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Koutecky-Levich analysis applied to nanoparticle modified rotating disk electrodes： Electrocatalysis or misinterpretation？

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Nano Research 2014年第1期7卷 71-78页

作者： justus masa Christopher Batchelor-McAuley Wolfgang Schuhmann Richard G. Compton Department of Chemistry Physical and Theoretical Chemistry Laboratory University of Oxford South Parks Road Oxford OX13QZ UK Analytische Chemie and Center for Electrochemical Sciences-CES Ruhr-Universitat Bochum Universitatsstr 150 D-44780 Bochum Germany

The application of naive Koutecky-Levich analysis to micro- and nano-particle modified rotating disk electrodes of partially covered and non-planar geometry is critically analysed. Assuming strong overlap of the diffusion fields of the particles such that transport to the entire surface is time-independent and one-dimensional, the observed voltammetric response reflects an apparent electrochemical rate o constant koapp, equal to the true rate constant ko describing the redox reaction of interest on the surface of the nanoparticles and the ratio,ψ, of the total electroactive surface area to the geometric area of the rotating disk surface. It is demonstrated that Koutecky-Levich analysis is applicable and yields the expected plots of I-1 versus ω-1 where I is the current and ω is the rotation speed but that the values of the electrochemical rate constants inferred are thereof koapp, not ko. Thus, for ψ 〉 1 apparent electrocatalysis might be naively but wrongly inferred whereas for ψ 〈 1 the deduced electrochemical rate constant will be less than ko. Moreover, the effect of ψ on the observed rotating disk electrode voltammograms is significant, signalling the need for care in the overly simplistic application of Koutecky-Levich analysis to modified rotating electrodes, as is commonly applied for example in the analysis of possible oxygen reduction catalysts.

关键词： rotating disk electrodes nanoparticles electrocatalysis electrode kinetics electro-reduction ofoxygen Koutecky-Levich analysis

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Oxygen-deficient titania as alternative support for Pt catalysts for the oxygen reduction reaction

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Journal of Energy Chemistry 2014年第6期23卷 701-707页

作者： Anqi Zhao justus masa Wei Xia Laboratory of Industrial Chemistry Ruhr-University BochumD-44780 Bochum Germany Analytical Chemistry and Center for Electrochemical Sciences-CES Ruhr-University BochumD-44780 Bochum Germany

Insufficient electrochemical stability is a major challenge for carbon materials in oxygen reduction reaction （ORR） due to carbon corrosion and insufficient metal-support interactions. In this work, titania is explored as an alternative support for Pt catalysts. Oxygen deficient titania samples including TiO2-x and TiO2_xNy were obtained by thermal treatment of anatase TiO2 under flowing H2 and NH3, respectively. Pt nanoparticles were deposited on the titania by a modified ethylene glycol method. The samples were characterized by N2-physisorption, X-ray diffraction and X-ray photoelectron spectroscopy. The ORR activity and long-term stability of supported Pt catalysts were evaluated using linear sweep voltammetry and chronoamperometry in 0.1 mol/L HC104. Pt/TiO2_x and Pt/TiO2_xNy showed higher ORR activities than Pt/TiO2 as indicated by higher onset potentials. Oxygen deficiency in TiO2-x and TiO2-xNy contributed to the high ORR activity due to enhanced charge transfer, as disclosed by electrochemical impedance spectroscopy studies. Electrochemical stability studies revealed that Pt/TiOE_x exhibited a higher stability with a lower current decay rate than commercial Pt/C, which can be attributed to the stable oxide support and strong interaction between Pt nanoparticles and the oxygen-deficient TiO2-x support.

关键词： TiO2 oxygen-deficiency Pt catalyst oxygen reduction reaction

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Improving the performance of metal-organic frameworks for thermo-catalytic CO_(2)conversion:Strategies and perspectives

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Chinese Journal of Catalysis 2021年第11期42卷 1903-1920页

作者： Leiduan Hao Qineng Xia Qiang Zhang justus masa Zhenyu Sun State Key Laboratory of Organic-Inorganic Composites College of Chemical EngineeringBeijing University of Chemical TechnologyBeijing 100029China College of Biological Chemical Science and EngineeringJiaxing UniversityJiaxing 314001ZhejiangChina Department of Chemistry Washington State UniversityPullman 99164United States Department of Chemistry Kyambogo UniversityP.O.Box 1KyambogoKampalaUganda

