Dissociative Carbon Dioxide Adsorption and Morphological Changes on Cu(100) and Cu(111) at Ambient Pressures

Abstract

Ambient-pressure X-ray photoelectron spectroscopy (APXPS) and high-pressure scanning tunneling microscopy (HPSTM) were used to study the structure and chemistry of model Cu(100) and Cu(111) catalyst surfaces in the adsorption and dissociation of CO2. It was found that the (100) face is more active in dissociating CO2 than the (111) face. Atomic oxygen formed after the dissociation of CO2 poisons the surface by blocking further adsorption of CO2. This "self-poisoning" mechanism explains the need to mix CO into the industrial feed for methanol production from CO2, as it scavenges the chemisorbed O. The HPSTM images show that the (100) surface breaks up into nanoclusters in the presence of CO2 at 20 Torr and above, producing active kink and step sites. If the surface is precovered with atomic oxygen, no such nanoclustering occurs.

Subsurface oxide plays a critical role in CO 2 activation by Cu(111) surfaces to form chemisorbed CO 2 , the first step in reduction of CO 2

“…(C) The adsorption of CO 2 when a subsurface oxide structure is deliberately incorporated into Cu(111) but without additional H 2 O. In this work we observe that a subsurface oxide coverage of about 0.08 ML is responsible for stabilizing l-CO 2 determining the initial species formed while exposed to realistic gas pressures of CO2 and H2O (13,15).…”

“…2D, experimental condition A). Such subsurface adsorbed O (denoted Cu-O sub ) has been observed often near the Cu surface, most likely resulting from oxygen impurities in the chamber (28) or partial dissociative adsorption of CO2 (13). Interestingly, even if CO2 is still in a linear configuration (similar to the gas phase), we observe experimentally that the O 1s and C 1s core-level BEs of l -CO2 shift downward by ∼4.9 eV compared with g-CO2 (Fig.…”

“…A similar phenomenology was also observed by Rasmussen et al (9) on clean Cu(100) for CO2 pressures of about 740 Torr and temperatures in the range of 475-550 K (finding an activation energy of about 93 kJ·mol −1 ). On the other hand, a recent study by Eren et al (13) performed at much lower CO2 partial pressures (between 0.05 Torr and 10 Torr) revealed that CO2 can dissociatively adsorb on Cu(100) and Cu(111) with the consequent formation of surface oxygen as well. Indeed it has been suggested that the CO2 might dissociate more easily on preoxidized Cu surfaces (3), but there is little evidence to support this important concept.…”

Catalytic Intermediates of CO2 Hydrogenation on Cu(111) Probed by In Operando Near‐Ambient Pressure Technique

“…[11,[18][19][20][21][22] The conventional electron and ion probes are ineffective owing to their favored operation conditions of very low pressures, under which catalytic surfaces may be substantially different from those at ambient pressures, especiallyf or the adsorption of low-sticking species. [11,[18][19][20][21][22] The conventional electron and ion probes are ineffective owing to their favored operation conditions of very low pressures, under which catalytic surfaces may be substantially different from those at ambient pressures, especiallyf or the adsorption of low-sticking species.…”

Dynamic Changes in the Structure, Chemical State and Catalytic Selectivity of Cu Nanocubes during CO2 Electroreduction: Size and Support Effects

“…[1] Among these parameters,t he catalyst structure and chemical state are of particular importance. [7,8,16,21,[30][31][32][33][34][35][36] However,t he presence of (100) facets is not the only factor responsible for the superior activity and selectivity of cubeshaped Cu catalysts,w ith surface roughness,s ubsurface oxygen and Cu I species or Cu/Cu I interfaces formed and/or stabilized under reaction conditions also playing av ery important role. [20][21][22][23][24][25][26][27][28][29] Previous studies [9][10][11] on Cu single crystals have shown the improved C À Cc oupling performance of (100) facets,w hich was further confirmed by the high selectivity towards ethylene observed on cube-shaped Cu catalysts.…”