Materials Today Communications
·
2021
·
IF 3.383
Gongguo Zhang,Mengfan Li,Hongwen Huang,Yiqun Zheng
We report a facile synthesis of cubic/cuboidic gold nanocrystals with tunable surface concavity via seeded growth. The key to the success of this work lies in the use of syringe pump to change the injection rate of the metal precursor and thus manipulation over atomic deposition versus surface diffusion . The formation mechanism and the morphology-dependent plasmonic properties, as well as electrochemical behavior are analyzed.
研究领域:
材料科学
·
化学
✓ 已验证
DOI
高影响因子
ACS Applied Nano Materials
·
2021
·
IF 5.097
Xiuli Zhang,Weiyan Liu,Hailong Li,Shuixin Xia,Chia-Kuang Tsung,Hao Liu,Wei Liu,Yi Yu
Understanding the sintering kinetics of nanoparticles is important for their applications, such as printable nanoinks and wearable devices. However, it is challenging to in situ study the sintering process at nanoscale in a liquid environment. In this work, in situ investigation of the thermal sintering of gold nanoparticles is performed using liquid cell transmission electron microscopy. We have observed the unique sintering process of two nanoparticles in the liquid phase. By heating the gold nanoparticle solution in a liquid cell, a neck formed between the two nanoparticles at the initial sintering stage, followed by a rapid increase of neck size accompanied by a more rounded surface, and finally, the as-formed gold dimer shrank to a short nanorod. The sintering observations are dominated by two different surface diffusion paths and grain boundary diffusion. Furthermore, the high surface energy of small nanoparticles results in a higher shrinkage ratio in sintering. This insight of the kinetics of nanoparticle sintering provided by in situ characterization offers guidance for the future applications such as ink-jet printing.
研究领域:
材料科学
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纳米技术
✓ 已验证
DOI
高影响因子
ACS Nano
·
2021
·
IF 15.881
Fan Li,Yuan Zong,Yanling Ma,Mingxu Wang,Wen Shang,Peng Tao,Chengyi Song,Tao Deng,Hong Zhu,Jianbo Wu
To explore the ordering mechanism of facet alloy nanocrystals with randomly distributed atoms, we investigate kinetic and thermodynamic behaviors of the ordering phase transition from face-centered cubic Pt3Co nanocrystals to L12-Pt3Co intermetallic nanocrystals. It is observed that the ordering occurs from the surface and then gradually into the interior in a layer-by-layer mode, involving the competition between two kinds of phase transition modes: long-range surface diffusion-induced phase transition (SDIPT) and short-range reconstruction-induced body phase transition (RIBPT). The density functional theory calculations demonstrate that the surface status acts as a pivotal part in the thermodynamics and kinetics of the nanoscale ordering transition. With the development of the controllable heating process, both SDIPT and RIBPT modes can be manipulated as well as the morphology of the final product. This in situ work lays the foundations for potentially realizing shape-controlled intermetallic nanostructures by utilizing the thermal annealing method and makes preparations for the rational design of the surface and near-surface atomic configurations at the atomic scale.
