Reaction Kinetics Mechanisms and Catalysis
·
2021
·Vol. 132
·期 1
·301-315
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IF 2.081
Hu Yi-Ming,Zheng Wan-Bin,Jia Ai-Ping,Luo Meng-Fei,Tang Cen,Lu Ji-Qing
A series of Ir/BN catalysts with same Ir contents (2 wt%) were calcined at different temperatures and tested for gas phase selective hydrogenation of crotonaldehyde. It was found that the thermal treatment exerted significant impacts on the structural and electronic properties of the 2Ir/BN catalysts. The catalyst calcined at 500 °C (2Ir/BN-5) showed the best performance, with a steady state of conversion of ca. 21% and a crotyl alcohol selectivity of ca. 83% at reaction temperature of 80 °C. Kinetic analysis indicated that the enhanced activity on the 2Ir/BN-5 catalyst was related to its higher surface coverage of crotonaldehyde because of the presence of small Ir particles (with a mean diameter of 3.4 nm) compared to those in the catalyst calcined at 600 °C (2Ir/BN-6, with a mean diameter of 4.4 nm). Also, the surface of the Ir species in the 2Ir/BN-5 catalyst are more electron-enriched compared to that in the 2Ir/BN-6, which suppressed the adsorption of C=C bond and thus improves the selectivity to CROL.
研究领域:
催化
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化学工程
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物理化学
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DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2021
·
IF 6.707
Wei Li,Fei Wang,Xiao-shan Chu,Xiao-yun Liu,Yan-yan Dang
Water splitting by photocatalysis technique is regarded as an eco-friendly hydrogen production strategy. However, the poor photoresponsivity and automatic electron-hole recombination greatly restrict the HER performance of conventional semiconductor photocatalyst. Here, to utilize the stable electrochemical property of hexagonal phase boron nitride (h-BN) and improve its defect of wide bandgap ( E g ≈ 4.2 eV), reduced graphene oxide (rGO) was applied to construct three-dimensional (3D) porous h-BN/rGO hybrid accompanied by a carbon-doping strategy without template assistance, then a carbon-doped 3D porous h-BN/rGO (C-BNRG) hybrid with large BET surface area was successfully prepared. As the synergistic effect of h-BN/rGO heterointerface and carbon-doping, the improved photoresponsivity and electrochemical property were presented, and the resultant 3D porous C 0.4 -BNRG hybrid presented not only greatly enhanced HER activity (157.63 μmol·g −1 ·h −1 ) but excellent durability in pH = 8.5, which was prominently higher than pristine h-BN (～36.7 times), C-BN (～12.1 times) and 3D porous BNRG hybrid (～7.0 times). This study offers a template-free approach to develop non-metallic based 3D porous hybrid for outstanding HER performance.
研究领域:
材料科学
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能源化学
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光电催化
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DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2017
·
IF 9.446
Shanshan Ding,Danjun Mao,Shaogui Yang,Fei Wang,Lingjun Meng,Mengshu Han,Huan He,Cheng Sun,Bin Xu
The novel boron nitride coupled Bi-rich Bi 4 O 5 Br 2 layered microspheres (h-BN/Bi 4 O 5 Br 2 -LMs) were successfully synthesized via a facile ionic liquid-in-water (IL/W) microemulsion-mediated route. The physical, chemical and optical properties of these heterojunction photocatalysts were thoroughly characterized with X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectrometry (EDS), transmission electron microscopy (TEM) and UV–vis diffuse reflection spectroscopy (DRS). Their photocatalytic activities were primarily evaluated by degradation of 4- tert -butylphenol (PTBP), which found 1.0 wt% h-BN/Bi 4 O 5 Br 2 -LMs to be the best one. The photocurrent experiments showed that the photocurrent density of 1.0 wt% h-BN/Bi 4 O 5 Br 2 -LMs was four times higher than that of pure Bi 4 O 5 Br 2 -LMs due to enhanced charge transfer ability of the former. It revealed that the addition of h-BN was in favor of suppressing the photoinduced electron-hole pair recombination of Bi 4 O 5 Br 2 -LMs, so as to improve the photocatalytic activity of the composite. O 2 − and h + were proved to be the main reactive species in the photocatalytic process by scavenger experiments and electron paramagnetic resonance (EPR) spectra. In addition, the photocatalytic mechanism of h-BN/Bi 4 O 5 Br 2 -LMs was further elaborated in this work. The probable degradation products were identified by GC–MS. The proposed conjugated addition and oxidation reactions were described to be the main pathways by combining the frontier electron density calculation and GC–MS results.
