CORROSION SCIENCE
·
2025
·
IF 8.5
Huan Guo,Bingzhu Wang,Ruifeng Li,Cheng Su,Jixiang Dai,Yong She,Yongzhong Zhao,Jianjun Sha
Aiming at forming a stable ablation layer for hafnium-based ultrahigh-temperature ceramics under ablation environment, in this work, the Ta-based ceramic was introduced into the Hf-based ceramic, and the effect of Hf/Ta molar ratios on the ablation response behavior and mechanism of (Hf, Ta)B 2 -(Hf, Ta)C-SiC ceramics was investigated. It was found that the introduction of Ta could form a continuous and dense ablation layer. When Hf/Ta= 0.9:0.1, the ceramic composite presented excellent ablation resistance, and the linear ablation rate was −0.083 μm/s, which was only 5.85 % of that of Hf-based ceramics (HfB 2 -HfC-SiC). The excellent ablation resistance attributed to that the ablation products (Ta 2 O 5 and Hf 6 Ta 2 O 17 ) could strongly bonded to the substrate, which was conducive to enhance the stability of the ablation layer.
研究领域:
材料科学
·
航空航天工程
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2024
·
IF 0
Li Danni,Guo Xin,Shao Xiang,Zhou Anhui,Zhu Lin,Zhang Yuting,Li Binbin,Du Yan,Cao Limei,Yang Ji
The electrochemical advanced oxidation process (EAOP) has shown significant promise in the field of refractory organic wastewater treatment due to its high efficiency and environmentally friendly nature. In this study, Ti/Sb-SnO 2 electrodes with varying proportions of Hf were prepared using the sol–gel method. The addition of Hf transformed the original collapsing and broken surface into a flat and regular surface. The results demonstrated that Ti/Sb-SnO 2 -Hf electrode doped with 6% Hf exhibited a higher oxygen evolution potential (OEP) and excellent stability. The OEP increased from 2.315 V without Hf-doping to 2.482 V, and the corresponding actual life was 321.05% higher than that without Hf. The current density (5–40 mA·cm −2 ), electrolyte concentration (0.02–0.2 mol·L −1 ), pH (3–11), and initial pollutant concentration (5–80 mg·L −1 ) were evaluated to confirm the tetracycline (TC) degradation characterization of Ti/Sb-SnO 2 -6%Hf electrodes. It was concluded that under the optimal degradation conditions, the removal rate of TC could reach 99.66% within 2 h. The degradation of TC follows first-order reaction kinetics. The oxidative degradation of TC was achieved through indirect oxidation, with ·OH playing a dominant role. TC’s electrochemical oxidation degradation pathway has been proposed: Based on LC–MS results, three main pathways are speculated. During the electrocatalytic oxidation process, decarboxylation, deamidation, and ring-opening reactions occur under ·OH attack, producing intermediate compounds with m/z values of 427, 433, 350, 246, 461, 424, 330, 352, 309, 263, and 233. These intermediates are further oxidized to intermediate compounds with an m/z value of 218. This work introduces a new efficient anode electrochemical catalyst for the degradation of TC, providing a strategy for industrial applications.
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
PubMed
POLYMER DEGRADATION AND STABILITY
·
2020
·
IF 4.032
Junchao Zhao,Yangyang Fu,Song Lu,Neng Tao,Zhitao Yin,Muhammad Usman Shahid,Heping Zhang
Perfluoro copolymers (PFCPs) with PFD (long chain -(CF 2 ) 7 CF 3 moiety) have a wide range of applications, such as hydrophobic and oleophobic modification of dry chemicals suppressants. However, high fluorine contents may produce much HF in thermal environments. In this study, a newly designed perfluoro copolymer (DPFCP) was synthesized and its application, pyrolysis and HF production were investigated. The pyrolysis of DPFCP could be divided into three stages, whereas the gas mainly released at the second stage, including CH 2 O, CO 2 , H 2 O, C x H y , C x H y F z , NH 3 , HF. A tube furnace was used to heating DPFCP to collect residual products and HF. The results indicated that HF was mainly produced under 370 °C.