Climate change caused by the increasing emission of CO_(2)to the atmosphere has become a global *** ameliorate this issue,converting CO_(2)into valuable chemicals is highly desirable,enabling a sustainable low-carbon *** this end,developing efficient catalytic systems for CO_(2)conversion has sparked intense interests from both academia and *** advantage of their highly porous structures and unique properties,metal−organic frameworks(MOFs)have shown great potential as heterogeneous catalysts for CO_(2)*** transformations involving CO_(2)have been accomplished over MOFs-based *** we provide a comprehensive and up-to-date review on recent advances of heterogeneous CO_(2)thermocatalysis using MOFs,highlighting relationships between structures and *** attention is given to the design strategies for improving the catalytic performance of *** available to enrich the catalytic active sites in MOF structures are stressed and their respective impacts on CO_(2)conversion efficiency are *** synergistic effects between each active site within the structure of MOFs and derivatives are *** the end,future perspectives and challenges in CO_(2)conversion by heterogeneous catalysis with MOFs are described.

关键词： CO_(2) conversion Metal-organic frameworks Catalytic active sites Synergy Catalytic performance

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Promoting effect of nitrogen doping on carbon nanotube-supported RuO2 applied in the electrocatalytic oxygen evolution reaction

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Journal of Energy Chemistry 2016年第2期25卷 280-286页

作者： Kunpeng Xie Wei Xia justus masa Fengkai Yang Philipp Weide Wolfgang Schuhmann Martin Muhler Laboratory of Industrial Chemistry Ruhr-University Bochum 44780 Bochum Germany Analytical Chemistry-Center for Electrochemical Sciences (CES) Ruhr-University Bochum 44780 Bochum Germany Competence Centre for Catalysis Chemical Engineering Chalmers University of Technology Gothenburg 41296 Sweden Max Planck Institute for Chemical Energy Conversion 45470 Miilheiman der Ruhr Germany

RuO2 nanoparticles supported on multi-walled carbon nanotubes（CNTs） functionalized with oxygen（OCNTs） and nitrogen（NCNTs） were employed for the oxygen evolution reaction（OER） in 0.1 M *** catalysts were synthesized by metal-organic chemical vapor deposition using ruthenium carbonyl（Ru3（CO）（12）） as Ru precursor. The obtained RuO2/OCNT and RuO2/NCNT composites were characterized using TEM, H2-TPR, XRD and XPS in order probe structure–activity correlations, particularly, the effect of the different surface functional groups on the electrochemical OER performance. The electrocatalytic activity and stability of the catalysts with mean RuO2 particle sizes of 13–14 nm was evaluated by linear sweep voltammetry, cyclic voltammetry, and chronopotentiometry, showing that the generation of nitrogen-containing functional groups on CNTs was beneficial for both OER activity and stability. In the presence of RuO2, carbon corrosion was found to be significantly less severe.

关键词： Ruthenium dioxide Chemical vapor deposition Nitrogen-doped carbon nanotubes Oxygen evolution reaction

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单原子配位结构及与载体相互作用的调控用于二氧化碳电催化还原

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物理化学学报 2022年第11期38卷 140-159页

作者：陈宇新王丽君姚志波郝磊端谭心怡 justus masa Alex W.Robertson 孙振宇北京化工大学化学工程学院有机-无机复合材料国家重点实验室北京100029 北京理工大学材料科学与工程学院北京环境科学与工程重点实验室北京100081 京博哥大学化学系乌干达坎帕拉京博哥999123 华威大学物理系英国考文垂CV47AL

电催化二氧化碳还原(ECR)制备高值化学品被认为是在碳中和背景下实现可再生能源存储及降低CO浓度的一种有效策略。为了实现此目标,催化剂的开发与设计是ECR研究的关键。单原子催化剂(SACs)因其独特的电子结构、明确的配位环境和极高的... 详细信息

电催化二氧化碳还原(ECR)制备高值化学品被认为是在碳中和背景下实现可再生能源存储及降低CO浓度的一种有效策略。为了实现此目标,催化剂的开发与设计是ECR研究的关键。单原子催化剂(SACs)因其独特的电子结构、明确的配位环境和极高的原子利用率,近年来在ECR领域引起了广泛关注。通过调节SACs的中心金属元素种类和局部配位结构,可有效调节SACs对CO和其还原中间体的吸附强度和催化活性。本文总结了SACs在ECR领域所取得的最新研究进展,重点讨论了SACs的配位结构及其与载体之间的相互作用对催化活性的影响以及相关调控策略,最后,提出了SACs应用于ECR所面临的机遇与挑战。

