CHEMICAL ENGINEERING SCIENCE
·
2024
·
IF 4.1
Yu Xie,Wangyang Wang,Jiale Cui,Hui Li,Kang Cheng,Qinghong Zhang,Ye Wang
The oxidative coupling of methane (OCM) into C 2−3 hydrocarbons is still limited to a few types of catalysts with low product yield. Herein, we reported our discovery that a K 2 SO 4 -promoted TiO 2 catalyst can effectively catalyze the OCM reactions with a C 2−3 yield of up to 26 %, which is comparable to the classical Mn-NaWO x /SiO 2 catalyst. Besides, this catalyst not only exhibits promising stability for at least 200 h without signs of deactivation under typical OCM conditions but also demonstrates high sulfur-resistance performance, outperforming most reported catalysts. We have evidenced that K + ions are responsible for increasing the surface basicity of rutile TiO 2 , thus benefiting C 2−3 selectivity. The presence of SO 4 2− can prevent the formation of potassium titanates, which catalyze the over-oxidation of CH 4 . The surface lattice oxygen species are confirmed to be the active sites for selective CH 4 activation, while the chemisorbed oxygen species catalyze the combustion of CH 4 to CO 2 .
研究领域:
化学工程
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2024
·
IF 4.3
Shu-Hua Han,Dan-Dan Huang,Zhang-Jian Cheng,Ai-Lin Liu,Yun Lei
Most known chemiluminescence (CL) systems are flash-type that generate weak luminescence and decline quickly after dozens of seconds, while the glow-type CL systems have stable emission for an extended period to achieve accurate quantitation. In this work, a long-term CL system based on hydrazine-hydrate (N 2 H 4 ·H 2 O) modified carbon quantum dots (N-CQDs) as a luminescent probe, with K 2 S 2 O 8 and H 2 O 2 as co-reactants, was proposed. The CL emission enhanced by H 2 O 2 increased 18-fold more than that of N-CQDs and K 2 S 2 O 8 direct reaction, and decayed by 5% of the maximum intensity over 700 s. In the reaction system, K 2 S 2 O 8 and H 2 O 2 co-reactants can promote each other to continuously generate corresponding radicals (•OH, O 2 •− , 1 O 2 ), which in turn trigger the CL emission of N-CQDs. This phenomenon was identified as the primary cause for the production of persistent CL. In addition, a stable and selective CL sensor based on the N-CQDs-K 2 S 2 O 8 -H 2 O 2 CL enhancing system was developed for ascorbic acid quantitation in the linear range from 0.1 to 10.0 mM with a detection limit of 0.036 mM. The method has been applied to the analysis of tablet samples and holds potential in pharmaceutical analysis field.
研究领域:
分析化学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENERGY & FUELS
·
2022
·
IF 4.654
Zhi-long Xu,Hong-bo Huang,Cai-ling Liu,Shao-hua Luo,Qing-long Wang,Li-guo Jin,Gui-dong Dong,Hai-long Lu
For SnO2 that was used as an anode material for potassium-ion batteries (KIBs), the theoretical capacity is rarely high. However, due to the excessively huge volume expansion of SnO2 in the electrode reaction, the battery capacity decreases sharply, thus impeding its practical application. Here, potassium stannate and glucose were dissolved in the hydrothermal phase and dispersed evenly through a one-step hydrothermal method and then calcined and carbonized at a high temperature in an argon atmosphere to obtain a SnO2@C composite. To obtain an electrode with better performance, SnO2@C/MCB (micrometer carbon ball) composites were synthesized by a similar method. SnO2@C/MCB exhibited a high initial reversible capacity, splendid rate property, and cycling performance in KIBs (the initial capacity remains at 57.2% after 450 cycles). Compared with the SnO2@C material, the SnO2@C/MCB electrode has a higher electrical conductivity, smaller volume change, and better potassium storage capacity.
研究领域:
材料科学
·
能源存储
✓ 已验证
DOI
高影响因子
FUEL
·
2021
·
IF 6.609
Mingwei Xia,Wei Chen,Jing Wu,Yingquan Chen,Haiping Yang,Xu Chen,Danchen Zhu,Hanping Chen
Developing green, high efficient and precursor-universal pore tailoring approach is a major issue for biomass-derived porous carbon (BPC). In this study, the unique effect of organic salt porogen (potassium acetate) was first elucidated through investigating the component and temperature-dependent structure evolution of BPC during pyrolysis-activation process. Hydrogen bonding with biomass char rather than melting would facilitate the dispersion of porogen. Potassium acetate would catalyze cracking of biopolymers (<400 ℃) into H 2 , CO 2 , CO and CH 4 etc. and lead to plentiful macropores by gas blowing. And it decomposed into potassium species that etch the char to form micropores. Differently, cellulose and hemicellulose char intermediates with abundant carbonyl incline to retain the porous structure. BPCs from cellulose and hemicellulose possess specific surface area (SSA) ~ 1700 m 2 /g with nano-passages and three-dimensional layer framework structure. While lignin-derived BPC performs equally high SSA but bulky microporous structure. Besides, carbon layer would form from acetate decomposition and deposited on the char surface thus lead to similar surface structure. This study provides a novel insight of interaction between biomass char intermediate and organic salt porogen, which may demonstrate a precursor-universal and high efficient approach for BPC preparation.
