JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
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2019
·
IF 4.029
Yang Lyu,Hui Tang,Guangdong Zhao
Polymer-derived ceramics (PDCs), such as silicon oxycarbide and its derivatives, show an exceptional high oxidative stability under extreme conditions. A novel multicomponent silicon oxycarbide system tailoring with transition metal (hafnium) and boron is fabricated by sol-gel and solvothermal method. Amorphous SiHBOC was formed via the condensation of Si–OH, B–OH and Hf–OH groups, respectively, and the bonds of Si–O–Hf and Si–O–B– were detected by FTIR and XPS characterization. After high-temperature pyrolysis, the precursor is converted to a rigid ceramic material that has an 85.8 wt % ceramic yield of SiHfBOC. We investigate the oxidation resistance performance of SiHfBOC using the isothermal oxidation test at 1400 °C. The results showed that the oxidative stability of SiHfBOC was significantly superior to than those of SiBOC ceramic.
研究领域:
材料科学
·
化学工程
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高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2026
·
IF 19.7
Yaning Gong,Dingyu Qiu,Xingchen He,Junhui Shao,Najun Li,Dongyun Chen,Hua Li,Qingfeng Xu,Jianmei Lu
Hybrid HfO 2 -PMA subnanobelts are synthesized by cluster–nuclei co-assembly. • Subnanometer belt morphology enhances piezoelectric polarization response. • Hf-O-Mo interfacial orbital coupling enhances charge separation. • PMA redox pairs act as electron buffers for efficient CO 2 activation. • Dilute CO 2 is efficiently converted into syngas via piezocatalysis. Efficient piezocatalytic conversion of dilute CO 2 into syngas offers a sustainable route for industrial flue gas valorization, yet conventional piezoelectric materials are often constrained by lattice rigidity and rapid charge recombination under weak mechanical stress. Herein, we constructed ultrathin 1D HfO 2 -phosphomolybdic acid (PMA) hybrid subnanobelts (SNBs) via cluster-nuclei co-assembly. The subnanometer architecture and flexible morphology induce an intense polarization response by leveraging the piezoelectric size effect, enabling HfO 2 -PMA SNBs to achieve remarkable CO and H 2 production rates of 4.5 and 5.8 mmol g −1 h −1 , respectively. In-situ FTIR spectra and density functional theory (DFT) calculations reveal that the asymmetric Hf-O-Mo interfacial coordination induces spontaneous electron transfer from HfO 2 to PMA, constructing a robust built-in electric field. Concurrently, the reversible redox properties of PMA clusters further enrich interfacial electron density and facilitate CO 2 adsorption and activation through Hf-O-Mo coupling, lowering the formation energy barrier of the key *COOH intermediates. This interfacial electronic structure engineering strategy establishes a novel paradigm for mechanical-energy-driven CO 2 conversion and offers a new approach for designing emerging sub-nanometer piezocatalysts. Download: Download high-res image (202KB) Download: Download full-size image
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JOURNAL OF ALLOYS AND COMPOUNDS
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2026
·
IF 6.7
Bei-Chen Gao,Yu Tian,Run-Ping Liu,Yi-Xin Wang,Yang You,Wei-Ming Guo,Hua-Tay Lin
A two-step method including low-temperature pretreatment and high-temperature homogenization was developed to prepare high-purity (Ti 0.2 V 0.2 Ta 0.2 Nb 0.2 Hf 0.2 )(C 0.75 N 0.25 ) powder. In the first step, the reaction mixture was heated to 1450 ℃ to form intermediate carbonitride phases through carbothermal reduction-nitridation, and the second step at 1700 ℃ produced a single-phase high-entropy carbonitride. The powder prepared by single-step treatment at 1750 ℃ contained 2.28 wt% nitrogen and 0.18 wt% oxygen. In contrast, the two-step powder exhibited higher nitrogen content (2.45 wt%) and lower oxygen content (0.09 wt%), and the formation of a complete single-phase solid solution enabled accurate calculation of its composition (Ti 0.2 V 0.2 Ta 0.2 Nb 0.2 Hf 0.2 )(C 0.78 N 0.21 O 0.01 ). The ceramic prepared from the two-step powder achieved 99.8% relative density, with an average grain size of 4.58 ± 0.32 μm, a Vickers hardness of 22.73 ± 0.51 GPa, and a fracture toughness of 3.16 ± 0.30 MPa·m 1/2 , whereas the single-step ceramic reached only 86.5% relative density.
