CATALYSIS LETTERS
·
2022
·Vol. 153
·期 4
·1180-1192
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IF 2.936
Xing Xiangying,Wang Huixiang,Shi Jing,Li Penghui,Ren Jingzhao,Wang Liancheng,Zhang Jianli,Liu Zhong,Lv Baoliang
WO x has good performance in olefin epoxidation, however, the presence of a large amount of Brönsted acid on WO x affects the selectivity of epoxy products. In this paper, broken carbon spheres ( b-C spheres) treated with nitric acid were used as support to anchor WO x in dynamic solvothermal process. Based on GC–MS and GC-IR detection, the obtained WO x /C greatly increased selectivity of 1,2-epoxyhexane from 16.0% ( pure WO x ) to 92.1% in epoxidation of 1-hexene. The improvement of WO x performance is attributed to the reduction of Brönsted acid sites and electron cloud density after loading, which may all result from interaction between WO x and oxygen-containing functional groups of b-C spheres. Above changes not only effectively inhibit the hydrolysis of 1,2-epoxyhexane, but also are conducive to nucleophilic reaction of H 2 O 2 to WO x, which is beneficial to the activation of H 2 O 2 . Finally, an epoxidation mechanism with oxygen vacancies as the main route under WO x /C catalysis is reasonably proposed. Graphical Abstract
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APPLIED SURFACE SCIENCE
·
2022
·
IF 7.392
Jing Feng,Gang Lang,Tingting Li,Jing Zhang,Jun Zhao,Wei Li,Weiqing Yang,Zhenju Jiang
Coordination-driven self-assembly has emerged as a smart strategy to prepare advanced materials for various applications. Here we coat Ni(II)-tannic acid complexes on the lab-made C-Cr 2 O 3 nanoparticles by this strategy, and demonstrate that this novel coating dramatically accelerate the charge transfer and thus enhance the amperometric responses for electrochemical detection of glucose and hydrazine. The charge-transfer rate ( k s ) of the obtained C-Cr 2 O 3 @Ni-MPN is much higher than that of C-Cr 2 O 3 substrate, evaluated as 1.00 and 0.82 s −1 respectively. The physicochemical and electrochemical characterizations demonstrate that the enhanced k s of C-Cr 2 O 3 @Ni-MPN is attributed to the electronegativity and the network structure of its surface. Correspondingly, C-Cr 2 O 3 @Ni-MPN exhibits superior sensitivity (5043.3 μA mM −1 cm −2 ) and ultra-low detection limit (0.02 μM) for the glucose detection, as well as high sensitivity (918.5 μA mM −1 cm −2 ) and ultra-low detection limit (0.04 μM) for the hydrazine detection. Furthermore, C-Cr 2 O 3 @Ni-MPN exhibits the excellent selectivity, stability and reproducibility, and the powerful reliability for analyzing the plasma samples. This study constructs an appropriate hierarchical structure towards catalyzing the electrochemical oxidation of targets, which achieves the amplification of the respond current and thus an ultra-sensitive electrochemical detection for the targets.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2022
·
IF 9.965
Haodong Li,Haoyu Li,Zhiwei Yang,Yizhu Lai,Qing Yang,Pengxin Duan,Zhuo Zheng,Yang Liu,Yan Sun,Benhe Zhong,Zhenguo Wu,Xiaodong Guo
The application value of silicon-based anodes has not been fully realized due to the ∼ 300% volume expansion and poor electronic conductivity. In present study, mesoporous Si/C (MP-Si/C) composite with nanosized primary particles of 30–50 nm and pore diameter of 20–40 nm was proposed, which displays superior Li storage properties. Firstly, Polyacrylic acid (PAA) was applied to fulfill in-situ carbon coating and inhibit the particle growth of SiO 2 generated from tetraethyl orthosilicate (TEOS) in stöber reaction. Secondly, Mg gas was introduced to create nano-sized Si with meso -pores and three-dimensional carbon network via the gas-cutting effect. The cycling stability and rate capability were both significantly enhanced with capacity of 671 mAh/g after 400 cycles and 593 mAh/g after 500 cycles at 2 A/g and 4 A/g, respectively, which was highly relevant to the selection of carbon source PAA and its corresponding carbon coating and Mg reduction effect. Moreover, this method bypasses the use of costly nano-silicon, which provides inspiration for the commercialization of silicon-based anodes.