研究领域:
材料科学
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物理化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
AICHE JOURNAL
·
2018
·Vol. 65
·期 1
·305-316
·
IF 3.326
Aiying Xue,Yan Sun
This article reports a microscopic method to directly visualize protein adsorption and transport in bare capillaries modified with ion exchange groups. Silica capillaries were coated with poly(vinyl alcohol) to eliminate nonspecific protein absorption and then functionalized with diethylaminoethyl (DEAE) and DEAE-dextran to prepare anion-exchange capillaries denoted as D-C and D-dex-C, respectively. Protein concentration profiles acquired from microscopic images were analyzed with a one-dimensional diffusion-adsorption model to determine adsorption capacities and effective diffusivities. It revealed that surface diffusion of bound protein on the capillary surface in D-Cs was negligible, but that of bound proteins markedly contributed to protein transfer in D-dex-Cs because of the chain delivery effect of charged dextran chains. The chain delivery was little affected by protein concentration, but significantly increased with ionic capacity. The research thus provided new insight into protein adsorption and transport behaviors on the surfaces modified with ion exchange groups of different structures. © 2018 American Institute of Chemical Engineers AIChE J , 65: 305–316, 2019
研究领域:
生物化学
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分析化学
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产品关联
DOI
高影响因子
Nanoscale
·
2016
·Vol. 8
·期 35
·15970-15977
·
IF 7.76
Xixi Wang,Maochang Liu,Yubin Chen,Wenlong Fu,Bin Wang,Liejin Guo
The synthesis of semiconductor nanocrystals is usually limited to high-level symmetry, as constrained by the inherent, for example, face-centered cubic or hexagonal close-packed lattices of the crystals. Herein, we report a robust approach for breaking the symmetry of the CdS lattice and obtaining high-quality CdS ultrathin monopods, bipods, tripods, and tetrapods. The success relies on manipulating reaction kinetics by dropwise addition of a precursor solution, which permits deterministic control over the number of CdS monomers in the reaction solution. With rapid monomer supply by fast precursor injection, growth was restricted to only one {111} facet of the nascent CdS tetrahedron to produce an asymmetric ultrathin monopod (a zinc-blende tip with a wurtzite arm). Otherwise, growth monomers could access adjacent {111} facets through surface diffusion and thus lead to the switch of the growth pattern from asymmetric to symmetric to generate an ultrathin multipod (a zinc-blende tip/core with multi-wurtzite arms). These symmetry-controlled photocatalysts were characterized by a fine-tuned zinc blende–wurtzite intergrowth type-II homojunction. After evaluating their structure-dependent solar-hydrogen-production properties, the CdS ultrathin monopod with an appropriate length for controllable charge transportation showed the highest photocatalytic activity.
研究领域:
材料科学
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化学工程
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纳米技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF POWER SOURCES
·
2019
·
IF 7.467
Xiaojing Zhi,Tian Gan,Nianjun Hou,Lijun Fan,Tongtong Yao,Jun Wang,Yicheng Zhao,Yongdan Li
Ni 1-x Zn x O-Ce 0.8 Sm 0.2 O 1.9 is studied as an anode material for solid oxide fuel cells with hydrogen and methanol as fuels. After reduction, Zn is incorporated into the lattice of Ni when x is less than 0.5, while NiZn alloy accompanied with ZnO is formed when x reaches 0.8. The electrochemical oxidation process of H 2 on the anode is investigated with a symmetric cell under various H 2 partial pressures. The addition of Zn increases the electron cloud density of Ni and thus weakens the adsorbing strength of H on Ni, accelerating the surface diffusion of H species, which is the rate determining step when the content of Zn is lower than 0.5. ZnO in the reduced Ni 0·2 Zn 0·8 O- Ce 0.8 Sm 0.2 O 1.9 anode facilitates H spillover, resulting in the variation of the rate determining step and the highest activity of the anode. The cell with Ni 0·2 Zn 0·8 O- Ce 0.8 Sm 0.2 O 1.9 anode shows the highest performance with both H 2 and methanol fuels at 700 °C. ZnO also improves coking resistance of NiO-Ce 0.8 Sm 0.2 O 1.9 anode.
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 ELECTROANALYTICAL CHEMISTRY
·
2021
·
IF 4.464
Ping Li,Runze Dong,Pu Yang,Xukun Ma,Fei Yan,Pan Zhang,Dong Fu
Ni 1-x Cd x O-SDC composite materials are prepared and investigated as the hydrogen electrodes for reversible solid oxide cell (RSOC). XRD, SEM, XPS and Raman techniques have been used to characterize structural properties, textural and mobility of adsorbed oxygen and lattice oxygen. After reduction, Cd is incorporated into the lattice of Ni and formed Ni Cd alloy. The reduced Ni 0.9 Cd 0.1 O-SDC possesses the most oxygen vacancies , resulting in the highest catalytic activity for the electrochemical oxidation of H 2 and the electrolysis of H 2 O. The electrochemical oxidation process of H 2 on the hydrogen electrode in solid oxide fuel cell (SOFC) mode is investigated with a symmetric cell under various H 2 partial pressures. The surface diffusion of adsorbed H atom on the reduced Ni 1-x Cd x O-SDC composite hydrogen electrodes is the rate-determining step (RDS) for H 2 electrochemical oxidation reaction and the reduced Ni 0.9 Cd 0.1 O-SDC shows the highest electrochemical oxidation rates. The maximum power densities ( P max ) of the cells with reduced Ni 0.9 Cd 0.1 O-SDC as hydrogen electrode is 796.2 mW cm −2 when using H 2 as the fuel at 700 °C. Furthermore, in solid oxide electrolysis cell (SOEC) mode, the cell with reduced Ni 0.9 Cd 0.1 O-SDC as hydrogen electrode exhibits the best electrolysis performance under various H 2 O concentrations and the current densities remain stable during the test at different voltages for a total period of 10 h under 47%H 2 O + 53%H 2 O atmosphere at 700 °C.