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ACS Applied Materials & Interfaces
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2020
·
IF 8.758
Jingcheng Du,Li Chen,Xinjuan Zeng,Shuai Yu,Wei Zhou,Luxi Tan,Lichun Dong,Cailong Zhou,Jiang Cheng
UiO-66 metal–organic frameworks (MOFs) are unstable in some harsh aqueous environments, which limit their practical applications. We demonstrate a postsynthetic modification methodology to transform hydrophilic Zr(Hf)-UiO-66 into superhydrophobic Zr(Hf)-UiO-66-SH-y (SH = thiol, y = fluoroalkyl) by introducing long fluoroalkyl chains into organic linkers through a thiol–ene click reaction. Water contact angles of the four modified UiO-66 MOFs are all larger than 150°. The grafted low-surface-energy fluorine-containing groups become an effective protective shield for the MOFs, making them exhibit remarkable stability in extreme conditions such as alkaline (pH = 12), saturated HCl, and high concentration of NaCl solution (20 wt %). The Zr-UiO-66 MOFs grafted with 1H,1H,2H-perfluoro-1-hexene have high CO2 adsorption contents of 1.54 and 2.88 mmol·g–1 at 298 and 273 K, respectively. Moreover, the superhydrophobic MOFs also showed potential application in oil/water separation.
研究领域:
材料科学
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化学工程
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PubMed
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
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2023
·
IF 5.7
Yulan Yu,Guanghui Feng,Yujun Jia,Hejun Li
In this work, AlN whisker-reinforced (Zr, Hf)O 2 coating was prepared on SiC coated carbon/carbon composites by sol-gel and plasma spraying methods. Its cyclic ablation resistance was evaluated using an oxyacetylene torch with a heat flux of 2.38 MW/m 2 . After ablation, the coating showed apparently decreased crack sizes and quantity as compared with the one without AlN whisker addition, pointing out its better crack tolerance. Moreover, the coating had a thinner oxidized region based on the linear ablation rate (−0.042 µm/s), greatly lower than that of pure oxide coating (−0.922 µm/s). After detailed observation and characterization, probable protection mechanism was proposed.
研究领域:
材料科学
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航空航天工程
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高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2023
·
IF 6.2
Yi Cao,Piao Ruan,YuFeng Xue,Yue Cao,Huang He,Wenfeng Qiu
Nowadays, materials that possess high activity and natural oxygen vacancy have garnered significant attention as potential electrode materials for supercapacitors . In this study, we successfully prepared the Hf 6 Ta 2 O 17 (HTO) nanofibres (NFs) with an orthorhombic superlattice structure using the electrospinning technique and sintering process. The characterization results indicate that the HTO NFs synthesized at 750 °C show good micro nanostructures and outstanding electrochemical properties . To enhance its energy storage performance, additional oxygen vacancies (OVs) were introduced through a carbothermal treatment under an Ar atmosphere. Although longer reduction reaction times can produce more OVs, the integration of grain boundaries and the growth of grain size caused by large annealing times may limit its electrochemical performance. Therefore, the HTO NFs treated for 1 h (HTO/C-1) exhibited the maximum C s of 925 F·g −1 at 1 A·g −1 with a larger voltage window of 2.1 V. Furthermore, a symmetric supercapacitor fabricated by two reduced HTO NFs electrodes and 1 M Na 2 SO 4 solution, recorded as r-HTO NFs//r-HTO NFs. The device demonstrated excellent energy density of 73.3 Wh·kg −1 (at power density of 1050 W·kg −1 ) and a long cycling life (81.8% retained after 5000 cycles). These results suggest that the optimized reduction process can provide appropriate oxygen vacancies in HTO NFs, thereby effectively enhancing its performance.
