Stability and Effects of Subsurface Oxygen in Oxide-Derived Cu Catalyst for CO₂ Reduction

Abstract

Oxide-derived copper (OD-Cu) catalysts are promising candidates for the electrochemical CO 2 reduction reaction (CO 2 RR) due to the enhanced selectivity toward ethylene over methane evolution, which has been linked to the presence of subsurface oxygen (O sb ). In this work, O sb is investigated with theoretical methods. Although O sb is unstable in slab models, it becomes stabilized within a "manually" reduced OD-Cu nanocube model which was calculated by self-consistent charge density functional tight binding (SCC-DFTB). The results obtained with SCC-DFTB for the full nanocube were confirmed with subcluster models extracted from the nanocube, calculated with both density functional theory (DFT) and SCC-DFTB. The higher stability of O sb in the nanocube is attributed to the disordered structure and greater flexibility. The adsorption strength of CO on Cu(100) is enhanced by O sb withdrawing electron density from the Cu atom, resulting in reduction of the σ-repulsion. Hence, the coverage of CO may be increased, facilitating its dimerization.

CO2 Reduction for C2+ in Seawater Using a Graphitic Frustrated Lewis Pair Catalyst

“…This thermodynamically favourable C2O3 formation contributes to the activation of subsequent hydrogenation steps and selectivity towards C2+ products. It is noteworthy that the present exothermic formation of C2O3 by CO-CO2 bonding is completely different from previously reported mechanisms that have endothermic CO-CO coupling steps for C2+ production 5,11,12,[42][43][44] . The exothermic formation of Supplementary Fig.…”

An overview of Cu-based heterogeneous electrocatalysts for CO2reduction

“…Many groups 82,95,149,150 proved that the Cu + site is key for enhanced activity and remained on the catalyst surface during the reaction. Some groups 96,151,152 found that sub-surface oxygen stabilized in reduced oxide-derived Cu plays an important role and there is synergy between surface Cu + and surface Cu 0 sub-oxide species.…”

Oxygen induced promotion of electrochemical reduction of CO2 via co-electrolysis

“…Although there is a general recognition of the beneficial effect of oxidative treatments on Cu-based catalysts in the CO 2 reduction reaction (CO 2 RR), the mechanisms through which the enhancement is realized remain a topic of considerable discussion. A key point of debate is whether oxygen-containing species, e.g., CuO x , CuO x (OH) y , and Cu (OH) x , are present at the CO 2 RR conditions 6,7,[10][11][12][13][14][15][16][17][18][19] . Multiple ex situ and in situ/operando characterizations lead to contradicting conclusions 6,7,[10][11][12][13][14][15][16][17]19 .…”