Adsorption Configuration Changes and Reactions of N2O on V(110) between 80 and 200 K

Abstract

Adsorption and reactions of N 2 O on V(110) have been investigated. The N 2 O molecule is adsorbed on V(110) through the terminal nitrogen atom at 80 K. The molecular axis of N 2 O is tilted from the surface, and the tilt angle is greater than 55°. The adsorption configuration of N 2 O changes in the temperature range of 80 to 120 K, and decomposition of N 2 O takes place to produce N 2 .The reaction of nitrogen oxides (NO x ) on metal and metal oxide surfaces has been the subject of numerous surface science studies. Nitrogen oxides are major components of air pollution, and the catalytic reaction of NO x on solid surfaces is important in environmental chemistry. In surface science studies of NO x , nitric oxide (NO) has been most extensively studied. 1 In the process of the NO reaction on solid surfaces, formation and desorption of nitrous oxide (N 2 O) has been frequently observed. 2To better understand the surface reaction of NO, it is crucial to investigate the adsorption and reactions of N 2 O on solid surfaces.In the present study the adsorption and reactions of N 2 O on V(110) have been investigated using X-ray photoelectron spectroscopy (XPS) and a near-edge X-ray absorption fine structure (NEXAFS) techniques. We will discuss the adsorption geometry change of N 2 O on V(110) in the process of the N 2 O reaction in the temperature range of 80 to 200 K.The XPS and temperature-programmed desorption (TPD) experiments were carried out in an ultrahigh vacuum (UHV) system whose base pressure was lower than 2 © 10 ¹10 Torr. The XPS spectra were recorded using a 300 W Al K¡ X-ray source and a hemispherical analyzer (model VG Cram 2). The NEXAFS experiment was performed at the 2B1 beam line of the Pohang Accelerator Laboratory, Korea. NEXAFS spectra were obtained by measuring partial electron yield using a hemispherical electron energy analyzer. The V(110) crystal was purchased from Metal Crystals and Oxides and cleaned by using a standard procedure. N 2 O was introduced to the analysis chamber using a leak valve.TPD was utilized to investigate the desorption products from the surface reaction of N 2 O on V(110).