JOM
·
2022
·Vol. 74
·期 9
·3548-3556
·
IF 2.597
Li Shuai,Yang Shenghai,Wang Changhong
Currently, the conventional halide synthesis method of preparing hafnium alkoxides [Hf(OR) 4 , R is an alkyl] has problems of inefficiency, a heavy CO 2 emission footprint, and substantial solid and gas waste, which severely hinders its wide deployment. Herein, we propose an electrodissolution-coupled Hf(OR) 4 synthesis system using an alcohol solvent and Hf metal as feedstock for the efficient, low-carbon and waste-free electro-synthesis of Hf(OR) 4 . The electrochemical behavior of the tetraethylammonium-hydrogen sulfate (Et 4 NHSO 4 )-based EHS process is investigated by cyclic voltammetry, linear sweep voltammetry, Tafel, and electrochemical impedance spectroscopy, complemented with SEM observation. The anodic hafnium dissolution/corrosion occurs inside the passive film while the cathodic ethanol dehydrogenation occurs in a two-stage pathway. Tafel extrapolation and numerical fitting analysis acquires important kinetics parameters, such as corrosion current density, exchange current density, and apparent activation energy as well as solution, polarization and “Warburg” resistances, etc. This work can provide theoretical guidance for the efficient operation of EHS.
研究领域:
材料科学
·
电化学工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Xian Shi,Xinyi Xing,Mengya Ruan,Qichun Wei,Ying Guan,Hui Gao,Siquan Xu
Efficient and green catalysis of cellulose to 5-hydroxymethylfurfural (HMF) is currently a challenge that needs a breakthrough. In this study, a series of inexpensive (x)SO 4 2- /HfO 2 heterogeneous catalysts were prepared and exhibited superior catalytic performance for conversion of cellulose into HMF in the green water-tetrahydrofuran monophasic system (H 2 O-THF). An optimal HMF yield of 54% was acquired through detailed evaluation of reaction conditions. Various analyzes including ICP-OES, XRD, SEM, TEM, FTIR, N 2 adsorption–desorption isotherm, XPS, TG, NH 3 -TPD and Py-FTIR were applied to inspected the physicochemical characteristics of the (x)SO 4 2- /HfO 2 catalysts. Meanwhile, the recyclability of the catalyst and the by-products generated during the reaction process were studied and captured, respectively. The results presented herein show that the catalytic system of (30%)SO 4 2- /HfO 2 catalyst combined with H 2 O-THF monophasic solvent is advanced, and it can be both green and efficient without the presence of other additives and promoters, and has great potential in the future.
研究领域:
化学工程
·
可再生资源转化
✓ 已验证
产品关联
DOI
高影响因子
COLLOIDS AND SURFACES B-BIOINTERFACES
·
2024
·
IF 5.4
Mingyue Cui,Zhe Tang,Zahoor Ahmad,Chunshu Pan,Yuguang Lu,Kamran Ali,Shuqi Huang,Xiaoqing Lin,Abdul Wahab,M. Zubair Iqbal,Xiangdong Kong
Precise diagnosis of complex and soft tumors is challenging, which limits appropriate treatment options to achieve desired therapeutic outcomes. However, multifunctional nano-sized contrast enhancement agents based on nanoparticles improve the diagnosis accuracy of various diseases such as cancer. Herein, a facile manganese-hafnium nanocomposites (Mn 3 O 4 -HfO 2 NCs) system was designed for bimodal magnetic resonance imaging (MRI)/computed tomography (CT) contrast enhancement with a complimentary function of photodynamic therapy. The solvothermal method was used to fabricate NCs, and the average size of Mn 3 O 4 NPs and Mn 3 O 4 -HfO 2 NCs was about 7 nm and 15 nm, respectively, as estimated by TEM. Dynamic light scattering results showed good dispersion and high negative (-33 eV) zeta potential, indicating excellent stability in an aqueous medium. Mn 3 O 4 -HfO 2 NCs revealed negligible toxic effects on the NCTC clone 929 (L929) and mouse colon cancer cell line (CT26), demonstrating promising biocompatibility. The synthesized Mn 3 O 4 -HfO 2 NCs exhibit significant enhancement in T 1 -weighted magnetic resonance imaging (MRI) and X-ray computed tomography (CT), indicating the appropriateness for dual-modal MRI/CT molecular imaging probes. Moreover, ultra-small Mn 3 O 4 -HfO 2 NCs show good relaxivities for MRI/CT. These nanoprobes Mn 3 O 4 -HfO 2 NCs further possessed outstanding reactive oxygen species (ROS) generation ability under minute ultraviolet light (6 mW·cm −2 ) to ablate the colon cancer cells in vitro. Therefore, the designed multifunctional Mn 3 O 4 -HfO 2 NCs were ideal candidates for cancer diagnosis and photodynamic therapy.
