Adsorption and surface reactions of C2H2 and C2H4 on Co(0001)

Abstract

Abstract In this paper we have studied adsorption and surface reactions of acetylene and ethylene on Co(0001) in detail by temperature desorption spectrum (TDS), X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). C 2 H 4 adsorption at 130 and 300 K followed by subsequent heating mainly forms C 2 clusters and graphitic carbon, respectively, while C 2 H 4 decomposes at 400 and 500 K to form dominant graphitic carbon and carbon adatoms, respectively. C 2 H 2 molecularly adsorbs at 130 K but exclusively dehydrogenates upon heating. The resulting C 2 H 2 (a) species at low coverages remains stable up to 400 K and then exclusively dehydrogenates into C 2 clusters, while the resulting C 2 H 2 (a) species at high coverages remains stable up to 310 K and then majorly dehydrocyclizates into (C 2 H) n intermediates with ring structures at 340 K which further dehydrogenates into graphitic carbon, and minorly dehydrogenates into C 2 clusters. Exposed at 370 K, C 2 H 2 dehydrocyclizates into (C 2 H) n intermediates with ring structures. These temperature and coverage dependent surface reactions of C 2 H 2 and C 2 H 4 on Co(0001) greatly enrich our fundamental understanding of Co-catalyzed F-T synthesis reaction.