关键词：二氧化碳还原单原子催化剂电催化配位结构修饰

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Optofluidic transport and assembly of nanoparticles using an all-dielectric quasi-BIC metasurface

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Light(Science & Applications) 2023年第9期12卷 1771-1781页

作者： Sen Yang justus C.Ndukaife Department of Electrical and Computer Engineering Vanderbilt UniversityNashvilleTNUSA Interdisciplinary Materials Science Vanderbilt UniversityNashvilleTNUSA Full list of author information is available at the end of the article

Manipulating fluids by light at the micro/nanoscale has been a long-sought-after goal for lab-on-a-chip *** heating has been demonstrated to control microfluidic dynamics due to the enhanced and confined light absorption from the intrinsic losses of ***,the counterpart of metals,has been used to avoid undesired thermal effects due to its negligible light ***,we report an innovative optofluidic system that leverages a quasi-BIC-driven all-dielectric metasurface to achieve subwavelength scale control of temperature and fluid *** experiments show that suspended particles down to 200 nanometers can be rapidly aggregated to the center of the illuminated metasurface with a velocity of tens of micrometers per second,and up to millimeter-scale particle transport is *** strong electromagnetic field enhancement of the quasi-BIC resonance increases the flow velocity up to three times compared with the off-resonant situation by tuning the wavelength within several nanometers *** also experimentally investigate the dynamics of particle aggregation with respect to laser wavelength and power.A physical model is presented and simulated to elucidate the phenomena and surfactants are added to the nanoparticle colloid to validate the *** study demonstrates the application of the recently emerged all-dielectric thermonanophotonics in dealing with functional liquids and opens new frontiers in harnessing non-plasmonic nanophotonics to manipulate microfluidic ***,the synergistic effects of optofluidics and high-Q all-dielectric nanostructures hold enormous potential in high-sensitivity biosensing applications.

关键词： dielectric quasi negligible

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Characterization of the infectivity of an Indonesian Zika virus strain in mammalian cell lines

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Asian Pacific Journal of Tropical Biomedicine 2024年第5期14卷 215-224页

作者： justus Thomas Obiajulu Sievers Anom Bowolaksono R.Tedjo Sasmono Graduate School of Biology Department of BiologyFaculty of Mathematics and Natural SciencesUniversitas IndonesiaDepok 16424Indonesia Eijkman Research Center for Molecular Biology National Research and Innovation AgencyCibinong 16911Indonesia Cellular and Molecular Mechanisms in Biological System Research Group Department of BiologyFaculty of Mathematics and Natural SciencesUniversitas IndonesiaDepok 16424Indonesia

Objective:To characterize the infection patterns and growth characteristics of the Zika virus(ZIKV)strain JMB-185 from Indonesia in various mammalian cell ***:ZIKV was grown in human(A549,HEK293,HepG2,Huh7,Jurkat,and THP-1)and non-human mammalian(RAW264.7,Vero,and Vero76)cell *** replication kinetics were measured using plaque assay,while intra-and extracellular viral RNA concentrations were assessed using *** cytometry was used to quantify the infected cells and cell viability was measured using an MTT *** ability of ZIKV to infect cell lines was visualized using a fluorescence immunostaining ***:This ZIKV strain preferentially infected the lung,kidney,and liver cell lines A549,HEK293,Huh7,Vero,and Vero76,but not the immune cells Jurkat,RAW264.7,and *** contrast,the ZIKV showed no sign of infection in HepG2 cells,while maintaining viral titer over 3 days post-infection,with no infection recorded in immunostaining,no increase in viral RNA,and no indication of cell ***:The Indonesian ZIKV strain has a similar infection profile as other strains,except for its poor infectivity on HepG2 *** on the growth characteristics of Indonesia ZIKV will help expand our understanding of the biology of ZIKV which will be useful for various applications including antiviral discovery.