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高影响因子
DALTON TRANSACTIONS
·
2022
·Vol. 51
·期 31
·11909-11915
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IF 4.569
Siyu Chen,Yanan Xu,Hongbin Du
SiOx is one of the most promising anode materials for lithium-ion batteries (LIBs), due to its high theoretical capacity and low cost. However, the huge volume expansion and low electron/ion diffusion rate hinder its further commercial applications. Herein, a simple molecular polymerization method is developed to synthesize N,P co-doped SiOx–C composites (denoted as SiOx–C@CNT), in which SiOx and carbon are uniformly dispersed at the atomic level, and the embedded carbon nanotubes improve the lithium ion diffusion kinetics. Benefiting from the unique structure, the SiOx–C@CNT composites exhibit a high reversible capacity of 848 mA h g−1 at 0.1 A g−1 and long cycling stability (84.0% capacity retention after 1500 cycles). More impressively, the LiCoO2∥SiOx–C@CNT full battery also exhibits stable cycle life (only 4.7% capacity loss after 300 cycles at 1 C). These results show the application potential of the SiOx–C@CNT anode in LIBs.
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CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Meng Wang,Panpan Zhou,Tong Feng,Zhi Song,Qingguo Ren,Huidong Gu,Xueqing Shi,Qitu Zhang,Lixi Wang
Benefiting from its large specific surface area, abundant defects and functional groups, two-dimensional (2D) laminated Ti 3 C 2 T x MXene is a kind of electromagnetic wave (EMW) absorber with great potential. However, the impedance mismatch caused by the excessive conductivity, inappropriate permittivity and lack of magnetic loss seriously hinders the application of MXene to EMW absorption. Herein, multidimensional hierarchical Ni/TiO 2 /C nanocomposites composed of three-dimensional (3D) hydrangea-like Ni/C microspheres and well-arranged 2D carbon sheets embedded with TiO 2 nanoparticles were successfully fabricated from a Ni-based trimellitic acid framework (Ni-BTC) and Ti 3 C 2 T x MXene via facile in-situ solvothermal assembly and annealing processes. As expected, excellent EMW absorption properties were obtained only by changing the annealing temperature. The minimum reflection loss ( RL min ) value of -45.6 dB and the effective absorption bandwidth (EAB) of 3.40 GHz (14.6–18.0 GHz) with a layer thickness of only 1.5 mm is obtained by annealing the sample at 700 °C. The outstanding ternary multilayer structure and the optimization of magnetoelectric synergy in impedance matching jointly create its remarkable EMW absorption performance. This work is expected to provide a simple and effective method to design MXene-based EMW absorbing materials possessing high absorption intensity, light weight, wide EAB and thin thickness.
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NEW JOURNAL OF CHEMISTRY
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2022
·Vol. 46
·期 21
·10191-10200
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IF 3.925
Fang-Di Wu,Jyh-Cherng Chen,Zi-Tao Yang
A C/Ho co-doped TiO2 catalyst was prepared by the precipitation–calcination method using Ti3C2Tx as the precursor and carbon source. X-ray diffractometry, transmission electron microscopy, X-ray photoelectron spectroscopy, N2 adsorption–desorption isotherms, UV-Vis diffuse reflectance spectroscopy, photoluminescence spectroscopy, and photoelectrochemical measurements were used for characterization. The C doped anatase TiO2 prepared by calcining Ti3C2Tx maintained the two-dimensional lamellar structure of the Ti3C2Tx precursor, and the carbon dopant was present on the surface of TiO2 in the form of C–O and CO, whereas Ho3+ was mainly doped into the lattice of TiO2, forming Ho–O bonds with oxygen instead of Ti4+. The band gap of the C/Ho co-doped TiO2 photocatalyst was reduced as compared to that of pristine TiO2, which can improve the utilization efficiency of visible light. When the doping ratio of Ho was 5% (CHT-0.05), the photocatalyst had the highest photocurrent and degradation efficiency of tetracycline hydrochloride (86.4%). The reaction mechanism for the photocatalytic degradation of TCH by the C/Ho co-doped TiO2 photocatalyst was investigated and showed that superoxide radicals (˙O2−) and holes (h+) were the main species that influenced the results. The prepared photocatalyst had good catalytic performance over four cycles, and it was stable and suitable for wastewater treatment.