研究领域:
材料科学
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环境科学
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化学工程
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DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2024
·
IF 6.3
Huayi Cai,Hui Zhang,Nan Gao,Yi Fang,Xinjian Xie,Yulong Fang,Guifeng Chen
Exploring green methods for removing organic pollutants from water bodies has attracted significant attention. In this research, N-ZnO/p-BN adsorption-photocatalytic composites were prepared by a simple solvothermal method, and various analytical characterizations confirmed the formation of B-O-Zn bonds at the heterojunction interface that facilitated the separation of photogenerated carriers and revealed a type-II mechanism of charge transfer in the heterostructure. The photodegradation efficiency for oxytetracycline (OTC) by composites with different N-ZnO loadings was investigated under simulated sunlight, and the degradation efficiency of the optimal sample (50 wt% N-ZnO/p-BN) for 50 mg/L OTC reached 92.2 % at 120 min. Efficient pollutant enrichment, broadened light absorption range, high dispersion of the photocatalysts, and effective charge migration are all important factors for improving photocatalytic activity. Furthermore, the photocatalytic process was further investigated, experiments showed that the N-ZnO/p-BN composites were universally applicable under a variety of conditions and possessed the characteristics of low dosage and high degradable concentration. Finally, a rational photocatalytic mechanism was proposed for the degradation system and the degradation pathways of the main degradation model OTC were analyzed and deduced. Therefore, this study provides new ideas for designing high-performance adsorption-photocatalytic composites.
研究领域:
环境科学
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材料科学
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产品关联
DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
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2024
·
IF 5.3
Qihui Ding,Qian Shan,Qi Zhang,Mengda Chen,Ding Cai,Wei Wu
Hexagonal boron nitride (h-BN) with a large specific surface area and unique optoelectronic properties has good application prospects in many fields. The liquid phase exfoliation method is considered the most promising method for achieving controllable preparation of boron nitride nanosheets (BNNSs), but the low-cost, relatively environmentally friendly and efficient liquid phase exfoliation is still difficult to achieve. Choosing a suitable solvent system is the key to achieving efficient exfoliation. Deep eutectic solvents (DESs) have the advantages of simple synthesis, low cost, high thermal and chemical stability and strong biocompatibility and are expected to be green solvents for preparation of BNNSs . In this paper, it was found that the properties of DESs and its interaction with h-BN had a significant impact on the electrochemical exfoliation of h-BN. The intercalation effect of DES and the compatibility between DES and h-BN were the main factors affecting the yield, while the quality of BNNSs mainly depended on the decomposition and expansion effect of DES. This rule also can be applied to prepare highly conductive and hydrophilic two-dimensional material Ti-MXene. This research explores the structure–activity relationship between two-dimensional materials and DESs, and provides a theoretical basis for the environmentally friendly and efficient preparation of two-dimensional materials using DESs as exfoliation solvents.
研究领域:
材料科学
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化学工程
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纳米技术
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DOI
高影响因子
CHEMISTRY-A EUROPEAN JOURNAL
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2024
·
IF 3.9
Meiyan Liu,Chenglong Li,Guanming Liao,Fenggui Zhao,Chunxia Yao,Nan Wang,Xiaodong Yin
Graphical Two 1,4-azaborinine [6]helicenes, H[6]BN1 and H[6]BN2 , exhibit blue fluorescence with narrow FWHMs below 31 nm and high PLQY up to 92 %. Desirable circularly polarized luminescence with g lum reaching 4~5×10 −4 and good configurational stability are relized for H[6]BN1 and H[6]BN2 . Mechanochromism occurs between H[6]BN1 ′s crystalline and amorphous states by modulationg π-π intermolecular interanctions. An turquoise OLED based H[6]BN1 is manufactured with the external quantum efficiency (EQE) of 3.18 %. Boron-doped helicenes, known for their unique electronic and photophysical properties, are of great interest for numerous applications. This research introduces two new azabora[6]helicenes, H[6]BN1 and H[6]BN2 , synthesized through an efficient method. These molecules have boron and nitrogen atoms in opposing positions, enhancing their distinctive attributes. Both helicenes show excellent emission properties, with H[6]BN1 and H[6]BN2 exhibiting narrowband blue fluorescence and circularly polarized luminescence (CPL), achieving g lum values of 4~5×10 −4 which is beneficial for chiroptical applications. The addition of a donor group, 3, 6-di-tert-butyl-9H-carbazole, in H[6]BN2 improves luminescence, likely due to enhanced molecular orbital overlap and electron delocalization. H[6]BN1 ′s needle-like single crystals exhibit mechanochromism, changing luminescent color from yellow to green under mechanical stress, which is promising for stimulus-responsive materials. In conclusion, this study presents a novel class of BN[6]helicenes with superior chiroptical properties. Their combination of electronic features and mechanochromism makes them ideal for advanced chiroptical materials, expanding the potential of helicene-based compounds and offering new directions for the synthesis of molecules with specific chiroptical characteristics.