关键词： Zika virus Infectivity Replication Cell lines In vitro

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Application of quantum computing in discrete portfolio optimization

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Journal of Management Science and Engineering 2023年第4期8卷 453-464页

作者： justus Shunza Mary Akinyemi Chika Yinka-Banjo Operations Research&Information Engineering Cornell University36 Hoy RoadIthaca14853New YorkUnited States Department of Mathematics University of LagosAkokaLagos101017LagosNigeria Department of Computer Sciences University of LagosAkokaLagos10101zLagosNigeria

This study proposes a novel and more efficient quantum algorithm for portfolio optimization using quantum combinatorial optimization(Qco)techniques.A recent construction developed in 2021 has sparked the field of financial portfolio optimization through the Quantum Walk Optimization Algorithm(QWOA).In this study,we investigated the complexity and efficiency of quantum optimization algorithms with a special interest in *** objective is to minimize investment risk by having a good combination of assets in the *** also focused on reducing the number of iterations while attaining a high-quality resolution through contraction of the solution space to ease *** concept of QwOA was extended by constructing a newly outperforming scheme known as the"Quantum Mix Optimization Algorithm(QMOA)."QMOA algorithm codes were provided for the implementation and simulation of numerical *** addition,the efficiency of QMOA,which is better than the existing QCO algorithms,was *** instance,the least QWOA number of computations required to execute the initial state equation was p>2,whereas this value was p≥2 in the proposed QMOA.

关键词： Combinatorial optimization Induced tadpolegraph Lattice Qubits Trajectory

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Tunable colors and conductivity by electroless growth of Cu/Cu2O particles on sol-gel modified cellulose

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Nano Research 2020年第10期13卷 2658-2664页

作者： justus Landsiedel Waleri Root Christian Schramm Alexander Menzel Steffen Witzleben Thomas Bechtold Tung Pham Research Institute for Textile Chemistry and Textile Physics University of Innsbruck6850 DornbirnAustria Department of Physical Chemistry University of Innsbruck6020 InmsbruckAustria Department of Natural Sciences Bonn Rhein sSieg University of Applied Sciences5359 RheinbachGermany

Development of colored surfaces by formation of nano-structured aggregates is a widely used strategy in nature to color lightweight structures (e.g. butterflies) without the use of dye pigments. The deposition of nanoscale particles mimics nature in it’s approach coloring surfaces. This work presents sol-gel modification of cellulose surfaces used to form a template for growth of Cu/Cu2O core–shell particles with defined size-distributions. Besides improving the adhesion of the deposited particulate material, the sol-gel matrix serves as a template for the control of particle sizes of the Cu/Cu2O structures, and as a consequence of particle size variation the surface color is tunable. As an example, red color was achieved with an average particle size of 35 nm, and shifts gradually to blue appearance when particles have grown to 80 nm on the sol-gel modified fabric. The copper concentration on representative fabrics is kept low to avoid modifying the textile characteristics and were all in the range of 150–170 mg per g of cellulose material. As a result of copper deposition on the surface of the material, the cellulose fabric also became electrically conductive. Remarkably, the electrical conductivity was found to be dependent on the average particle sizes of the deposits and thus related to the change in observed color. The generation of color by growth of nano-sized particles on sol-gel templates provides a highly promising approach to stain surfaces by physical effects without use of synthetic colorants, which opens a new strategy to improve environmental profile of coloration.

关键词： electroless copper deposition sol-gel support thin film structural coloration tunable sheet resistance LSPR

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Some Properties of Skew Ornstein-Uhlenbeck Processes with Two Barriers

Some Properties of Skew Ornstein-Uhlenbeck Processes with Tw...

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作者： justus Oyaro Masese 河北工业大学

学位级别：硕士

The goal of this work is to study the properties of Skew Ornstein-Uhlenbeck processes with two control barriers in terms of Sturm-Liouville eigenfunction ex-pansion and characterize the spectrum from the behaviour of infinitesimal param-eters near the boundaries[r0,r1].We assume that the process starts from a random position x（0）∈[r0,r1]and it is confined to remain within the ***-ally,stochastic processes do not stay within boundaries,neither are they allowed to cross a certain *** main contribution is to give an explicit spectral representation for the hit-ting time densities of Skew Ornstein-Uhlenbeck processes in terms of their asso-ciated Sturm-Liouville eigenfunction expansion between the two control *** Sturm-Liouville eigenfunction expansion provides a good alternative to nu-merical Laplace approach when it comes to recovering the *** will classify feller’s natural boundaries and give large-n eigenvalue and eigenfunction asymptotics in terms of elementary *** has already been shown see e.g[23]that eigenfunction expansion method is more suitable than numerical Laplace transform inversion *** is basically because numerical integration is not required in eigenfunction expansion thus the cost of computation is *** Laplace transform is exact and accurate but because each wavelength must be resolved,this makes its cost to be *** they are limited to low *** the end of this thesis,we will give a numerical example of Skew Ornstein Uhlenbeck process on[-2,2].We reveal that eigenvalues have a linear growth as n increases and that the series converges slower.

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