研究领域:
材料科学
·
化学工程
·
生物质能
✓ 已验证
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2022
·
IF 9.965
Chang Liu,Hongjie Zheng,Yuwei Wang,Nan Xiao,Kai Yu,Hui Li,Xu Zhang,Hongcun Bai,Tianyi Ma,Jieshan Qiu
Soft carbon has been regarded as one of the most promising anode materials for potassium-ion batteries. However, the rearrangement of planar aromatics at high carbonization temperature usually yields a highly graphitized structure, which generally leads to inferior rate and cycle performance. In addition, the role of intrinsic carbon defects on potassium storage has not been well reported yet. In this work, crosslinked pitch-based soft carbon nanosheets have been synthesized through the iodination/dehydroiodination process at low temperature and carbonization with NaCl template. The iodine-treatment efficiently crosslinks the planar aromatics to three-dimensional framework by alkyl-bridged linkages, and reduces the strong π-π interaction during carbonization. This unique microstructure yields an ordered-in-disordered carbon microstructure, enlarged interlayer spacing, and abundant intrinsic defect sites. Benefited from these merits, the optimal sample displays 140% increase of reversible capacity to the pristine pitch-based carbon at 5 A g −1 . Particularly, it also presents 87.4% capacity retention after 1000 cycles at 1 A g −1 . This facile but simple strategy is expected to expand to other high-performance carbon materials and further understand the effect of intrinsic defects for potassium storage and beyond.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
PubMed
高影响因子
Journal of Physical Chemistry C
·
2013
·
IF 4.814
Yongfeng Liu,Chao Li,Bo Li,Mingxia Gao,Hongge Pan
The hydrogen storage properties and mechanisms of the Mg(NH2)2–2LiH system with potassium halides (KF, KCl, KBr, and KI) were investigated and discussed. The results show that the KF-added sample exhibits superior hydrogen storage properties as ∼5.0 wt % of hydrogen can be reversibly stored in the 0.08KF-added sample via a two-stage reaction with an onset dehydrogenation temperature of 80 °C. However, hydrogen storage behaviors of the samples with KCl, KBr, and KI remain almost unchanged. The fact that KF can readily react with LiH to convert to KH and LiF due to the favorable thermodynamics during ball milling should be the primary reason for its significant effects, as the presence of KH provides a synergetic thermodynamic and kinetic destabilization in the hydrogen storage reaction of the Mg(NH2)2–2LiH system by declining the activation energy of the first-step dehydrogenation as a catalyst and reducing the desorption enthalpy change of the second step as a reactant. The understanding on the role played by KF sheds light on how to further decrease the operating temperature and enhance the hydrogen storage kinetics of the metal–N–H system.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2018
·
IF 6.735
Junyu Fan,Zhaoxia Ding,Zhiwei Zhao,Jie Liu
In this study, potassium ferrate(VI) was employed for the degradation of p-arsanilic acid (p-ASA) and simultaneous removal of the generated arsenic species though in-situ coagulation. The effects of several factors, including ferrate(VI) dosage, initial pH, coexisting anions, and humic acid, on the p-ASA degradation and arsenic species removal were investigated. Under various water quality conditions, an excellent removal of p-ASA could always be achieved with the 20:1 mol radio dosage of ferrate(VI) and p-ASA within 30 min. But the removal of arsenic species is significantly affected by the water quality. It could be inhibited by alkalinity and presence of phosphate and humic acid. The generated ferric oxide was mainly 2-line ferrihydrite according to the XRD and XPS analysis. Based on the HPLC-HG-AFS and GC–MS analysis, the major degradation products were detected and the mechanism of the p-ASA degradation by ferrate(VI) and the released arsenic removal by 2-line ferrihydrite generated from ferrate(VI) was given. Two simultaneous degradation pathways of p-ASA were proposed. The p-ASA in solution attacked by ferrate(VI) in solution would lead cleavage of the As–C bond firstly to generate As(III) and p-aminophenol. On the other hand, small amounts of p-ASA initially absorbed on 2-line ferrihydrite would be firstly converted to 4-nitrophenylarsonic acid through the oxidation of –NH 2 to –NO 2 by ferrate(VI), subsequently transformed to As(III) and p-nitrophenol. Combined with the strong oxidizing and the high removal capacity of released arsenic by its generated product, ferrate(VI) have well potential applications for controlling the risk of p-ASA in wastewater.
