Chemisorption

About: Chemisorption is a research topic. Over the lifetime, 16298 publications have been published within this topic receiving 554989 citations.

Adsorption and Surface Reactivity on Single-Walled Boron Nitride Nanotubes Containing Stone−Wales Defects

Abstract: Adsorption of chemical species H, O, CO, H2, O2, H2O, and NH3 on the sidewall of zigzag (8,0) and armchair (5, 5) boron nitride nanotubes (BNNTs) is studied using density-functional theory. Particular attention is paid to searching for the most-stable configuration of the adsorbates at a perfect site (PS) and near a Stone−Wales (SW) defect, and the surface reactivity at the PS and near the SW defect. Reactivity near the SW defect is generally higher than that at the PS because of the formation of frustrated B−B and N−N bonds and the local strain caused by pentagonal and heptagonal pairs. O2 is prone to dissociative chemisorption near SW defects, but is more likely physisorbed at the PS. The adsorption of H2O and NH3 on the sidewall of BNNT can be described as molecular chemisorption due to modest interaction between HOMO of H2O or NH3 with LUMO of BNNT. Adsorption of NH3 can affect electronic properties of BNNT through lifting the Fermi level. As such, NH3 can be viewed as an n-type impurity. CO and H2 ca...

Hydrolysis and Condensation of Self-Assembled Monolayers of (3-Mercaptopropyl)trimethoxysilane on Ag and Au Surfaces

Abstract: Self-assembled monolayer films of (3-mercaptopropyl)trimethoxysilane (3MPT) and their hydrolysis products on Ag and Au surfaces are characterized using Raman spectroscopy, FTIR spectroscopy, ellipsometry, X-ray photoelectron spectroscopy (XPS), and electrochemistry. 3MPT monolayers are formed through metal−thiolate bonding through the S atom on both metals, similar to other alkanethiol chemisorption chemistries. The orientation of 3MPT molecules in these monolayers is similar on both metals. Prior to hydrolysis, the molecules form an organized monolayer with the methoxy headgroups oriented largely parallel to the surface and the propyl chain in a largely trans conformation. When the methoxy groups are hydrolyzed, the 3MPT molecules cross-link through the formation of siloxane bonds. Although the surface vibrational spectroscopy indicates the presence of a small number of unreacted silanol groups on the siloxane surface, cyclic voltammetry of underpotential deposition of Pb suggests that the Si−O−Si networ...