研究领域:
材料科学
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能源工程
✓ 已验证
产品关联
DOI
高影响因子
AICHE JOURNAL
·
2022
·Vol. 68
·期 7
·e17677
·
IF 4.167
Shen Hu,Jiaxuan Chen,Qunfeng Zhang,Junru Liu,Jinlin Meng,Guanghua Ye,Xinggui Zhou,Weikang Yuan
Surface barriers persist in the molecular transport across external crystal surface of zeolites, which brings strong influences on zeolite catalysis. This study probes the role of crystal-size–dependent surface barriers in zeolite catalysis, with n -pentane isomerization catalyzed by Pt/ZSM-5 as a model reaction system. Chemical liquid deposition of SiO 2 is performed to reduce surface barriers on ZSM-5 crystals with different sizes. After SiO 2 deposition, surface barriers on both small (266 nm) and large (1304 nm) crystals are significantly reduced, while the improvement in catalytic activity for the large crystals (76.1%–129.1%) is much higher than that for the small ones (−17.4% to 16.7%). For the large ZSM-5 crystals, diffusion limitation is stronger, and thus the effect of surface barriers on catalytic activity is more important. This study reveals the unique role of crystal-size–dependent surface barriers in zeolite catalysis, and understanding this is important for the optimal design of zeolite catalysts.
研究领域:
化学工程
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材料科学
·
催化反应
✓ 已验证
产品关联
DOI
高影响因子
Chemical Engineering and Processing-Process Intensification
·
2019
·
IF 3.031
Yongkun Zheng,Qinglian Wang,Chen Yang,Ting Qiu
Catalyst performance is highly relevant to its mass transport performance. In the present study, seven styrene-co-divinylbenzene polymer samples were synthesized by varying the amounts of crosslinker and porogen, so as to elucidate mass transport mechanism in poly (styrene-co-divinylbenzene) microspheres with hierarchical pore structure. Correspondingly, pore structure parameters of seven samples were characterized by BET and MIP. By choosing toluene as probe molecule, surface diffusion coefficient and pore diffusion coefficient of toluene inside the microspheres were measured. The experimental results indicated that both surface diffusion coefficient and pore diffusion coefficient increase with the rise of the ratio of average mesopore diameter to average macropore diameter under a certain porosity. Moreover, the rise of porosity results in greater enhancement of pore diffusion coefficient than surface diffusion coefficient. Finally, sulfonic acid groups were anchored onto polymer microspheres to investigate the relative importance of mass transport performance and catalytic performance by virtue of methyl acetate hydrolysis.