研究领域:
有机光电材料
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光学材料科学
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产品关联
DOI
PubMed
高影响因子
RSC Advances
·
2019
·Vol. 9
·期 25
·14286-14295
·
IF 3.049
Wenhui He,Yawen Wang,Caimei Fan,Yunfang Wang,Xiaochao Zhang,Jianxin Liu,Rui Li
The introduction of oxygen vacancies (OVs) on the surface of photocatalysts has already been proven to be an effective way to extend the light response to visible light and trap charge carriers, thereby promoting the photocatalytic performance. In this study, h-BN/OV-BiOCl composites were prepared using hexagonal boron nitride (h-BN) to further improve the visible-light photocatalytic activity of oxygen-vacancy-enriched bismuth oxychloride (OV-BiOCl). The composition and morphology of these materials were investigated, and the photocatalytic performance experiments showed that the introduction of h-BN could significantly improve the visible-light photocatalytic activity of OV-BiOCl, which was 1.7 and 1.4 times that of pure OV-BiOCl for the degradation of rhodamine B (RhB) and bisphenol A (BPA) when the h-BN content was 5 wt%, respectively. The role of h-BN was comprehensively investigated, and the results revealed that the presence of negatively charged h-BN could improve the separation efficiency of photoinduced electrons (e−) and holes (h+) by promoting the migration of positively charged h+ to the surface of the photocatalyst, as expected. Moreover, the oxygen vacancies in OV-BiOCl were increased in the presence of h-BN; this favored the activation of more adsorbed O2 for the oxidation of pollutants. Finally, a probable mechanism was proposed for the improved photocatalytic activity of the h-BN/OV-BiOCl composites. This study provides an insight into the roles of h-BN in oxygen-vacancy-enriched photocatalysts.
研究领域:
材料科学
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环境科学
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DOI
PubMed
高影响因子
CHEMOSPHERE
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2024
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IF 8.1
Ning Wang,Wei Wang,Dan Qi,Guodong Kang,Bo Wang,Houhu Zhang,Jiuli Ruan,Rongrong Lei,Zhenhua Zhang,Shenghu Zhang,Hao Zhou
The production of cheap, efficient, and stable photocatalysts for degrading antibiotic contaminants remains challenging. Herein, Bi 2 O 3 /boron nitride (BN)/Co 3 O 4 ternary composites were synthesized using the impregnation method. The morphological characteristics, structural features, and photochemical properties of the prepared photocatalysts were investigated via X-ray diffraction, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, high-resolution transmission electron microscopy, and ultraviolet–visible (Vis) diffuse reflectance spectrum techniques. BN was used as a charge transfer bridge in the ternary composites, which afforded a heterojunction between the two semiconductors. The formation of the heterojunction substantially enhanced the charge separation and improved the photocatalyst performance. The degradation activity of the Bi 2 O 3 /BN/Co 3 O 4 ternary composites against norfloxacin (NOR) under Vis light irradiation was investigated. The degradation rate of NOR using 5-wt% Bi 2 O 3 /BN/Co 3 O 4 reached 98% in 180 min, indicating excellent photocatalytic performance. The ternary composites also exhibited high photostability with a degradation efficiency of 88.4% after five cycles. Hydroxyl radicals (•OH), superoxide radicals (•O 2 − ), and holes (h + ) played a synergistic role in the photocatalytic reaction, where h + and •O 2 − were more important than •OH. Consequently, seven intermediates and major photocatalytic degradation pathways were identified. Toxicity experiments showed that the toxicity of the degradation solution to Chlorella pyrenoidosa decreased. Finally, the ecotoxicity of NOR and its intermediates were analyzed using the Toxicity Estimation Software Tool, with most intermediates exhibiting low toxicity.
研究领域:
环境科学
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材料科学
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生物学
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产品关联
DOI
PubMed
高影响因子
PROGRESS IN ORGANIC COATINGS
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2024
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IF 6.5
Beibei Chen,Wenquan Dong,Wenchao Shi,Xuanlin Li,Bi Yang,Yang Tong,Lin Zhang,Jianzhang Wang
Developing high-performance of organic solid lubricating coating is of great significance for extending the life of the moving systems/parts. Herein, the non-covalently modified h-BN nanosheets by graphene oxide (BNNSs/GO) were elaborately constructed to enhance the mechanical, friction and wear properties of epoxy nanocomposite coating. The microstructure feature and chemical composition of BNNSs/GO were determined by various spectroscopic techniques. The tribological performance of nanocomposite coatings were tested using ball-on-disc friction tester, and 440C stainless-steel ball with diameter of 8 mm was used as the counterface material. The GO nanosheets acted an active platform for BNNSs, which improved the dispersion of BNNSs and interface interaction with epoxy. The anchoring BNNSs could break the strong π-π, and van der Walls forces among GO nanosheets. The thickness of epoxy nanocomposite coatings was about 60 μm. And the epoxy-1.0 wt%BNNSs/GO demonstrated much higher hardness and elastic modulus than epoxy, increased by 112.62 % and 53.37 %, respectively. The coefficient of friction (COF) and wear rate of epoxy-1.0 wt%BNNSs/GO were the lowest, with a reduction of 89.7 % and 97.5 %, respectively. The synergistic lubricating mechanism of epoxy-BNNSs/GO coating was proposed, which could provide a new light on the design of high antifriction and wear resistance of organic nanocomposite coating.
