Thermal Oxidation of WSe2 Nano-sheets Adhered on SiO2/Si Substrates
Yingnan Liu, Cheng Tan, Harry Chou, Avinash Nayak, Di Wu, Rudresh Ghosh, Hsiao- Yu Chang, Yufeng Hao, Xiaohan Wang, Joon-Seok Kim, Richard Piner, Rodney S. Ruof… 展开作者
Yingnan Liu, Cheng Tan, Harry Chou, Avinash Nayak, Di Wu, Rudresh Ghosh, Hsiao- Yu Chang, Yufeng Hao, Xiaohan Wang, Joon-Seok Kim, Richard Piner, Rodney S. Ruoff, Deji Akinwande, Keji Lai
Due to the drastically different intralayer versus interlayer bonding strengths, the mechanical, thermal, and electrical properties of two-dimensional (2D) materials are highly anisotropic between the in-plane and out-of-plane directions. The structural anisotropy may also play a role in chemical reactions, such as oxidation, reduction, and etching. Here, the composition, structure, and electrical properties of mechanically exfoliated WSe2 nano- sheets on SiO2/Si substrates were studied as a function of the extent of thermal oxidation. A major component of the oxidation, as indicated from optical and Raman data, starts from the nano-sheet edges and propagates laterally towards the center. Partial oxidation also occurs in certain areas at the surface of the flakes, which are shown to be highly conductive by microwave impedance microscopy. Using secondary ion mass spectroscopy, we also observed extensive oxidation at the WSe2/SiO2 interface. The combination of multiple microcopy methods can thus provide vital information on the spatial evolution of chemical reactions on 2D materials and the nanoscale electrical properties of the reaction products.
Effect of surface nanostructure on temperature programmed reaction spectroscopy: First-principles kinetic Monte Carlo simulations of CO oxidation at RuO2(110)
CO Oxidation Catalysed by Pd-based Bimetallic Nanoalloys
基于密度泛函理论的全局几何优化已被用来证明催化团簇的几何结构对Pd基纳米合金上CO氧化反应的能垒的关键影响。我们发现，反应中间体之间的巨大几何变化可能导致非常高的能量势垒，从而对整个过程是禁止的。这对新催化剂的设计和所采用的理论方法都提出了挑战。在理论方面，仔细选择所有反应中间体的几何构型对于充分描述可能的反应路径是至关重要的。从催化剂设计的角度来看，可以通过调节团簇和掺杂剂金属之间的相互作用水平来控制团簇的几何构型，以及通过在单个纳米合金颗粒中混合不同的金属而在吸附物分子和催化剂簇之间进行。我们发现，Pd $_{5}$簇中的Pd原子与单个Ag原子的取代形成Pd $_{4}$ Ag $_{1}$导致簇的CO氧化反应的催化性能的潜在改善。另一方面，一个单一的金原子不提高催化剂的性能，这是由于集群的组成金属和吸附分子之间的较弱的杂化。这种灵活性的性质的x-nanoalloy集群说明微调的可能性，这可能是用于设计新的高效催化材料。
Oxidation of Tantalum Nano-Film by Microwave Exposure
The Institute of Science Tokyo（东京科学大学）；Center for Physical Sciences and Technology (FTMC)（物理与技术中心）；Swinburne University of Technology（斯威本科技大学）；Melbourne Centre for Nanofabrication (MCN)（墨尔本纳米制造中心）；Vilnius University（维尔纽斯大学）；Institute of Innovative Research, Institute of Science Tokyo（东京科学大学创新研究院）
Wafer-Scale Fabrication of Hierarchically Porous Silicon and Silica Glass by Active Nanoparticle-Assisted Chemical Etching and Pseudomorphic Thermal Oxidation
CO oxidation by Pt2/Fe3O4: metastable dimer and support configurations facilitate lattice oxygen extraction
基于亚纳米金属簇的多相催化剂通常表现出强烈的尺寸依赖性，并且添加或去除单个原子可以产生所有差异。然而，识别最活跃的物种并破译反应机理是极其困难的，因为通常不清楚催化剂如何在操作中演变。在这里，我们利用原子分辨扫描探针显微镜，光谱技术，和密度泛函理论（DFT）为基础的计算相结合，研究CO氧化模型Pt/Fe 3 O 4（001）单原子催化剂。我们表明，（PtCO）2二聚体，通过移动Pt-羰基物种的团聚动态形成，催化涉及的氧化物载体形成CO2的反应。Pt 2二聚体产生一个CO2分子，然后分裂成两个吸附原子，释放第二个CO。有趣的是，Olattice提取只有变得容易时，Pt-二聚体和Fe 3 O 4支持可以访问亚稳配置，这表明大量的，协调一致的重排簇和支持必须考虑在高温下发生的反应。
Oxidation-resilient structural modifications in Nickel-functionalized 3D-graphene for hydrogen storage applications
Istituto Nanoscienze–CNR（意大利国家研究委员会纳米科学研究所）；NEST-Scuola Normale Superiore（新实验科学与技术学院-高等师范学校）；Department of Physical Science, Earth, and Environment, University of Siena（锡耶纳大学地球与环境物理科学系）；Institute of Sensor and Actuator Systems, TU Wien（维也纳工业大学传感器与致动器系统研究所）；CNR - Istituto Officina dei Materiali (IOM)（意大利国家研究委员会材料工厂研究所）
