Inherently Area-Selective Atomic Layer Deposition of Manganese Oxide through Electronegativity-Induced Adsorption

Manganese oxide (MnOx) shows great potential in the areas of nano-electronics, magnetic devices and so on. Since the characteristics of precise thickness control at the atomic level and self-align lateral patterning, area-selective deposition (ASD) of the MnOx films can be used in some key steps of nanomanufacturing. In this work, MnOx films are deposited on Pt, Cu and SiO2 substrates using Mn(EtCp)2 and H2O over a temperature range of 80–215 °C. Inherently area-selective atomic layer deposition (ALD) of MnOx is successfully achieved on metal/SiO2 patterns. The selectivity improves with increasing deposition temperature within the ALD window. Moreover, it is demonstrated that with the decrease of electronegativity differences between M (M = Si, Cu and Pt) and O, the chemisorption energy barrier decreases, which affects the initial nucleation rate. The inherent ASD aroused by the electronegativity differences shows a possible method for further development and prediction of ASD processes.

A computational study on Pt and Ru dimers supported on graphene for the hydrogen evolution reaction: new insight into the alkaline mechanism

The dissociative chemisorption energy of water was proposed to address both thermodynamics and kinetics of alkaline hydrogen evolution.

Correlation between the acid–base properties of the La2O3 catalyst and its methane reactivity

The linear relationship between CH4 activation energy and CO2 chemisorption energy illuminates the high OCM activity of strongly basic La2O3 catalysts.

First Principle Calculation of CO Chemisorption on δ-Pu(001) Surface

Chemisorption of CO molecule on the (001) surface of δ-Pu using the generalized gradient approximation of the density functional theory with the Perdew-Burke-Ernzerhof exchange-correlation functional has been investigated without spin-orbit coupling at the non-spin-polarized level to better understand the interaction and chemical reaction of CO with Pu surface. Band structure and density of states before and after CO molecule chemisorption on the bridge position of the (001) surface have been compared and analyzed. The result shows that s and p states of CO molecule hybrid with Pu 6d states. Chemisorption energy for this adsorption site and repulsion energy between CO molecules are 0.615046eV and 0.96768eV, respectively.Key words: density functional;chemisorption;energy band;density of states;repulsion energy

THEORETICAL STUDY OF CO ADSORPTION ON Ni(111), Pt(111) AND Pt/Ni(111) SURFACES

CO adsorption on a pseudomorphic Pt overlayer supported by Ni (111) has been studied with the use of extended Huckel calculations. Experimental information on the pure Pt (111) and Ni (111) single crystals was employed to select a consistent parameter set for our bimetallic system. This gives a good description of the chemisorption bond changes between the various systems considered in our study. The CO chemisorption energy on Pt/Ni (111) was found to be lowered in comparison with Pt (111) and Ni (111), in good agreement with experimental data on Pt-rich Pt–Ni surface alloys. This observation could be justified by the electronic changes of the Pt states (valence band broadening and decreasing density at the Fermi level). Indeed, they induce, in comparison with the pure substrates, a repulsion between Pt and CO although the 2π* population of the chemisorbed molecule increases. This points to the necessity of going beyond arguments based on an analysis of the 5σ donation and 2π* backdonation for a complete description of the chemisorption bond.

A MODEL FOR THE MUTUAL INFLUENCE OF CHEMISORPTION AND MULTILAYER SEGREGATION

The Green function method and the chemisorption theory of Einstein and Schrieffer are used to calculate the chemisorption energies of O and CO on the multilayer segregated Ni-Cu disordered binary alloy within the many-coupled self-consistent coherent potential approximation. In general cases, the chemisorption-induced surface segregation can change the surface component and the chemisorption property to varying degrees. When the mutual influence of chemisorption and multilayer segregation is considered, the changes appear slightly mild. The chemisorption energy for O/Ni-Cu (CO/Ni-Cu) depends sensitively on O(CO) coverage θ, and decreases with increasing θ.