Scientific Reports
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2016
·Vol. 6
·期 1
·1-10
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IF 5.228
Zhang Jia,Zhao Chao,Liu Na,Zhang Huanxi,Liu Jingjing,Fu Yong Qing,Guo Bin,Wang Zhenlong,Lei Shengbin,Hu PingAn
Single–layer and mono–component doped graphene is a crucial platform for a better understanding of the relationship between its intrinsic electronic properties and atomic bonding configurations. Large–scale doped graphene films dominated with graphitic nitrogen (GG) or pyrrolic nitrogen (PG) were synthesized on Cu foils via a free radical reaction at growth temperatures of 230–300 °C and 400–600 °C, respectively. The bonding configurations of N atoms in the graphene lattices were controlled through reaction temperature and characterized using Raman spectroscopy, X–ray photoelectron spectroscopy and scanning tunneling microscope. The GG exhibited a strong n–type doping behavior, whereas the PG showed a weak n–type doping behavior. Electron mobilities of the GG and PG were in the range of 80.1–340 cm 2 V −1 ·s −1 and 59.3–160.6 cm 2 V −1 ·s −1 , respectively. The enhanced doping effect caused by graphitic nitrogen in the GG produced an asymmetry electron–hole transport characteristic, indicating that the long–range scattering (ionized impurities) plays an important role in determining the carrier transport behavior. Analysis of temperature dependent conductance showed that the carrier transport mechanism in the GG was thermal excitation, whereas that in the PG, was a combination of thermal excitation and variable range hopping.
研究领域:
材料科学
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物理化学
✓ 已验证
DOI
PubMed
高影响因子
ACS Applied Materials & Interfaces
·
2025
·
IF 8.2
Ganlin Liu,Xiangyu Zhang,Bohan Wang,Xinyu Wang,Haichao Liu,Cheng Zhou,Bing Yang,Liang Yao,Yuguang Ma
Polythiophene and its derivatives have emerged as promising candidates for next-generation electronic applications due to their tunable conductivity and ease of synthesis via electropolymerization. Although fused-ring thiophene monomers have attracted considerable interest for the fabrication of polythiophene films with enhanced electronic properties, systematic investigations comparing their conductivities and elucidating the structural influence of fused-ring motifs remain limited. In this study, we explore the electropolymerization behavior of various fused-ring thiophene monomers and systematically evaluate their conductivities through in situ electrochemical conductance measurements. Complemented by theoretical calculations of monomer aromaticity using nucleus-independent chemical shift (NICS) and multicenter bond index (MCBI) analyses, our findings reveal that the inhomogeneous aromaticity of fused thiophene rings plays a pivotal role in determining the conductivity of the resulting polythiophene films.
研究领域:
材料科学
·
有机化学
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物理化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CATALYSIS COMMUNICATIONS
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2023
·
IF 3.7
Mengnan Li,Huiyue Xin,Tongyang Song,Chen Zhao,Peng Wu,Xiaohong Li
Pt/Co 0.5 Fe 0.5 Al 2 O 4 catalysts with the average Pt particle size of 1.6–3.4 nm were prepared and applied to the selective hydrogenation of cinnamaldehyde (CAL). Not only the TOF was promoted from 0.19 to 2.70 s −1 , but also the selectivity to cinnamyl alcohol (COL) was improved from 68% to 94%, with the increase of Pt particle size. Stronger interaction occurred between Co 0.5 Fe 0.5 Al 2 O 4 and smaller-sized Pt particles, resulting in electron-deficient Pt particles, so that C O and C C bond could be activated simultaneously. However, electron-rich Pt species existed on Pt/Co 0.5 Fe 0.5 Al 2 O 4 with larger Pt size, which is beneficial for the preferential activation of C O bond.
