Temperature-Controlled CO Adsorption Configurations on (2 × 1)Ni–O/Ni(110) Surfaces

Abstract

CO adsorptions and configuration evolutions with temperatures on (2 × 1)Ni–O row structures on Ni(110) surfaces were studied by using ultrahigh vacuum–Fourier transform infrared spectroscopy, thermal desorption spectroscopy, and density functional theory calculations. Two kinds of adsorption configurations were identified. In the top configuration at low temperature (90 K), the carbon atom of one CO binds to one Ni atom in the Ni–O rows with a tilt angle of about 53°, and the vibration frequency of CO is 2100–2119 cm–1 depending on CO coverage. In the bridge configuration near room temperature (280 K), the carbon atom of one CO binds to two Ni atoms from the neighboring Ni–O rows, and the vibration frequency is 2030–2039 cm–1. By annealing the sample prepared at 90 to 280 K, the top adsorption configuration gradually evolves into the ordered bridge adsorption configuration via a disordered state. In the disordered state, the top and bridge configurations are distributed in disorder, induce strong transver...