研究领域:
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Water Process Engineering
·
2024
·
IF 6.3
Fangfang Liu,Mengnan Lu,Xiao Yang,Yuedi Wang,Chunmei Wang,Xiaomin Dou
This work proposed introducing nanoscale Fe-Zr oxides onto the layered-surfaces of MXene carriers to maintain well dispersion and anchoring stabilization. The results indicated that Fe-Zr oxide/MXene has a superior adsorption capacity of 209.1 mg/g at pH 7.0. The mass transfer of antimonite onto Fe-Zr oxide/MXene was investigated by numerical solving the homogeneous surface diffusion model. The external mass transfer coefficient ( k f ) and surface diffusion coefficient ( D S ) were determined to be 6.48 × 10 −4 and 1.86 × 10 −8 cm/min, respectively, and the latter was rate-limited. The 2-D profiles of Sb(III) diffusion within the adsorbents were visualized. Data mining and knowledge discovery using machine learning models indicated that the gradient boosting regression (GBR) model successfully predicted the test datasets. The operational conditions outweigh adsorbent properties in capacity prediction, and equilibrium concentration and adsorbent dose, are the most two important features. Using the trained GBR model, the Sb(III) adsorption capacities of MXene (Ti 3 C 2 ) and Fe-Zr/MXene were well predicted. This work provides insights on understanding the mass transfer mechanisms of Sb(III) in functionalized-MXene adsorbents and employing machine learning models for tuning the treatments for better achievements.
研究领域:
环境科学
·
材料科学
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化学工程
·
数据科学
✓ 已验证
产品关联
DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2022
·Vol. 32
·期 43
·2205677
·
IF 19.924
Ziqiang Wu,Kaiwen Wang,Weiwei Sun,Zhipeng Li,Zhihong Ma,Yunfeng Zhu,Yongjin Zou,Yao Zhang
The safety issues oflithium-ion batteries provoke the development of highly secure solidelectrolytes. Hydride electrolytes owning the high electrochemical stabilityand anode compatibility may sufficiently relieve theconcerns of safety. However, the low ionic conductivity at room temperature hampersits further application. Herein, the strategy of defect-induced (BH 4 ) – deformation to achieve high ionicconductivity LiBH 4 /BN composite electrolyte is suggested. The theoreticalcalculations indicate that the volume of the (BH 4 ) – tetrahedron is expanded by 14%. Such atetrahedron deformation weakens the Li H interaction forces in LiBH 4 , and thus promotes the Li-ion migration. The LiBH 4 /BN composites are enabled to deliver lithium ionicconductivity of 1.15 × 10 –4 S cm –1 at 40 °C with a Li-ion transference number of 97%, persuading an excellent solidelectrolyte for all-solid-state batteries. The sub-surface of LiBH 4 offers the lowest migration barrier among all possiblechannels, paving the optimal way for Li-ion migration. Furthermore, the LiBH 4 /BN electrolytes supply excellent electrochemical stabilityand electrode compatibility. The utilized strategy of outfield induction (notonly defects) and ligand deformation (not only (BH 4 ) – ) may also be extended to other solid electrolytes.
研究领域:
材料科学
·
固态离子学
·
能源化学
·
电化学
·
纳米材料
·
电池技术
✓ 已验证
DOI
高影响因子
Nature Communications
·
2024
·Vol. 15
·期 1
·1-10
·
IF 14.7
Fan Yamei,Li Rongtan,Wang Beibei,Feng Xiaohui,Du Xiangze,Liu Chengxiang,Wang Fei,Liu Conghui,Dong Cui,Ning Yanxiao,Mu Rentao,Fu Qiang
Sintering of active metal species often happens during catalytic reactions, which requires redispersion in a reactive atmosphere at elevated temperatures to recover the activity. Herein, we report a simple method to redisperse sintered Cu catalysts via O 2 -H 2 O treatment at room temperature. In-situ spectroscopic characterizations reveal that H 2 O induces the formation of hydroxylated Cu species in humid O 2 , pushing surface diffusion of Cu atoms at room temperature. Further, surface OH groups formed on most hydroxylable support surfaces such as γ-Al 2 O 3 , SiO 2 , and CeO 2 in the humid atmosphere help to pull the mobile Cu species and enhance Cu redispersion. Both pushing and pulling effects of gaseous H 2 O promote the structural transformation of Cu aggregates into highly dispersed Cu species at room temperature, which exhibit enhanced activity in reverse water gas shift and preferential oxidation of carbon monoxide reactions. These findings highlight the important role of H 2 O in the dynamic structure evolution of supported metal nanocatalysts and lay the foundation for the regeneration of sintered catalysts under mild conditions.
研究领域:
催化
·
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
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