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CARBON
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2022
·
IF 11.307
Xue Zhang,Xuelei Tian,Chang Liu,Jing Qiao,Wei Liu,Jiurong Liu,Zhihui Zeng
Metal-organic frameworks (MOFs) have attracted more and more attentions for preparing electromagnetic wave (EMW) absorption materials because of the porous structure , high specific surface area, and designable configuration. Herein, a series of MOF-74 derived nanocomposites were synthesized by hydrothermal process and subsequent carbonization . The EMW absorption performance and the functions of each component were investigated in depth. Moreover, the inherent EMW absorption mechanisms were comprehensively revealed. Benefiting from the synergistic effect of constituents and microstructure, the MnCo-MOF-74 derived MnO/Co/C nanocomposites delivered a minimum reflection loss value of −68.89 dB at the thickness of 2.64 mm and an effective absorption band of 5.3 GHz at the thickness of 2.3 mm. The high EMW absorption performance was ascribed to the optimized impedance matching and multiple attenuation mechanisms including interfacial and dipole polarization loss, magnetic loss, conductive loss, and multiple scatterings capability. This study shed light on exploring high-efficiency MOF-based EMW absorption materials with rational design of components and structure.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2022
·
IF 9.965
Jiafeng Gao,Songlin Zuo,He Liu,Qiwen Jiang,Chenhao Wang,Huanhuan Yin,Ziqi Wang,Jie Wang
Silicon (Si) anode is the most promising alternative for next generation lithium-ion batteries (LIBs) owing to large theoretical capacity, low working voltage and abundant natural resources. However, tremendous volume change of Si during the (de)lithiation processes causes repetitive formation of solid electrolyte interphase (SEI) layers, loss of electrical contact and electrodes pulverization , limiting its commercial application. Herein, we fabricate an interconnected hollow Si-C nanospheres/graphite composite via a facile and scalable approach. Notably, hollow Si-C nanospheres and graphite are homogeneously combined by using the surfactants as surface modifiers of graphite and introducing carbon dioxide (CO 2 ) into magnesiothermic reduction reaction, resulting in the enhanced compatibility between hollow Si-C nanospheres and graphite, and the well-established electrical conductive network. The resultant Si-C nanospheres/graphite composite anode with carbon content of 59 wt% delivers a large reversible specific capacity of 662 mAh g −1 and a high capacity retention of 65.7% at 0.5 A g −1 after 200 cycles. Such excellent rate performance and superior cycling performance are attributed to high electrical conductivity and buffering effect of graphite, superior compatibility between hollow Si-C spheres and graphite, uniform distribution of both Si-C nanospheres with a unique hollow architecture and graphite flakes inside the composites and well-established interconnected electrical conductive carbon networks, which can effectively alleviate Si volume expansion and maintain good electrical contact during cycling. This strategy provides insights into designing Si-based anodes for practical LIBs.
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高影响因子
Chemistry-An Asian Journal
·
2022
·Vol. 17
·期 11
·e202200202
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IF 4.839
Yang Ling,Yuan Gao,Yan Peng,Shiyou Guan
Graphical Herein, we fabricated a novel porous SiOx/C nanohybrids , in which carbon and SiOx not only exhibited uniform distribution at the nanoscale, the stability of SiOx/C network can also be easily adjusted via controlling the hydrolysis and condensation rate of precursors in situ. Benefiting from the unique network structure and excellent structural stability, the SiOx/C(50) shows excellent electrochemical performance in LIBs. Silicon oxides (SiOx, 0
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JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
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2022
·
IF 10.319
Runrun Cheng,Yan Wang,Xiaochuang Di,Zhao Lu,Ping Wang,Xinming Wu
At present, the problem of electromagnetic wave (EMW) pollution is critical, and the design of high-performance absorbers is of great significance. Based on the synergy between dielectric and magnetic losses, and between multicomponents in heterostructures, the development of light-weight absorbers with a strong absorption capability and multiple scattering is a promising strategy to achieve high-performance absorbers. In this work, CoFe-MOF precursors with a bouquet-like structure were prepared via the hydrothermal method, and Co 7 Fe 3 /C and Co 9 S 8 /Fe/CoS 2 /C composites were obtained through a carbonization and sulfuration treatment during the high-temperature pyrolysis process, respectively. The experimental and theoretical results show that the Co 9 S 8 /FeCoS 2 /C composite has a better EMW absorption performance, and its optimal reflection loss (RL) value is -53.9 dB at a low filler loading of 20 wt.%, which is due to the S doping that enhances the interface polarization relaxation process and improves the impedance matching characteristics. Moreover, the Co 9 S 8 /FeCoS 2 /C composite can be as candidates of high-efficiency absorbers in extreme application environments.
