Titration for basal plane versus edge plane surface on graphitic carbons by adsorption

The morphological instability appeared at step-free 4H-SiC (0001) surfaces was investigated. The step-free surfaces were fabricated at the bottom of inverted-mesa structure by the method combining a laser digging and Si-vapor etching. By repeated Si-vapor etching treatments, randomly created crater and maze structures were cyclically appeared at the step-free surfaces. These structures were distinctly classifiable by their depths from the step-free surfaces. Crater structures have 0.2 - 0.3 nm depth and maze structures have 0.5 nm depth. The morphological evolutions indicate the process of destruction of the step-free (0001) basal plane and generation of steps from step-free surfaces in the Si-vapor etching process.

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Steps of Surface Etching and Carbon Deposition on the Graphite Basal Plane

MRS Proceedings ◽

10.1557/proc-312-225 ◽

1993 ◽

Vol 312 ◽

Cited By ~ 1

Author(s):

Xi Chu ◽

Vincent Chan ◽

Lanny D. Schmidt

Keyword(s):

Single Crystal ◽

Vapor Deposition ◽

Basal Plane ◽

Carbon Deposition ◽

Chemical Vapor ◽

Reaction Rates ◽

Plane Versus ◽

Graphite Basal Plane ◽

Kinetics Of

AbstractThe reactions of O2, H2O, CO2, NO2, NO, and N2O with single crystal graphite between 400 and 700°C have been studied by STM to obtain quantitative kinetics by measuring the number and size of monolayer pits on the basal plane versus temperature and time. At low temperature the reaction initiates exclusively from the point defects on the basal plane to form monolayer pits. The shape of the monolayer pits vary from nearly triangular to hexagonal to circular depending on the rate of the reaction and the reacting gases. The sizes of the monolayer pits grow linearly with reacting time. The monolayer reaction rates follow the order of RNO2 > RN2O > RNO > RO2 > RH2O > RCO2. The activation energies for reactions with O2, H2O, NO2, NO, and N2O, are determined to be 127, 205, 60, 89, and 74 kJ/mol respectively.Carbon deposition from hydrocarbons onto surfaces of single crystal graphite has been examined to study the fundamental steps of chemical vapor deposition. Uniform monolayer pits on graphite surface were first produced by reactive etching of freshly cleaved single crystal of graphite in oxygen and carbon was then made to deposit exclusively on these defects in the basal plane. Carbon vapor deposition forms unique structures around the monolayer steps. By measuring the sizes of structures on steps in various gases versus temperature and pressure, the kinetics of hydrocarbon decomposition and the role of surface diffusion can be determined.

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Unravelling the electrocatalytic activity of bismuth nanosheets towards carbon dioxide reduction: edge plane versus basal plane

Applied Catalysis B Environmental ◽

10.1016/j.apcatb.2021.120693 ◽

2021 ◽

pp. 120693

Author(s):

Dan Wang ◽

Kuan Chang ◽

Yaning Zhang ◽

Yanying Wang ◽

Qixin Liu ◽

...

Keyword(s):

Carbon Dioxide ◽

Basal Plane ◽

Electrocatalytic Activity ◽

Carbon Dioxide Reduction ◽

Plane Versus

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An Effective Pair-Potential Study of the Interaction of a Water Monomer with the Basal-Plane Surface of Ice Ih

Journal of Glaciology ◽

10.3189/s0022143000033918 ◽

1978 ◽

Vol 21 (85) ◽

pp. 704-704

Author(s):

B. N. Hale ◽

J. Kiefer

Keyword(s):

Binding Energy ◽

Basal Plane ◽

Plane Surface ◽

Pair Potential ◽

Surface Molecule ◽

Effective Pair Potential ◽

Effective Pair ◽

A Site ◽

Energy Surfaces ◽

Ice Model

AbstractThe central-force effective pair potential of Rahman and others (1975) is used to generate minimal binding-energy surfaces and configurations of a water monomer adsorbed on the unrelaxed basal plane surface of ice Ih. In the initial study H2O molecules arc placed with oxygen atoms fixed at the ice Ih lattice positions and associated hydrogens along the tetrahedral bond directions—restricting the H-O-H bond angles to 109.5°. A rigid-body water monomer adsorbed on the surface interacts with all the H2D molecules in the bulk ice model via the central-force effective pair potential. The center-of-mass height, z, and the dipole orientation of the adsorbed H2O molecule are varied to minimize the total binding energy of the monomer over a particular (x,y) point of the surface. Preliminary results showed that a rigid adsorbed monomer with an H-O-H angle fixed at 104.5° produced only minor deviations in the binding-energy surfaces and that a large bulk-ice model (486 molecules) gave effectively the same results as a smaller ice model (50 molecules). Studies on an infinite ice surface using periodic boundary conditions are in progress and will be used to study surface relaxation and long-range effects on the minimal energy surfaces. Three types of sites on the basal plane were considered: (1) a site with all surface molecule protons pointing out of the surface; (2) a site with all surface molecule protons pointing into the surface; and (3) a site with all rows of surface molecule protons pointing alternately into and out of the surface. A "site" generally refers to a region (about 90 Å2) on the surface over which the minimal binding-energy surface is to be determined.Minimal binding-energy surfaces for the sites have been obtained together with plots showing the surface of the position of the center of mass as a function of x and y. This is a model calculation and is limited by the validity of the potential under close scrutiny. However it gives a qualitative picture of how complex a terrain the real ice Ih surface might present to an adsorbed water molecule and how the water molecule might diffuse from site to site. From these calculations (and in the spirit of this model potential) a value for the mean path length and the mean residence time of the adsorbed water monomer can be estimated.

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