研究领域:
医学影像学
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纳米医学
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肿瘤学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
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
·
能源存储
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Hao Fu,Qinghua Zhao,Yuqi Zhang,Xichao Dong,Xingang Luan,Laifei Cheng
The thin-film electrode, as the core unit of wireless passive surface acoustic wave sensors, undertakes the signal conversion function. However, finding materials for thin-film electrodes that endure high temperatures while retaining excellent conductivity remains a formidable challenge. In this research, a series of SiHfBCN-based films doped with different fillers were fabricated via the polymer-derived ceramic method. Subsequently, the effect of film microstructure on room- and high-temperature conductivity was studied. Results showed the sole MoB 2 -doped film demonstrated the best electrical conductivity at room temperature. In contrast, adding CNTs lowered film conductivity due to filler agglomeration. Nevertheless, higher film pyrolysis temperatures built better conductive networks. At high temperatures, SiHfBCN-based films exhibited much lower resistivity compared to room temperature, with a minimum of 0.1 Ω cm. Moreover, after the high-temperature test, the films still retained a dense surface morphology. These findings strongly suggest SiHfBCN-based films have great promise and application potential for high-temperature electrodes.
研究领域:
材料科学
·
无机非金属材料
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高温功能材料
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电子器件材料
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陶瓷工程
✓ 已验证
DOI
高影响因子
ENERGY
·
2024
·
IF 9
Xian Shi,Wanni Liu,Xinyi Xing,Weiwei Shu,Rui Weng,Junhang Sun,Ying Guan,Hui Gao,Gaojin Lyu,Kai Huang,Zengyong Li,Mengya Ruan,Siquan Xu
5-hydroxymethylfurfural (HMF) is a platform compound with great potential, and solid acid-catalyzed lignocellulosic carbohydrate components into HMF is a viable biomass valorization strategy. Herein, hafnium-anchored dendritic mesoporous silica nanospheres (Hf-DMSNs) with three-dimensional center-radial structures were synthesized via an in-situ co-assembly method. Characterization revealed that the acid properties and particle size of Hf-DMSNs could be regularly customized and that they acted as bifunctional catalysts capable of driving glucose (190 °C, 3 h) and cellulose (210 °C, 4 h) to achieve the desired HMF yields of 71 % and 50 %, respectively. Owing to the appropriate acidity, high accessibility, and anchored active site, the recycling of Hf-DMSNs catalyst lasted for more than twenty times with slight activity loss, which is eye-catching. Meanwhile, the intermediates detected during the conversion process confirmed that the HMF formation from cellulose components under the Hf-DMSNs catalysis was a cascade reaction consisting of three basic steps: hydrolysis, isomerization, and dehydration. The findings in this study provide a reference for the utilization of biomass-derived carbohydrates into HMF via heterogeneous catalysis.
研究领域:
化学工程
·
催化材料科学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2025
·
IF 9
Xiaofan Ding,Long Chen,Yaolin Zhao,Jing Zhao,Songtao Xiao
The capture and separation of uranium and thorium from acidic nuclear waste streams are imperative for safeguarding the environment and human well-being. Metal-organic frameworks (MOFs), an emerging class of porous materials, offer considerable potential for U(VI)/Th(IV) adsorption owing to their customizable pore size and processability. Nonetheless, the development of MOFs with robust adsorption capabilities for U(VI)/Th(IV) in acidic conditions poses a significant challenge. In this study, we introduce a feasible MOF design approach: the integration of high-valent metal centers with oxygen-rich organic ligands. Employing this strategy, we have successfully engineered a novel MOF adsorbent, SU-102(Hf), comprising hafnium-based metal clusters and ellagic acid as the organic linker. In a 0.3 M nitric acid environment, SU-102(Hf) demonstrates outstanding chemical stability and exhibits a high adsorption capacity for both uranium (27.38 mg g −1 ) and thorium ions (32.03 mg g −1 ), which represent a record of simultaneous adsorption capacity of uranium and thorium binary components by MOFs in a highly acidic environment (0.3 M HNO 3 ). Simultaneously, SU-102(Hf) also displays rapid adsorption kinetics, excellent selectivity, and recyclability for U(VI)/Th(IV) separation at pH = 3. Experimental investigations and theoretical calculations further unravel the adsorption mechanisms and key differences for Th(IV) and U(VI) ions.