研究领域:
催化化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
INORGANIC CHEMISTRY
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2022
·
IF 5.436
Xin An,Wei Jiang,Jing He,Linhua Zhu,Lingchao Xu,Hongping Li,Wenshuai Zhu,Huaming Li
Modulating the electronic characteristics of catalysts plays a significant role in optimizing their catalytic activity. Herein, Mn-doped nickel molybdate (MNMO) nanorods are synthesized via replacing the partial Ni sites by the Mn element, engineering a bimetallic synergistic effect to enhance the activation of oxygen (O2). Compared with the extremely low catalytic activity of pristine nickel molybdate (NiMoO4), complete desulfurization can be achieved by MNMO under the same reaction conditions. Characterization results show that the electronic structure and surface atomic composition of pure NiMoO4 will be modulated owing to the introduction of Mn atoms, leading to the enhancement of the oxygen vacancy content and stronger O2 activation capacity. Besides, the optimized catalyst MNMO-20 also displays satisfactory cycle performance, and the sulfur removal of dibenzothiophene still maintains 96.1% after six times of recycling. The distinctive engineering strategy and simple synthesis method provide a new insight in designing and developing oxidative desulfurization catalysts with high stability and effectivity.
研究领域:
催化材料
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环境化学
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能源化学
✓ 已验证
DOI
高影响因子
JOURNAL OF CATALYSIS
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2023
·
IF 7.3
Mengya Guo,Feng Wang,Mingwei Zhang,Li Wang,Xiangwen Zhang,Guozhu Li
Encapsulation of clean metal nanoparticles (NPs) into interior of metal–organic framework (MOF) is of great importance to remarkably improve the stability and tune the catalytic performance of metal NPs. Herein, highly dispersed Pt NPs are encapsulated in UiO-66 with different functional groups on linker (UiO-66-X, X = F, H, NH 2 , OH) through enhanced electron attraction of metal precursor by MOF node and proper reduction by H 2 /Ar gas. Compared with traditional impregnation method, the encapsulation method gives well-defined Pt NPs and controllable microenvironment. Detailed characterizations reveal that functional group of the linker can effectively tune the microenvironment and electronic properties of guest Pt NPs. In situ FTIR was utilized to investigate the adsorption capability and strength of reactants on the catalysts. The electron-deficient Pt species and appropriate surface hydrophobicity match well with the reactants, which is responsible for enhanced catalytic hydrogenation activity of C C and nitro groups. The surface hydrophobicity plays a major role in promoting alkyne hydrogenation. This work is devoted to rationalize the relationship between hydrogenation performance and catalyst property of UiO-66 encapsulated Pt NPs, in terms of energy adaptability in electronic state and structure adaptability in surface chemistry. Rational design strategy of Pt-confined-in-MOF composites through molecular level regulation is provided for hydrogenation.
研究领域:
材料科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry A
·
2015
·Vol. 3
·期 43
·21805-21814
·
IF 7.443
Yangming Lin,Yansong Zhu,Bingsen Zhang,Yoong Ahm Kim,Morinobu Endo,Dang Sheng Su
Incorporating heteroatoms into onion-like carbon (OLC, average size ∼5 nm) with a fullerene-like structure and investigating its peculiar properties are fascinating challenges. Here, we present straightforward fabrication of doped OLC samples with a high concentration of boron (0.63–4.57 at%) via a high-temperature thermal diffusion method. The highest proportion of substitutional boron of the boron species reaches 29%, which far exceeds most of the reported boron-doped carbon materials. The influence of boron on the fullerene-like layers and electronic properties of OLC is systematically investigated using Raman spectroscopy with different excitation energies (1.58–3.8 eV) and ultraviolet photoelectron spectroscopy (UPS). The as-prepared boron-doped OLC samples exhibit a perfect four-electron process for the oxygen reduction reaction (ORR), which is similar to commercial Pt/C. It is worth noting that the intrinsic relationship between the electronic properties and catalytic performance of doped samples is explored based on experimental studies instead of theoretical calculations. The results indicate that the lower work function, lower valence band edge and higher density of states (DOSs) of doped OLC are crucial to improve the catalytic performance. Our work can provide valuable information on the design of doped metal-free materials and give new evidence for enhanced ORR activity associated with heteroatom doping and electronic properties.