研究领域:
材料科学
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能源存储
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高影响因子
JOURNAL OF FOOD COMPOSITION AND ANALYSIS
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2025
·
IF 4.6
Qianqian Liu,Qi Chen,Wenhao Zhang,Ru Liu,Dingxuan Li,Qingcui Chu
In this work, the porous nanomaterial zeolite imidazolate framework-67 (ZIF-67) and tributyl phosphate (TBP) were introduced to co-modify the hollow-fiber liquid-phase microextraction (HF-LPME) for the first time. The extract of five typical flavor enhancers (vanillin, o-vanillin, ethyl vanillin, vanillinol and vanilla acetone) could be directly injected for electrophoretic separation and amperometric detection. The obtained optimum extraction conditions were as followed: supported liquid membrane, tributyl phosphate containing 0.050 mg mL -1 of ZIF-67; donor phase, 10 mL (pH 4.00 adjusted by HCl); acceptor phase, 10 μL (0.20 M NaOH); stirring rate, 500 rpm; extraction temperature, 25 °C; and extraction time, 45 min. Based on the synergistic enrichment effect of ZIF-67 and TBP, this HF-LPME could provide the enrichment factors of 207(V-OH)-890 times (EVA) for the flavor enhancers. This method has been successfully used for the analyses of milk, milk powder and milk tea samples. The limits of detection were 0.15-3.0 μg L -1 (S/N=3), and the recovery data were in the range of 80.1-115.5%. This developed method is easy to operate and has low consumption of solvents and samples, providing a green alternative method for the detection of typical flavor enhancers in dairy products. Besides, the greenness and eco-friendliness of the proposed method was assessed using the green analytical procedure index and analytical eco-scale tools.
研究领域:
分析化学
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食品科学
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纳米技术
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分离科学
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电化学
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高影响因子
MATERIALS CHARACTERIZATION
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2026
·
IF 6.2
Jun Zhao,Xiang Ji,Peipei Wang,Leihua Xu,Peizhong Feng,Guozheng Lv,Changlin He,Xuanru Ren
A Hf-based borosilicate glass modification strategy is proposed to enhance the oxidation resistance of ZrB 2 -MoSi 2 ceramics. • Moderate HfO 2 addition forms in-situ dense Zr-Hf-Si-O multiphase glass layer, suppressing oxygen inward diffusion. • ZMGH30 sample shows 23.73% lower oxidation weight gain, 70.38% lower average oxidation rate, and 61.17% hardness retention. To address the issues of loose oxide scale and insufficient protective performance in ZrB 2 -MoSi 2 composite ceramics under ultra-high temperature oxidizing environments, caused by the volatilization of B 2 O 3 and the self-depletion of MoSi 2 , A novel Hf-based borosilicate glass modification strategy is proposed by this work. The effects of varying HfO 2 contents on the oxidation resistance and mechanical properties of the ceramics after oxidation at 1700 °C for 100 min were systematically investigated. The results indicate that, with an appropriate amount of HfO 2 modification, a continuous Zr-Hf-Si-O multiphase glass layer forms in situ during oxidation, significantly suppressing the inward diffusion of oxygen. Compared with the unmodified sample, the ZMGH30 sample exhibits a 23.73% reduction in oxidation weight gain, a 70.38% decrease in average oxidation rate, and an increase in hardness retention to 61.17%. Excessive HfO 2 leads to excessively high viscosity of the glass layer, Hf element agglomeration, and dendritic precipitation, thereby weakening the self-healing ability and deteriorating the oxidation resistance. A new approach for developing ultra-high temperature ceramics that combine excellent oxidation resistance and mechanical reliability is provided by this work.
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高影响因子
Materials Today Communications
·
2026
·
IF 4.5
Wei Gan,Can Jiang,Yao Wang,Min Ling,Shengfu Zhang
It is challenging to develop well-designed photocatalysts with high activity. In this work, TiO 2 nanotubes (TiO 2 -NTs，TNT) with well-morphology and high {001} facets exposure ratio were directly synthesized by H 3 PO 4 /HF-assisted two-step anodic oxidation. The results show that the addition of 3 wt% H 3 PO 4 and 0.5 wt% HF into the electrolyte facilitates the preparation of TiO 2 -NTs with an average crack density of 0 % and {001} facets exposure ratios up to 80.00 %. Moreover, the PO 4 3- and HPO 4 2- in the anode effectively hinder the generation of electron current and release of oxygen bubbles on the surface of Ti substrate, which reduces the surface cracks of TiO 2 -NTs. The F - in the electrolyte is adsorbed on the {001} facets of the TiO 2 -NTs, which decreases the energy of the O-Ti-O, thus achieving the purpose of high {001} facets exposure ratio. Ultimately, the excellent optical properties, in conjunction with the synergistic effect of {001} facets-selective orientation and O V , significantly enhanced the photocatalytic activity of TiO 2 -NTs, resulting in the removal of 90.32 % Rhodamine B in 120 min under visible light illumination. This work could shed light on the new approach to the rational design of high-efficiency TiO 2 -NTs-based photocatalysts.
