 O 2 (NCM622)/graphite batteries. Compared with batteries containing the blank electrolyte, the electrochemical performances of batteries with the PPDI-containing electrolyte can be significantly improved. Thereinto, after 600 cycles at room temperature (25 °C) and 300 cycles at high temperature (45 °C), the capacity retentions for the batteries with the PPDI-containing electrolyte are 84.9% and 81.3% at 1C, while the rates for the batteries with the blank electrolyte are only 29.3% and 14.4%, respectively. With the aid of theory calculations and spectroscopic characterization, the reasons behind the performance enhancement are elucidated, and the reaction mechanism of PPDI and H 2 O/HF is proposed. It is demonstrated that PPDI can scavenge H 2 O/HF in the electrolyte and form stable and highly conductive films on two electrodes to stabilize NCM622 and improve battery performances. Besides the functionalized electrolyte, this work can also inspire new ideas to develop functionalized electrolytes for high-performance NCM622-based LIBs.
研究领域:
材料科学
·
电化学
·
能源存储
·
电池技术
✓ 已验证
产品关联
DOI
高影响因子
COMPOSITES PART B-ENGINEERING
·
2025
·
IF 14.2
Tongle Xu,Jing Yang,Kangshuai Zhu,Kaidong Zhang,Qinmin Pan
Poly (1,3-dioxolane)-based (PDOL-based) solid polymer electrolytes have attracted much attention in solid-state lithium metal batteries (LMBs) due to their high ionic conductivity and excellent lithium anode compatibility. However, practical application of PDOL-based electrolytes is hindered by poor thermal stability and irreversible degradation caused by hydrofluoric acid (HF) at high temperatures. Herein, we introduce a multifunctional cross-linking agent glycerol triglycidyl ether (TASG) to improve the ionic conductivity and thermal stability of the electrolyte. The stable three-dimensional network structure of PDOL-TASG enhances the thermal stability of the electrolyte. The epoxy group in TASG effectively captures the HF generated by the electrolyte at high temperatures, preventing irreversible degradation of PDOL chains. This capture elevates the thermal stability of the PDOL-based electrolyte from 70 °C to 120 °C. LMBs employing PDOL-TASG electrolyte demonstrate an initial specific discharge capacity of 169 mAh g −1 with 96.4 % capacity retention after 120 cycles at 90 °C at 1C rate. Even at 100 °C, the Li|PDOL-TASG|LFP batteries demonstrate exceptional cyclability, surpassing most reported batteries using solid polymer electrolytes. This work elucidates the mechanism of HF-induced PDOL degradation and provides a strategy to increase high-temperature durability of LMBs using solid polymer electrolytes.
研究领域:
材料科学
·
电化学
·
储能技术
·
高分子化学
·
锂离子电池
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2023
·
IF 6.2
Shiyi Zhang,Mengdi Cheng,Yangxi Yan,Zhimin Li,Pangpang Wang,Ri-ichi Murakami,Dongyan Zhang
High-performance piezoelectric materials , whose displacement is sensitive to an external field and vice versa, are constantly required in electromechanical applications. Here, we introduce Nd 3+ ions into 0.49Pb(Nb 2/3 Ni 1/3 )O 3 -0.51Pb(Hf 0.3 Ti 0.7 )O 3 (PNN-PHT) ceramics via the solid-state method. By constructing a ferroelectric system in the morphotropic phase boundary region and exploiting the synergistic effect of polar nanoregions and an enhanced local structural heterogeneity, excellent piezoelectricity and dielectric properties are obtained. The optimized piezoelectric coefficient d 33 , dielectric constant ε 33 , electromechanical coupling factor k p , and dielectric loss tanδ are 1125 pC/N, 8667, 0.66 %, and 1.94 %, respectively. The Vogel-Fulcher law and relaxation analysis were adopted to understand the origin of the high piezoelectricity. The Rayleigh analysis method was used to study the intrinsic and extrinsic contributions to the piezoelectricity of the Nd-doped PNN-PHT ceramics, the extrinsic contribution was found to be up to 19 % in the optimal region (PNN-PHT + 0.4 at. % Nd 2 O 3 ). Moreover, according to in-situ ferroelectric measurements and fatigue measurements, the PNN-PHT + 0.4 at. % Nd 2 O 3 ceramic exhibits excellent fatigue resistance and stable piezoelectric behavior at 60 ℃ . This work provides an approach to realize high-performance piezoelectric ceramics with good electromechanical stability under external condition, which is expected to expand the range of application of piezoelectric materials, e.g., for transducers.
研究领域:
材料科学
·
电陶瓷
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压电材料
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铁电材料
✓ 已验证
DOI
高影响因子
Materials
·
2023
·Vol. 16
·期 12
·4426
·
IF 3.4
Guang Zeng,Ping Xu,Chen Zeng,Qizhong Huang,Zhean Su
HfCxN1−xnanoparticles were synthesized using the urea-glass route, employing hafnium chloride, urea, and methanol as raw materials. The synthesis process, polymer-to-ceramic conversion, microstructure, and phase evolution of HfCxN1−x/C nanoparticles were thoroughly investigated across a wide range of molar ratios between the nitrogen source and the hafnium source. Upon annealing at 1600 °C, all precursors demonstrated remarkable translatability to HfCxN1−xceramics. Under high nitrogen source ratios, the precursor exhibited complete transformation into HfCxN1−xnanoparticles at 1200 °C, with no observed presence of oxidation phases. In comparison to HfO2, the carbothermal reaction of HfN with C significantly reduced the preparation temperature required for HfC. By increasing the urea content in the precursor, the carbon content of the pyrolyzed products increased, leading to a substantial decrease in the electrical conductivity of HfCxN1−x/C nanoparticle powders. Notably, as the urea content in the precursor increased, a significant decrease in average electrical conductivity values was observed for the R4-1600, R8-1600, R12-1600, and R16-1600 nanoparticles measured at a pressure of 18 MPa, yielding values of 225.5, 59.1, 44.8, and 46.0 S·cm−1, respectively.Keywords:HfCxN1−x;pyrolysis;ultra-high-temperature ceramics;nanoparticles
研究领域:
材料科学
·
无机化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）