研究领域:
材料科学
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电化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CATALYSIS
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2024
·
IF 6.5
Ting-Ting Mao,Zhen Wei,Jun Cai,Yan-Xia Chen,Juan M. Feliu,Enrique Herrero
Se-modified platinum single-crystal surfaces in the [ 01 1 ¯ ] zone have been used as model electrocatalysts for the oxygen reduction reaction (ORR). The results show that: (1) the Pt(hkl)-[n(111)×(100)] electrodes display enhanced ORR electrocatalytic activity with Se modification. (2) Se adatoms have a double effect on the ORR kinetics at model Pt electrodes: they enhance the activity on the neighboring sites and inhibit the reaction on the sites in direct contact with the Se adatoms. (3) The hydrophobicity and the altered electronic properties are probably the reasons for the enhanced electrocatalysis for ORR with Se modification. The positive shift of the potential of zero free charge of Pt(hkl)@Se electrodes compared to that of un-modified Pt(hkl) are in agreement with these interpretations. (4) At very low coverages, the promotion effect of Se modification on ORR activity at (100) sites is stronger than that at (111) sites, which is probably due to the more pronounced hydrophobicity of the former.
研究领域:
电化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
ACS Catalysis
·
2024
·
IF 11.3
Ruifeng Wang,Yusen Chen,Xin Shang,Binglian Liang,Xiong Zhang,Hongying Zhuo,Hongmin Duan,Xuning Li,Xiaofeng Yang,Xiong Su,Yanqiang Huang,Tao Zhang
Alkali metals have been extensively used as an industrial promotor with a significant impact on the iron-based Fischer–Tropsch Synthesis (FTS), while their specific roles are still ambiguous due to the difficulty in discriminating the active species, especially in a dynamic evolution under reaction conditions. In this contribution, the dependent FTS performance on alkali metal content over iron-based catalysts by precise regulation of sodium (Na) doping was scrutinized. It is found that a trace addition of Na (0.5% mass fraction) dramatically switches the hydrocarbon selectivity from alkane to alkene, giving rise to total olefin selectivity from 27 to 76%. With the help of probe experiments and operando techniques, we demonstrate that the addition of Na can hardly affect the final state of iron carbide active species, but rather changes the formation rate of iron carbide, especially at the initial reaction stage. The presence of Na plays an exclusive role in regulating the electronic properties of iron carbide and adsorption behaviors of guest molecules, thus tailoring the reaction pathway by promoting the coupling of *CH2 species while suppressing the excessive hydrogenation, which is deemed to be the intrinsic mechanism behind the high alkene selectivity. This work provides a clear-cut insight into the effect of alkali metal promotors for iron-based F–T catalytic systems as well as a theoretical basis for designing high-performance F–T catalysts.
研究领域:
化学工程
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催化科学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2025
·
IF 8.2
Haozhang Xu,Guoan Xi,Wei Chen,Yin Hu,Jun Xia,Weiguo Song,Changyan Cao,Yanhong Zeng,Dan Zhou
The development of hydrogenation catalysts with high performance and stability could decrease the byproducts and simplify the follow-up process in the industrial process. Optimizing supported catalysts through support improvement is a feasible approach to balance effectiveness and cost. In view of this, cubic perovskite NaNbO3 was modified with organosiloxane to form a heterophase junction support consisting of amorphous silica and NaNbO3 crystal. On the basis of this, the supported Ru catalyst displayed superior performance for α-pinene hydrogenation with almost complete conversion, cis-pinane selectivity, and good stability. The relationship between the structure and performance of the catalyst was systematically investigated by comprehensive experiments and multiple characterization technologies. Due to the formation of the heterophase junction, the surface hydrophobicity, specific surface area, and electron properties of the catalyst were optimized, leading to the good dispersity of the catalyst in the hydrogenation mixture and excellent adsorption and charge transfer ability, which should account for the unique performance of the catalyst, as confirmed by a series of experiments, characterizations, and DFT calculations. This work proposes an effective approach to optimize the surface structure and electronic properties of the catalysts through constructing crystallized and amorphous heterophase junction support, which is theoretically significant for the design and development of cost-effective heterogeneous hydrogenation catalysts.