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Reaction Chemistry & Engineering
·
2022
·Vol. 7
·期 5
·1126-1135
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IF 5.2
Shanshan Lin,Jianguo Liu,Longlong Ma
The catalytic hydrogenation of organic substrates containing plenty of unsaturated functional groups is an important step in the industrial preparation of fine chemicals and has always been a hot spot in basic catalysis research. For example, phenylethanol obtained by the preferential hydrogenation of the CO group of acetophenone is a valuable intermediate for the production of spices, flavors, and medicines. Furthermore, as the demand for 1-phenylethanol (PhE) continues to increase, the catalytic hydrogenation of acetophenone (AP) is becoming more and more important. At present, relatively few catalytic systems are used in this reaction as the hydrogenation of acetophenone is a complex multi-step reaction. Enantioselective hydrogenation on heterogeneous catalysts is remarkable due to its inherent operational and economic advantages, such as atom economy. It is one of the most ideal methods as the catalyst is easily separated and recycled. However, the traditional synthesis way in batch reactors usually takes a long time with unsatisfactory conversion which is not conducive to industrialization. Heterogeneous non-precious metal catalysts are advantageous for their implementation in flow reactor systems for industrial applications due to their ease of separation, low cost, and environmental friendliness. Herein, we report the first use of non-noble metal Ni-supported graphene-based catalysts for hydrogenation of acetophenone to phenylethanol with high efficiency in a flow reactor made of 316L stainless steel with a length of 200 mm and an inner diameter of 6 mm which can significantly improve mass and heat transfer. The conversion rate under the optimized reaction conditions can reach 99.14% with a satisfactory selectivity of 97.77% (the conversion and selectivity are in mol%). The magnetic catalyst has a compact structure, and the Ni particles coated with carbon on the surface are uniformly distributed. After 48 hours of uninterrupted continuous experiments, the conversion rate of acetophenone still reached 88.44%. The catalyst has good cyclability, and the Ni-based catalyst after the cycle still maintains high catalytic activity without obvious deactivation, and the catalyst structure remains intact and stable.
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ENERGY & FUELS
·
2022
·
IF 4.654
Xianqiang Huang,Yanan Cui,Gang Liu,Haitao Wang,Junyu Ren,Yalin Zhang,Guodong Shen,Lingling Lv,Huai-Wei Wang,Yi-Fa Chen
With the arising concern of environmental problems, the removal of polycyclic aromatic hydrocarbons or sulfides in fuel oils is an indispensable process to achieve a clean energy source. At present, direct catalytic oxidation of benzyl C–H bonds of polycyclic aromatic hydrocarbons and sulfides to corresponding carbonyl compounds is very attractive, yet their simultaneous oxidation using a single economical-friendly catalyst is not yet well established. Here, three imidazole-decorated copper polyoxomolybdate frameworks (Im-Cu-PMoFs) are successfully synthesized by tuning different imidazole derivatives. These Im-Cu-PMoFs can serve as effective heterogeneous catalysts for the one-pot oxidation of benzylic hydrocarbons and sulfides to produce carbonyl compounds. Specifically, Im-Cu-PMoFs-3 as a single component catalyst exhibits high activity and prominent selectivity (conversion up to 99% and selectivity up to 99%) in the one-pot reaction. In addition, the possible reaction pathway and active sites are supported by sufficient characterizations and DFT calculations, which reveal the synergistic effect of Mo(VI) and Cu(II) centers in the one-pot catalysis reaction. These dual function-validated frameworks hold much promise in the exploration of novel catalysts for applications like continuous catalytic or flow bed reaction.
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