scholarly journals Coordination Number Regulation of Molybdenum Single-Atom Nanozyme Peroxidase-like Specificity

Chem ◽  
2020 ◽  
Author(s):  
Ying Wang ◽  
Guangri Jia ◽  
Xiaoqiang Cui ◽  
Xiao Zhao ◽  
Qinghua Zhang ◽  
...  
Keyword(s):  
Coordination Number ◽  
Single Atom

scholarly journals Regulating coordination number in atomically dispersed Pt species on defect-rich graphene for n-butane dehydrogenation reaction

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xiaowen Chen ◽  
Mi Peng ◽  
Xiangbin Cai ◽  
Yunlei Chen ◽  
Zhimin Jia ◽  
...  
Keyword(s):  
Coordination Number ◽  
Density Functional ◽  
Activation Barrier ◽  
Density Functional Theory Calculation ◽  
Catalytic Performance ◽  
Atomic Level ◽  
Metal Nanoparticle ◽  
Single Atom ◽  
Nano Structure ◽  
Theory Calculation

AbstractMetal nanoparticle (NP), cluster and isolated metal atom (or single atom, SA) exhibit different catalytic performance in heterogeneous catalysis originating from their distinct nanostructures. To maximize atom efficiency and boost activity for catalysis, the construction of structure–performance relationship provides an effective way at the atomic level. Here, we successfully fabricate fully exposed Pt3 clusters on the defective nanodiamond@graphene (ND@G) by the assistance of atomically dispersed Sn promoters, and correlated the n-butane direct dehydrogenation (DDH) activity with the average coordination number (CN) of Pt-Pt bond in Pt NP, Pt3 cluster and Pt SA for fundamentally understanding structure (especially the sub-nano structure) effects on n-butane DDH reaction at the atomic level. The as-prepared fully exposed Pt3 cluster catalyst shows higher conversion (35.4%) and remarkable alkene selectivity (99.0%) for n-butane direct DDH reaction at 450 °C, compared to typical Pt NP and Pt SA catalysts supported on ND@G. Density functional theory calculation (DFT) reveal that the fully exposed Pt3 clusters possess favorable dehydrogenation activation barrier of n-butane and reasonable desorption barrier of butene in the DDH reaction.

scholarly journals Shifting the scaling relations of single-atom catalysts for facile methane activation by tuning the coordination number

2021 ◽  
Author(s):  
Changhyeok Choi ◽  
Sungho Yoon ◽  
Yousung Jung
Keyword(s):  
Transition State ◽  
Coordination Number ◽  
Active Sites ◽  
Methane Activation ◽  
Single Atom ◽  
Scaling Relations ◽  
Scaling Relationship ◽  
Relationship Of

The scaling relationship of methane activation via a radical-like transition state shifts toward a more reactive region with decreasing coordination number of the active sites.

scholarly journals Tuning the coordination number of Fe single atoms for the efficient reduction of CO2

2020 ◽  
Vol 22 (21) ◽  
pp. 7529-7536
Author(s):  
Huihuang Chen ◽  
Xu Guo ◽  
Xiangdong Kong ◽  
Yulin Xing ◽  
Yan Liu ◽  
...  
Keyword(s):  
Coordination Number ◽  
Single Atom ◽  
Single Atoms ◽  
Electrocatalytic Performance ◽  
Efficient Reduction ◽  
Co Conversion ◽  
Reduction Of Co2

The coordination number of Fe single-atom catalysts (Fe–N5/Fe–N6) significantly affects the electrocatalytic performance during CO2-to-CO conversion.

Construction of Single-atom Copper Sites with Low Coordination Number for the Efficient CO2 Electroreduction to CH4

2021 ◽  
Author(s):  
Shaomin Wei ◽  
Xingxing Jiang ◽  
Congyi He ◽  
Siyu Wang ◽  
Qi Hu ◽  
...  
Keyword(s):  
High Temperature ◽  
Coordination Number ◽  
Strong Acid ◽  
Single Atom ◽  
Acid Etching ◽  
Co2 Electroreduction ◽  
Copper Sites ◽  
Harsh Conditions

Generally speaking, the preparation of single-atom catalysts always requires harsh conditions such as high-temperature pyrolysis or strong acid etching. In this manuscript, a simple and effective plasma-activated strategy is employed...

Conflicting Roles of Coordination Number on Catalytic Performance of Single-Atom Pt Catalysts

ACS Catalysis ◽  
2021 ◽  
pp. 5586-5592
Author(s):  
Dahong Huang ◽  
Ning He ◽  
Qianhong Zhu ◽  
Chiheng Chu ◽  
Seunghyun Weon ◽  
...  
Keyword(s):  
Coordination Number ◽  
Catalytic Performance ◽  
Single Atom ◽  
Pt Catalysts

Single Atom Image Contrast in Fixed Beam Dark Field Electron Microscopy

1974 ◽  
Vol 32 ◽  
pp. 366-367
Author(s):  
Wah Chi
Keyword(s):  
Scattering Amplitude ◽  
Present Report ◽  
Dark Field ◽  
Image Contrast ◽  
Single Atom ◽  
Optical Theorem ◽  
Hartree Fock ◽  
Heavy Atoms ◽  
Beam Stop ◽  
Fixed Beam

Resolution and contrast are the important factors to determine the feasibility of imaging single heavy atoms on a thin substrate in an electron microscope. The present report compares the atom image characteristics in different modes of fixed beam dark field microscopy including the ideal beam stop (IBS), a wire beam stop (WBS), tilted illumination (Tl) and a displaced aperture (DA). Image contrast between one Hg and a column of linearly aligned carbon atoms (representing the substrate), are also discussed. The assumptions in the present calculations are perfectly coherent illumination, atom object is represented by spherically symmetric potential derived from Relativistic Hartree Fock Slater wave functions, phase grating approximation is used to evaluate the complex scattering amplitude, inelastic scattering is ignored, phase distortion is solely due to defocus and spherical abberation, and total elastic scattering cross section is evaluated by the Optical Theorem. The atom image intensities are presented in a Z-modulation display, and the details of calculation are described elsewhere.

Atomic Spectroscopy in the FIM

1986 ◽  
Vol 44 ◽  
pp. 758-761
Author(s):  
J. J. Hren ◽  
S. D. Walck
Keyword(s):  
Electron Microscope ◽  
Electric Fields ◽  
Atom Probe ◽  
Atomic Spectroscopy ◽  
Single Atom ◽  
Statistical Sampling ◽  
Commercial Instrument ◽  
Available Technology ◽  
High Electric Fields ◽  
Field Ion Microscope

The field ion microscope (FIM) has had the ability to routinely image the surface atoms of metals since Mueller perfected it in 1956. Since 1967, the TOF Atom Probe has had single atom sensitivity in conjunction with the FIM. “Why then hasn't the FIM enjoyed the success of the electron microscope?” The answer is closely related to the evolution of FIM/Atom Probe techniques and the available technology. This paper will review this evolution from Mueller's early discoveries, to the development of a viable commercial instrument. It will touch upon some important contributions of individuals and groups, but will not attempt to be all inclusive. Variations in instrumentation that define the class of problems for which the FIM/AP is uniquely suited and those for which it is not will be described. The influence of high electric fields inherent to the technique on the specimens studied will also be discussed. The specimen geometry as it relates to preparation, statistical sampling and compatibility with the TEM will be examined.

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