研究领域:
催化化学
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材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMISTRY-A EUROPEAN JOURNAL
·
2023
·
IF 4.3
Ruosong He,Yang Wang,Meng Li,Jianxin Liu,Yongqiang Gu,Wenhang Wang,Qiang Liu,Noritatsu Tsubaki,Mingbo Wu
Graphical Core-shell structured Fe-based catalyst Na−Fe 3 O 4 @C with confinement effect delivered higher productivity of light olefins compared with the naked Na−Fe 2 O 3 counterpart. Multiple characterization and DFT calculation verified that the timely carbon chain-growth termination, as well as unique CO 2 /H 2 ratio and electronic property on the catalytic interface played vital roles in boosting light olefins synthesis. Even though Fe-based catalysts have been widely employed for CO 2 hydrogenation into hydrocarbons, oxygenates, liquid fuels, etc., the precise regulation of their physicochemical properties is needed to enhance the catalytic performance. Herein, under the guidance of the traditional concept in heterogeneous catalysis-confinement effect, a core-shell structured catalyst Na−Fe 3 O 4 @C is constructed to boost the CO 2 hydrogenation performance. Benefiting from the carbon-chain growth limitation, tailorable H 2 /CO 2 ratio on the catalytic interface, and unique electronic property that all endowed by the confinement effect, the selectivity and space-time yield of light olefins (C 2 = −C 4 = ) are as high as 47.4 % and 15.9 g mol Fe −1 h −1 , respectively, which are all notably higher than that from the shell-less counterpart. The function mechanism of the confinement effect in Fe-based catalysts are clarified in detail by multiple characterization and density functional theory (DFT). This work may offer a new prospect for the rational design of CO 2 hydrogenation catalyst.
研究领域:
催化化学
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材料科学
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能源化学
✓ 已验证
DOI
PubMed
高影响因子
CHEMISTRY OF MATERIALS
·
2022
·
IF 10.508
Jiakai Yan,Wenhao Zhang,Shining Geng,Cheng Qiu,Yanmeng Chu,Ranjun Meng,Peng Zeng,Mingzhen Liu,Zewen Xiao,Yue Hu
Organic–inorganic lead halide perovskites (OLHPs) with the general chemical formula of APbX3 have attracted wide interest for their application in the optoelectronics field within the past decade. Despite the performance breakthroughs enabled by modifying A-site cations, a fundamental understanding of the mechanistic origins is still largely neglected. Especially, the critical role of A-site cations in modulating the physicochemical properties of perovskites is challenging to reveal because the choice of A-site cations is limited by the geometrical Goldschmidt tolerance factor. Herein, we for the first time successfully incorporated two large A-site cations in the lead halide cage by relaxing the tolerance factor in a 2D Ruddlesden–Popper system, and we obtained two novel single crystals, namely, (PA)2(Gua)Pb2I7 and (PA)2(Ace)Pb2I7, where PA = n-pentylamine, Gua = guanidine, and Ace = acetamidine. The sizes of Gua (278 pm) and Ace (277 pm) are almost identical and thus enable us to individually study the influence of other properties of the A-site cation on the optoelectronics properties including the polarity, electron donating abilities, etc. By combining with first-principles theoretical perspectives, we deliver insights into the electronic and structural features of perovskites associated with A-site electron donating properties. This adds more versatility to the roles of the A site cations in OLHPs.
研究领域:
材料科学
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物理化学
✓ 已验证
DOI
高影响因子
OPTICAL MATERIALS
·
2021
·
IF 3.08
Yunpeng Wang,Ruiting Hao,Jie Guo,Xiaoming Li,Shuiliu Fang,Huimin Liu,Shuaihui Sun
In this paper, magnesium was successfully introduced into CZTS using the DMF-based solution method, and CZMTS solar cell was prepared. The effects of Mg doping on the morphology, crystal structure, and electronic properties of the CZTS absorber were investigated in detail. The crystal structure of the CZMTS absorber and the chemical valence states of the other elements (Cu, Zn, Sn, and S) were not changed as shown by XRD , Raman, and XPS analyses. The results show that Mg doping can improve the electronic properties and microstructure of CZTS absorbers, thus enhancing the PCE from 2.91% to 4.10%. This performance enhancement is associated with good crystal quality, reduced cation-disordering defects, and high external quantum efficiency at the longwave region caused less recombination and open circuit voltage loss. Therefore, Mg doping has a positive effect on improving the performance of CZTS solar cells.
研究领域:
材料科学
·
能源科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）