研究领域:
环境科学
·
化学
✓ 已验证
DOI
高影响因子
Desalination and Water Treatment
·
2016
·
IF 1.272
Xiao-ling Shao,Cheng-fei Zou,Fu-xing Wang,Yang Xiong,Xiang-yang Wu
The kinetics of the oxidation of chlorophenols (CPs) by potassium permanganate was studied in the present study, along with the changes in oxidant dosage, pH, temperature, and real water matrices. The reactions between permanganate and three kinds of CPs, i.e. 4-chlorophenol (4-MCP), 2,4-dichlorophenol (2,4-DCP), and 2,4,6-trichlorophenol (2,4,6-TCP), are second order overall and first-order with respect to each reactant. The degradation rates of the CPs increase with increasing permanganate dosage or temperature. pH plays an important role during permanganate oxidation. With the increase in pH from 4.0 to 10.0, the reaction rates of 4-MCP and 2,4-DCP decrease first and then increase, and finally decrease rapidly when pH > pKa, while the rates of 2,4,6-TCP decrease continuously. The degradation rates of the CPs are obviously higher in real water than in pure water. The reaction rate follows the order of 2,4,6-TCP > 2,4-DCP > 4-MCP under acidic conditions, and follows the reverse order under alkaline conditions in both pure water and real water.
研究领域:
环境科学
·
化学
✓ 已验证
DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2018
·Vol. 28
·期 29
·1801989
·
IF 13.325
Lei Liu,Yu Chen,Yihao Xie,Peng Tao,Qinyi Li,Chenglin Yan
Carbon-based materials are considered to be one of the most promising materials for negative electrodes of the future, because of their good chemical stability, high electrical conductivity, and environmental benignity. However, to date, the underlying principles of K-ion storage in carbonaceous anodes remain elusive, which greatly hinders the development of such a category of anodes. Herein, the ultrastable K-ion storage of carbonaceous anode through systematic analyses, including comprehensive electrochemical characterizations, kinetics calculations, and structural/compositional evolution mechanism studies, is theoretically elucidated and experimentally verified. Specifically, it is found that the uniquely envelope-like nitrogen-doped carbon nanosheets with high pseudocapacitive could bring ultrastable storage of potassium ions, delivering a high initial reversible capacity of 367 mAh g −1 at a current density of 50 mA g −1 and retain 70.5 and 75.6% at current densities of 500 and 1000 mA g −1 after 1000th cycle, respectively. This study could enlighten researchers on further progress in the field of carbonaceous K-ion battery negative electrode with a long cycle life.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2022
·
IF 5.723
Shipei He,Sheng Fan,Kai Yuan,Shujia Guo,Sen Wang,Zhangfeng Qin,Mei Dong,Weibin Fan,Jianguo Wang
Herein, K + was added in the synthesis gel to regulate the distribution of acid sites in the ITQ-13 zeolite and enhance its catalytic performance in the conversion of methanol to olefins (MTO). The results indicate that a proper content of K + ions in the synthesis gel can not only expedite the crystallization of ITQ-13 zeolite, but also significantly decrease the proportion of paired Al and distribute more Al atoms in the 10-ring sinusoidal channel out from the intersection cavity. Accordingly, over the H-ITQ-13(0.3 K) zeolite prepared using the synthesis gel with a KCl/Al 2 O 3 molar ratio of 0.3, the alkene cycle of MTO keeping to the dual cycle hydrocarbon pool (HCP) mechanism is preferably enhanced, whereas the hydride transfer and aromatization reactions are substantially suppressed. As a result, H-ITQ-13(0.3 K) exhibits much longer catalytic lifetime and higher selectivity to propene and butene , in comparison with the H-ITQ-13 counterpart obtained without adding K + .
研究领域:
化学工程
·
催化材料科学
✓ 已验证
DOI
高影响因子
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2012
·
IF 2.098
Lun Wang,Fei Yuan,Hong-Qi Chen,Bo Ling,Juan Xu
A novel flow injection nanocrystals (NCs) chemiluminescence (CL) analysis method has been established for the determination of estradiol, estriol and estrone based on the enhancement of CdTe NCs–KMnO 4 CL reaction catalyzed by sodium hexametaphosphate. Glutathione (GSH)-capped CdTe nanocrystals were synthesized in aqueous medium, and the CdTe NCs emitted at around 555 nm was selected as the light emitter in CdTe NCs–KMnO 4 chemiluminescence (CL) system. It has been found that sodium hexametaphosphate (SHMP) enhanced the CL of the CdTe NCs–KMnO 4 system and estrogens increased these CL signals again in near neutral solution. UV–visible spectra, photoluminescence (PL) spectra, transmission electron microscopy (TEM) and CL spectra were used to characterize CdTe nanoparticles and investigate the mechanism of the CL reaction. On the basis of the enhancement, a novel flow-injection CL method has been established for the determination of estrogens. Under the optimum experimental conditions, three linear relationships were obtained. The method described is simple, sensitive, and has been successfully utilized for the determination of estrogens in tap water samples.
研究领域:
分析化学
·
环境科学
·
生物医学
✓ 已验证
DOI
高影响因子
MONATSHEFTE FUR CHEMIE
·
2015
·Vol. 146
·期 8
·1343-1347
·
IF 1.222
Qiu Dezhi,Wang Yanyan,Lu Dongming,Zhou Lihong,Zeng Qingle
Abstract We have developed a KOH-promoted transition-metal-free synthesis of 2-substituted 4(3 H )-quinazolinones from anthranilamides and benzyl alcohols or cinnamyl alcohol with air as oxidant. The protocol is simple, practical, and cost saving. Graphical abstract
研究领域:
有机化学
·
药物化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）