研究领域:
材料科学
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表面工程
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产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
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2020
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IF 3.83
Junxiao Tang,Wei Ji,Jingjing Xie,Yunwei Shi,Yuexu Zhu,Qianglong He,Weimin Wang
In this study, B 6.5 C-TiB 2 -SiC-BN composite was fabricated via reactive hot pressing from a powder mixture of TiCN, B, and Si. The reaction process of the powder mixture was investigated by heat treatment at elevated temperatures. The as-reacted powder products possessed a core-shell structure of TiB 2 surrounded by h-BN. During densification, the h-BN in this structure acts as a diffusion channel and lubricant, which promoted the densification process. The extremely small size, fresh surface of in-situ formed phases, and uniform dispersion in synthesized powders also contributed to sintering. The designed reactive hot-pressing sintering effectively resolves the difficulty of obtaining uniformly-dispersed BN. The obtained bulk B 6.5 C-TiB 2 -SiC-BN composite ceramic shows high relative density (98.8%) and good comprehensive mechanical properties including hardness, bending strength , and fracture toughness of 19.6 GPa, 801 MPa, and 5.31 MPa m 1/2 , respectively.
研究领域:
材料科学
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陶瓷工程
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产品关联
DOI
高影响因子
ACS Applied Nano Materials
·
2024
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IF 5.3
Yuting Li,Jiaming Song,Xin Zhao,Bingda Li,Zhuo Wang,Juanjuan Yang,Guoshuai Ban,Feng Teng,Jialong Ma,Chaoying Meng,Honggang Ye,Guangde Chen,Zhonghua Dai,Yu Cong
With increasing environmental pollution, the utilization of green techniques, such as photocatalysis, is required to degrade harmful sources without secondary pollution. In this study, we synthesized an efficient photocatalyst, i.e., a h-BN/BiPO4 heterostructure modified by Ag nanoparticles at the interface (Ag/BN/BPO) by photodeposition and a hydrothermal method, and investigated photocatalytic degradation performance for rhodamine B dye (RhB). It was found that 95% of RhB was removed by Ag/BN/BPO (optimal ratio) after 60 min of light exposure. Compared to BiPO4 and BN/BiPO4, the removal efficiency was improved by 50 and 30%, respectively. The high photocatalytic degradation activity of Ag/BN/BPO could be possibly attributed to the synergistic effect of the improved separation efficiency of electron–hole pairs by the special heterostructure design and the increased adsorption capacity due to the large specific surface area of the layered h-BN. This study provided a possible route for the development of highly efficient photocatalysts for the degradation of organic pollutants.
研究领域:
环境科学
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材料科学
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产品关联
DOI
高影响因子
Polymer Chemistry
·
2016
·Vol. 7
·期 29
·4717-4727
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IF 5.687
Qingfu Ban,Jie Kong
Well-defined hyperbranched polymers with long-chain backbones between the branched points (HyperMacs) are an emerging issue in topological polymers. Owing to the difficult discrimination of branching points interfered with or overlapped by long-chain backbones in nuclear magnetic resonance signals, the fine identification and quantitative characterization of intramolecular cyclization and the calculation of the degree of branching for HyperMacs are always challenges. In this contribution, a convenient expression of the macro-cyclic index (m-CI) was presented and deduced as the ratio of NA/NB of HyperMacs to that of their completely intramolecular cyclized analogues. The physical meaning of m-CI is the similarity of HyperMacs to their completely cyclized analogues. Accordingly, a m-CI closer to 1 means a high degree of intramolecular cyclization, even complete cyclization. The experimental validation via model polymers indicates that m-CI is a facile parameter to analyze intramolecular cyclization of HyperMacs. The increase of the chain length of the backbones between branched points can enhance intramolecular cyclization of HyperMacs accompanied with the increase of the m-CI value. As an original contribution to polymer science, the presentation of m-CI overcomes the difficult problem of quantitative characterization of intramolecular cyclization in long-chain hyperbranched polymers, which is helpful for a good understanding of their relationship between topological structures and properties.
研究领域:
高分子科学
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材料科学
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化学工程
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DOI
高影响因子
危险品化学品经营许可证（带存储）