研究领域:
环境化学
·
放射化学
·
材料科学
·
分离科学
·
核能工程
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2018
·
IF 11.698
Hu Li,Tingting Yang,Zhen Fang
The use of organic chemicals derived from renewable sources to synthesize functional solid materials for heterogeneous catalysis is of great significance. Herein, a new porous and acid-base bifunctional hybrid (FDCA-Hf) was designed and prepared by simple assembly of biomass-derived 2,5-furandicarboxylic acid (FDCA) with hafnium (Hf) under template-free conditions. The resulting FDCA-Hf hybrid with mesopores centered at 6.9 nm, moderate surface area (365.8 m 2 /g) and acid-base couple sites (density: 0.51 vs 0.97 mmol/g, acid/base molar ratio: 0.53), could selectively catalyze the Meerwein-Ponndorf-Verley reduction of carbonyl compounds under mild reaction conditions (as low as 90 °C in a short time of 1 h), especially of ethyl levulinate to γ -valerolactone, in quantitative yields (95–100%) and relatively higher reaction rate (e.g., turnover frequency: 2.28 h −1 ) compared to other catalysts. Moreover, the efficient simultaneous (trans)esterification of Jatropha oils with high acidic values to biodiesel (up to 98% yield) could also be achieved over FDCA-Hf with robust acid-base catalytic sites. The FDCA-Hf hybrid was highly stable due to the presence of robust metal-organic framework and could be resued with no decline in activity. Further studies demonstrated that the synergistic role of Lewis acid-base couple species (Hf 4+ –O 2− ) and Brønsted acidic species ( OH) of FDCA-Hf contributed greatly to its pronounced catalytic activity.
研究领域:
催化化学
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材料科学
·
可再生资源利用
✓ 已验证
产品关联
DOI
高影响因子
POWDER TECHNOLOGY
·
2013
·
IF 2.024
Gang Wang,Rujie He,Feng He
It has been well accepted that polyacrylic acid (PAA) is an effective dispersant for metal diborides (such as ZrB 2 ) in aqueous media. However, when dispersing HfB 2 powder, the dispersing effect is reduced significantly. In this work, a second dispersant, ammonium citrate, was used to resolve this problem. It was found that a PAA–ammonium citrate binary dispersant system could effectively enhance the zeta potential , increase the PAA adsorption content, and improve the stability of HfB 2 . The apparent viscosities of the suspensions were also investigated. Results showed that the PAA–ammonium citrate binary dispersant system was effective for improving the dispersion of HfB 2 particles in aqueous media.
研究领域:
材料科学
·
化学工程
·
胶体科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2021
·
IF 6.609
Guo Qiu,Biaohua Chen,Ning Liu,Chongpin Huang
5-Hydroxymethylfurfural (5-HMF), an important and value-added platform chemical, has inspired increasing attention. In this study, hafnium-tin composite oxides (Sn-HfO 2 ) were prepared by one-pot coprecipitation process and used as effective synergistic catalysts for 5-HMF synthesis from the conversion of glucose. Pyridine-FTIR results reveal that Sn-HfO 2 catalysts have strong Lewis and weak Brønsted acid sites. With 0.5Sn-HfO 2 as the catalyst, the highest yield of 5-HMF obtained from glucose was 75.5% with 99.5% conversion at 170 °C for 2 h in a methyl isobutyl ketone (MIBK)/water biphasic system. Furthermore, the catalytic system also possesses excellent performance in converting other carbohydrates. The catalysis mechanism for the isomerization of glucose to fructose was explored by the density functional theory (DFT) method, indicating that Lewis acidic Hf active sites and proton mediator Sn-O species synergistically catalyzed the isomerization process, effectively lowering the reaction energy barrier. The cooperative action of terminal Hf-OH and Sn-OH also facilitated the formation of 5-HMF in fructose dehydration. 0.5Sn-HfO 2 could be reused for four runs without significant loss of catalytic activity. This approach provides the feasibility of composite oxides as synergistic catalysts for carbohydrate conversion to 5-HMF.