研究领域:
材料科学
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环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Arabian Journal of Chemistry
·
2023
·
IF 6
Hongru Zhao,Chengqiang Hu,Na Sui,Xinyu Liu,Junlian Wang
Zr/Hf separation has always been a great challenge. Although the methyl isobutyl ketone (MIBK)-thiocyanic acid (HSCN) extraction system selectively extracts Hf over Zr and can realize Zr/Hf separation, it has the following disadvantages: it has a strong smell; it is easy to burn; and there is large loss of extractant during extraction due to the low boiling point (115.7 °C), low flashing point (13 °C), and high solubility of MIBK in water (1.7 % at 25 °C). In this study, Zr/Hf separation performance by MIBK homologues — of which one side of C = O is iso pentyl, iso hexyl, n -pentyl, n -hexyl or n -heptyl, while the other side are all methyl — were studied and compared with MIBK. Effects of HSCN pre-extraction, HCl concentration, NH 4 SCN concentration on Zr, Hf extraction and separation performance were investigated. Relationships between methyl alkyl ketone structure and their Zr/Hf separation performance were revealed. A new Zr/Hf separation system MNPK (methyl n -pentyl ketone)-HSCN was found. MNPK has a higher boiling point (151 °C), a higher flashing point (47 °C) and a lower solubility in water (0.43 % at 20 °C) than MIBK. Compared to MIBK, it is safer, more friendly operation environments and less extractant loss during extraction. MNPK has as fast extraction kinetics as MIBK. It also has good anti-emulsification performance. Its maximum β Hf/Zr can reach to 12.61. The loaded Zr and Hf in MNPK have very similar stripping behaviors with those loaded in MIBK by HCl and H 2 SO 4 solutions, respectively. MNPK is the most possible candidate to replace MIBK from HSCN media in Zr/Hf separation industry.
研究领域:
化学工程
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2017
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IF 3.133
Pengcheng Chen,Siyi Jing,Yanhui Chu,Pinggen Rao
Residual oxide impurities in high-temperature structural ceramics containing carbon-based reinforcements can react with the reinforcements during sintering to weaken their toughening effect. To eliminate such effect, a simple HF treatment technique is proposed. In this work, SiC ceramics and carbon nanotubes (CNTs)/SiC ceramic composites were fabricated by spark plasma sintering . The results showed that, after HF treatment, the structure of incorporated CNTs in the composites was unaffected and a slight improvement of relative density was fulfilled. The fracture toughness improvement of the composites from 4.4 ± 0.4 MPa m 1/2 to 5.4 ± 0.5 MPa m 1/2 with indentation method (IM) after HF treatment was also observed due to crack branching, CNT pull-out and crack bridging.
研究领域:
材料科学
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工程学
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产品关联
DOI
高影响因子
Environmental Science-Nano
·
2023
·Vol. 10
·期 11
·3149-3155
·
IF 7.3
Hang Zhang,Kang Liu,Yingkang Chen,Xiaojian Wang,Hongmei Li,Junwei Fu,Liyuan Chai,Zhang Lin,Min Liu
CF4 is the most emitted perfluorocarbon (PFC) and possesses a great global warming potential (GWP) of 7390 with a lifetime of 50 000 years. Catalytic hydrolysis is a promising method for reducing CF4 emissions; however, the HF product can easily poison the catalyst, resulting in poor stability. In this study, a strategy for resisting HF corrosion by enhancing the order of aluminum-oxide polyhedron is originally demonstrated. HF corrosion experiments indicated that the Al2O3 catalysts with a higher order of aluminum-oxide polyhedron exhibited better resistance to HF corrosion (HF corrosion reaction rate k2, γ-Al2O3: 1.34 × 10−3, θ-Al2O3: 1.90 × 10−5, and α-Al2O3: 1.30 × 10−5). The obtained θ-Al2O3 achieved a lifetime of 100 h with 100% decomposition of CF4 at 750 °C, which is ∼20 times that of the γ-Al2O3 catalyst, and α-Al2O3 was inactive for CF4 decomposition. Theoretical calculations also demonstrated that θ-Al2O3 had lower adsorption and higher reaction barriers with HF than those of γ-Al2O3, proving the high stability of θ-Al2O3. This study provides a new inspiration for the development of efficient and stable CF4 decomposition catalysts.