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高影响因子
ACS Sustainable Chemistry & Engineering
·
2022
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IF 9.224
Hengyu Hao,Yuya Abe,Haixin Guo,Xiao Zhang,Richard Lee Smith Jr
Bifunctional Lewis (L) acid (Ni- or Hf-) site–Brønsted (B) acid catalysts designed to promote transfer hydrogenation reactions were prepared via hydrothermal and solvothermal methods using safe mixed solvents and sustainable precursors. By using N,N-dimethylformamide as a basis for the desired basicity, mixed solvents could be identified that allowed catalysts to be prepared with tunable ratios of Lewis to Brønsted acid sites (L/B). The as-prepared catalysts promoted transfer hydrogenation of furfural and ethanolysis to form ethyl levulinate (EL) using ethanol as a solvent and hydrogen donor source. Among the catalysts, sulfonated Hf-catalysts prepared with a cyclopentanone/formic acid mixed solvent (Hf-CPN/FA) with an L/B ratio of 6.4 gave 95% furfural conversion with 51.9% yield of EL, while the sulfonated Hf catalyst prepared with a cyclopentanone/γ-valerolactone mixed solvent (Hf-CPN/GVL) with a total Lewis and Brønsted acid site amount of 85.1 μmol/g gave 100% furfuryl alcohol (FAL) conversion with 72.5% yield of EL. Brønsted acid sites promoted reversible acetalization of furfural with ethanol into 2-furaldehyde diethyl acetal, while Lewis acid sites promoted furfural transfer hydrogenation into FAL and EL and further conversion into γ-valerolactone. The methods developed in this work eliminate dipolar aprotic solvents and harsh acids used in catalyst synthesis and allow sustainable production of EL from biomass-related chemicals.
研究领域:
化学工程
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催化
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绿色化学
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有机化学
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生物质转化
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高影响因子
NANOTECHNOLOGY
·
2018
·Vol. 30
·期 1
·015705
·
IF 3.404
Jianjun Wang,Yingxiong Zhang,Huilian Hao,Wenzhong Shen
Stable luminescent colloidal silicon (Si) nanocrystals (NCs) with sufficient surface protection are prepared through femtosecond laser ablation in organic solvent containing diverse concentrations of HF solution. The average size of Si NCs shows the decreasing tendency from 6.5 to 2.7 nm when the concentration of HF varies from 0 to 11.1 vol% (volume ratio). In line with the structural evolution, UV–visible absorption, photoluminescence (PL) excitation spectra, and time-resolved PL, we propose that room temperature blue emission peaks at 412 and 440 nm originate from alkyl-related radiative recombination centers. The enhanced PL quantum yield of colloidal Si NCs from 16.3% to 76.5% has been attributed to the effective passivation and suppression of non-radiative defect centers with increasing HF concentration from 0 to 11.1 vol%.
研究领域:
材料科学
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光学
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高影响因子
Solids
·
2025
·Vol. 6
·期 4
·66
·
IF 2.4
Chenxing Liao,Feng Zhou,Wei Xie,Liaolin Zhang
Mn4+-doped fluoride red phosphors are widely used in white LED lighting and display applications due to their excellent luminescent properties. However, their synthesis relies heavily on highly toxic aqueous hydrofluoric acid, which not only causes severe environmental and soil/water pollution but also makes it difficult to control the microstructure of the products due to the rapid reaction rate. In this study, low-melting-point NH4HF2was used as the molten salt, with KMnO4and MnF2as manganese sources, to synthesize the red phosphor K3AlF6: Mn4+via the molten salt method. After the reaction, impurities such as NH4HF2were removed by washing with a dilute H2O2solution. The microstructure, photoluminescence properties, thermal quenching behavior, and application in warm white light-emitting diodes (W-LEDs) of the K3AlF6: Mn4+phosphors were investigated. The results indicate that the phosphors prepared by this method consist of a single pure phase. By adjusting the molten salt content, the morphology of the product can be transformed from nanoparticle-like to nanorod-like structures. All products exhibit the characteristic red emission of Mn4+under blue and violet light excitation, with the optimally doped sample achieving an internal quantum efficiency (IQE) of 69% under blue light excitation. The combination of the obtained K3AlF6: Mn4+with the yellow phosphor YAG enabled the fabrication of W-LEDs. These W-LEDs achieved a color rendering index (Ra) of 86.8, a luminous efficacy (LE) of 77 lm/W, and a correlated color temperature (CCT) of 3690 K, along with excellent color stability under operating conditions.
研究领域:
材料科学
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光电子学
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固态化学
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发光材料
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LED技术
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高影响因子
危险品化学品经营许可证（带存储）