研究领域:
化学工程
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Weijia Guo,Yiming Yang,Zhiyu Ma,Yutian Lu,Zhenxing Yue
Microwave dielectric ceramics with high relative permittivity ( ε r ) are commonly used for the miniaturation of microwave devices. The dielectric loss mechanism of microwave dielectric ceramics , as well as the property modification, has been a concerned topic among scholars. Herein, the lattice structure, defects, and broadband dielectric response of Zr 4+ and Hf 4+ substituted Ba 4 Sm 9.33 Ti 18 O 54 (BST) ceramics are systematically examined. The negative temperature coefficient of resonant frequency ( τ f ) of BST ceramics can be tuned to near zero via ion substitution, owing to the Sm 2 Ti 2 O 7 second phase with a large positive τ f . Optimal microwave dielectric properties of ε r = 81.3, Q × f = 10,800 GHz, and τ f = −4.6 ppm/°C are achieved. The lattice vibration behavior and defect concentration are analyzed by Raman spectra and thermally stimulated depolarization currents (TSDC), respectively. The increasing volume of the unit cell and TiO 6 octahedra, which is because of the large-radius substitution ions, leads to an increase in lattice vibration damping factor and the generation of more oxygen vacancies ( V O ∙ ∙ ). Therefore, the dielectric losses in the microwave and terahertz (THz) bands increase after substitution. Meanwhile, the low-frequency dielectric losses at high temperatures also increase due to the weak restraint of carriers by the lattice. The broadband loss mechanism of Zr 4+ and Hf 4+ substituted BST ceramics related to lattice vibration and defects might be referenced for developing low-loss dielectric ceramics.
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
高影响因子
GREEN CHEMISTRY
·
2019
·Vol. 21
·期 10
·2739-2751
·
IF 9.405
Naseeb Ullah,Atheer Hameid Odda,Kuang Liang,Miza Ali Kombo,Shafaq Sahar,Liu-Bo Ma,Xiao-Xiang Fang,An-Wu Xu
The catalytic fractionation of lignin in a native lignocellulose matrix is crucial to the comprehensive achievement of sustainable and green chemicals. Herein, we prepared a novel metal–acid bifunctional nanocomposite of finely scattered metallic Ru nanoclusters (NCs) sustained on porous hafnium phosphate nanoplates (α-HfP NPs) to effectively depolymerise lignocellulosic biomass. A native lignin fraction of pine lignocellulose was promptly depolymerised into 19.86 wt% yield (lignin based) of valuable phenolic monomers (with dihydroeugenol as the main compound with high selectivity) and few cyclic ketones through one-pot catalytic reductive fractionation under mild conditions (190 °C, 3.5 MPa H2). Detailed scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, and temperature-programmed desorption ammonia investigation correlated with the obtained results revealed that the metal–acid synergistic influence and the presence of Brønsted acid sites in the support for dehydration and the well-dispersed metallic role of Ru NCs for hydrodeoxygenation were responsible for the cleavage of lignin–carbohydrate (ester and ether linkages) bonds. Moreover, treating commercial lignin as a substrate in an organic solvent generated 4-hydroxy-3-methoxybenzaldehyde (vanillin) in high yield, as well as other functionalised phenolic monomers up to 85% selectivity, illustrating the high susceptibility of Ru/α-HfP NPs towards C–O bond cleavage through reductive fractionation. Multiple recycling tests of the catalyst were performed without any apparent loss of activity. Overall, this report highlighted the potential of the synthesis strategy of the metal–acid supported catalyst to immediately depolymerise untreated biomass and can thus encourage the green, cost-efficient, large-scale production of intermediate chemicals.
研究领域:
化学工程
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生物质能
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）