研究领域:
环境科学
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材料科学
✓ 已验证
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2017
·
IF 3.387
Zhangxing He,Yingqiao Jiang,Wei Meng,Fengyun Jiang,Huizhu Zhou,Yuehua Li,Jing Zhu,Ling Wang,Lei Dai
In order to improve the electrochemical performance of the positive graphite felt electrode in vanadium flow redox battery, a novel method is developed to effectively modify the graphite felt by combination of etching of HF and oxidation of H 2 O 2 . After the etching of HF for the graphite felt at ambient temperature, abundant oxygen-containing functional groups were further introduced on the surface of graphite felt by hydrothermal treatment using H 2 O 2 as oxidant. Benefiting from the surface etching and introduction of functional groups, mass transfer and electrode process can be improved significantly on the surface of graphite felt. VO 2+ /VO 2 + redox reaction on the graphite felt modified by HF and H 2 O 2 jointly (denote: GF-HF/H 2 O 2 ) exhibits superior electrochemical kinetics in comparison with the graphite felt modified by single HF or H 2 O 2 treatment. The cell using GF-HF/H 2 O 2 as the positive electrode was assembled and its electrochemical properties were evaluated. The increase of energy efficiency of 4.1% for GF-HF/H 2 O 2 at a current density of 50 mA cm −2 was obtained compared with the pristine graphite felt. The cell using GF-HF/H 2 O 2 also demonstrated higher discharge capacity. Our study revealed that HF/H 2 O 2 treatment is an efficient method to enhance the electrochemical performance of graphite felt, further improving the comprehensive energy storage performance of the vanadium flow redox battery.
研究领域:
材料科学
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电化学
·
能源存储
✓ 已验证
DOI
高影响因子
JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY
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2022
·Vol. 332
·期 7
·2473-2485
·
IF 1.754
Wang Junlian,Liu Hui,Zhao Hongru,Wang Huajun
A new Zr/Hf separation system was developed with a novel unsymmetrical dialkylphosphinic acid extractant ( n -octyl)(2,4,4'-trimethylpentyl)phosphinic acid (INET-1). It selectively extracts Hf over Zr, and shows much better Zr/Hf separation efficiency than organophosphorous acid Cyanex 272. The Zr and Hf extraction reactions at acidities of < 2 mol/L H 2 SO 4 and > 5.5 mol/L H 2 SO 4 are revealed, respectively. An organic phase with 10 mmol/L INET-1 can load > 290 mg/L of Hf at 1 mol/L H 2 SO 4 . Acidic H 2 SO 4 solutions with concentration of 3.0–4.5 mol/L is a good Zr scrubbing agent.
研究领域:
化学工程
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Wanhong Yu,Guifang Li,Changwan Sun,Jianquan Zhang,Li Yang,Yichun Zhou
In this paper, we propose an effective method for doping WC into Ta-Hf-C ceramics to significantly enhance their densification and mechanical properties. An increasing WC doping amount from 0 to 20 at.%, enhances the densification of Ta-Hf-C ceramics from 92.4 % to 99.1 %. This is mainly due to the fact that the doping of WC effectively removes the harmful oxygen impurities from the ceramics, thereby increasing their sintering activity. Furthermore, the doping of WC plays an active role in the mechanical properties of the ceramics. The Ta-Hf-C doped with 15 at.% WC has the highest value of 36.41 GPa for nano-hardness due to the solid solution strengthening mechanism, while the highest Vickers hardness (38.75 GPa) and fracture toughness (3.76 MPa m 1/2 ) appear in Ta-Hf-C doped with 20 at.% WC. The main toughness mechanism is W segregation at the grain boundary, enhancing grain boundary strength .
