EUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY
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2015
·Vol. 117
·期 8
·1185-1191
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IF 1.812
Weiwei Cheng,Guoqin Liu,Xuede Wang,Xinqi Liu,Lu Jing
In this work, the kinetics of “in situ” epoxidation of soybean oil with H 2 O 2 (30% w/w), catalyzed by phosphotungstic heteropoly acid [π-C 5 H 5 N(CH 2 ) 15 CH 3 ] 3 [PW 4 O 16 ] (PHA) phase transfer catalyst and polyethylene glycol (PEG) as interfacial agent in dichloroethane, were investigated at 40, 50, 60, and 70°C. Assuming that the epoxidation reaction occurred in the pseudo-homogeneous catalytic system and the side reaction of epoxy ring cleavage was negligible, the results appeared that the epoxidation reaction of soybean oil in the presence of PEG was a second-order with respect to double bond concentration and a first-order to the H 2 O 2 concentration. The corresponding apparent activation energy (42.12 kJ/mol) was lower than that of PHA alone (49.23 kJ/mol), indicating that PEG could decrease the activation energy and speed up the epoxidation reaction of soybean oil. Practical applications: An environmentally friendly catalyst is eagerly needed to produce peroxided soybean oil for low yield and to prevent polluting the environment through the epoxidation of soybean oil with peracid. Phosphotungstic heteropoly acid phase transfer catalyst and polyethylene glycol improve the conversion and selectivity of the epoxidation reaction of soybean oil, and enhance its production efficiency. The activation energy of the soybean oil epoxidation reaction with H 2 O 2 catalyzed by phosphotungstic heteropoly acid (PHA) in the presence of polyethylene glycol (PEG) was lower than that of PEG alone, accounting for the results showing that the epoxy group band of the former (PHA + PEG) appeared quicker than the latter (PHA) in IR spectra.
研究领域:
化学工程
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2024
·
IF 20.2
Lei Zhang,He Jiang,Min Tang,Ying Jiang,Bing Tang,Hao Tan,Yuan Kong,Haibo Hu
Construction of robust protective cover on delicate active sites is a frequently-used scheme to enhance the durability of air-cathode catalyst working in harsh environment, thus the lifespan of rechargeable Zinc-air batteries (ZABs). Paradoxically, this would degrade the activity due to the constricted accessibility of active sites to reactants. Herein, carbon nanotubes with abundant mesoporous defects and Fe-N 4 species were elaborately designed to be multifunctional protective armor to encapsulate Ni 3 Fe nano-alloys (Ni 3 Fe@CNTs/Fe-N 4 ) for bifunctional oxygen electrocatalyst . In/ex-situ spectroscopy analysis and theoretical calculations reveal that the constructed mesoporous carbon defects effectively facilitate the multiphase mass transfer and the oxygen evolution reaction kinetics via strong electrons coupling with packaged Ni 3 Fe nano-alloys. Meanwhile, the synchronously introduced Fe-N 4 moieties could serve as oxygen reduction active sites. Thus, the obtained Ni 3 Fe@CNTs/Fe-N 4 hybrid electrocatalyst simultaneously exhibits remarkable bifunctional catalytic activity (E 1/2 =0.86/E j=10 =1.59 V vs RHE) and durability over 450 h in the chronoamperometric test at 1.59 V, endowing the assembled Zn-air batteries (ZABs) with a high power density (150 mW cm −2 ) and lifespan (307 h), much better than that employing benchmark Pt/C+RuO 2 mixed catalyst. This work demonstrates an innovative design route for the multifunctional armor to concurrently enhance the durability, activity and robustness of air-cathode-catalyst for ZABs.
研究领域:
材料科学
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电化学
·
能源存储与转换
✓ 已验证
产品关联
DOI
高影响因子
IONICS
·
2024
·
IF 2.4
Wang Lei,Tian Yanting,Li Zhanfeng,Zhu Jiping,Bian Tianlong
La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3−δ (LSCF) perovskite with good stability and high oxygen diffusion coefficient has been extensively studied as oxygen electrode in reversible solid oxide cells (RSOCs). Significant promotion of oxygen reaction kinetics of the LSCF oxygen electrode was achieved by the addition of Ca x Co 4 O 9+δ (CCOx, x = 3, 1.5) nano-catalysts in the present study. The La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3−δ -Ca 1.5 Co 4 O 9+δ (LSCF-CCO1.5) electrode exhibited the optimal electrochemical property among the LSCF-based electrodes and the lowest polarization resistance ( R p ) of 0.039 Ω·cm 2 was attained at 800 °C, which was ~ 97% lower than that of the LSFM electrode. Furthermore, the LSCF-CCO1.5 oxygen electrode also manifested excellent thermal cycling stability and alternating polarization durability. The hydrogen production rate of the LSCF-CCO1.5 electrolytic cell was 946 mL·cm −2 ·h −1 at 1.5 V at 800 °C, which was 2.6 times higher than that of the LSCF cell (362 mL·cm −2 ·h −1 ). The results certified the enhancement of electrochemical properties for LSCF oxygen electrode by the addition of CCOx nano-catalysts.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
Advanced Energy Materials
·
2024
·Vol. 14
·期 36
·2401509
·
IF 24.4
Han Yu,Guoliang Zhang,Dongmei Zhang,Ruonan Yang,Xia Li,Xiuqi Zhang,Gang Lian,Hua Hou,Zhanhu Guo,Chuanxin Hou,Xiaoyang Yang,Feng Dang
Although lithium–oxygen batteries (LOBs) hold great promise as future energy storage systems, they are impeded by insulated discharge product Li 2 O 2 and sluggish oxygen reduction reaction/oxygen evolution revolution (ORR/OER) kinetics. The application of a highly efficient cathode catalyst determines the LOBs performance. The d-band modulation and catalytic kinetics promotion are important concept guidelines for the performance enhancement of cathode catalysts. In this work, the homogeneous in-plane distortion-derived synergistic catalytic capability of an Ag 2 Mo 2 O 7 catalyst with modulated d-band centers and promoted ORR/OER kinetics is demontrated. The uniform elongation of Ag─O bonds and compression of Mo─O bonds in (020) plane leads to d-band splitting and d-band center optimization and delivers improved adsorption behavior for high ORR/OER capability. Furthermore, the spatial and energy overlap of Ag d xz and O 2 anti-bonding π * orbitals facilitate electron injection during ORR process and reduce the energy barrier for charge transfer and O 2 desorption during OER process, accelerating the ORR/OER kinetics. As a result, the (020) plane-exposed Ag 2 Mo 2 O 7 cathode exhibits ultralong cycle stability of 817 cycles at 500 mA g −1 and large specific discharge/charge capacities of 15898/15180 mAh g −1 . This work provides facile concept guidance for optimizing catalytic capability through controlled lattice distortion in cathode catalysts for LOBs.
研究领域:
材料科学
·
电化学
·
能量存储
·
催化
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）