研究领域:
材料科学
·
力学
✓ 已验证
产品关联
DOI
高影响因子
Materials Today Energy
·
2022
·
IF 9.257
Changqing Tian,Qiang Huang,Daofu Wu,Junan Lai,Fei Qi,Nan Zhang,Wenxia Zhang,Xiaosheng Tang
The lead halide perovskites have broad application prospects in the fields of optoelectronics and photocatalysis . However, their toxicity and limited stability are the main obstacles restricting their large-scale photocatalytic applications. In order to solve these problems, a set of lead-free stable Cs 2 XCl 6 (X = Hf, Zr, Te) perovskite microcrystals were synthesized via a solvothermal solution. For the first time, the Cs 2 XCl 6 (X = Hf, Zr, Te) perovskite microcrystals were employed as efficient photocatalysts for the conversion of CO 2 into CO and CH 4 . Among them, the Cs 2 TeCl 6 microcrystals showed the best photocatalytic performance under light irradiation for 3 h, while the yields of CO and CH 4 were 284.4 μmol/g and 48.96 μmol/g respectively. Our strategy may provide a new idea for the CO 2 photoreduction based on lead-free halide perovskites.
研究领域:
材料科学
·
光催化
·
环境科学
✓ 已验证
DOI
高影响因子
CATALYSIS LETTERS
·
2020
·Vol. 151
·期 7
·1984-1992
·
IF 2.482
Wu Ningxin,Zhang Manling,Pan Xiaomei,Zhang Jin,Gao Lijing,Xiao Guomin
Abstract The production of 5-hydroxymethylfurfural (HMF) from cellulose is of great significance for the high-value utilization of biomass, although this route currently faces the challenge of low efficiency. In the present work, a series of effective (x)Hf/ZSM-5 catalysts were developed for HMF production from cellulose, and analyzed by BET, XRD, SEM, ICP, NH 3 -TPD, Py-FTIR techniques. Driven by the (5)Hf/ZSM-5 catalyst, HMF with a yield of up to 67.5% and 17.2% of furfural are simultaneously obtained from cellulose in the H 2 O (NaCl) /THF biphasic system. Moreover, after four consecutive cycles, (5)Hf/ZSM-5 catalyst still maintained part of its catalytic activity. The 67.5% HMF yield achieved herein is one of the highest yields achieved in the conversion reaction using cellulose as a substrate, and the catalytic performance of the H 2 O (NaCl) /THF system containing the (5)Hf/ZSM-5 catalyst is even comparable to that of the expensive ionic liquid system. This result reflects the application prospect of (5)Hf/ZSM-5 catalyst in the future industrial production process of HMF. Graphic Abstract
研究领域:
化学工程
·
催化
·
生物质转化
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2022
·
IF 7.392
Menghan Qin,Yumiao Shi,Dingkun Lu,Jingjing Deng,Guoyue Shi,Tianshu Zhou
Due to the excessive use, cephalosporin antibiotics have been detected in various aquatic environments, which may result in environmental and health concern. In this study, bimetallic metal–organic frameworks (MOFs), Hf-UiO-66 and Ti-UiO-66, were successfully designed and obtained via post-synthetic method from UiO-66 for the adsorption of cefoperazone. A serious of adsorption experiments were investigated. The adsorption kinetics and isotherms demonstrated that the adsorption process followed pseudo-second-order kinetic model and Langmuir isotherm model. Hf/Ti-UiO-66 exhibited much better adsorption performance than the undoped UiO-66. Particularly, Hf-UiO-66 had the highest adsorption capacity (346.0 mg g −1 ). With the introduction of Hf or Ti, the chemical coordination environment changed, which resulted in defective structures of MOFs. Such defective structures increased the adsorption active sites, changed the surface charges and enlarged pores. Based on the characterization by FT-IR, XPS, and zeta potential, it was identified that the electrostatic attraction, π-π stacking, hydrogen bonding and metal complexation were the driving force for the high adsorption capacity of the bimetallic MOFs. The as-prepared MOFs displayed good stability and reusability. This work provides a great prospect for the design and application of bimetallic defective MOFs in cephalosporins removal in environmental water.
研究领域:
环境科学
·
材料科学
✓ 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）