Atomic-scale modulation of Cu2O patterned surfaces: Elucidating structure-dependent gas molecule-surface interactions for dual-functionality in adsorption and separation

Surfaces and Interfaces. 2025. Vol. 72. Article 107042.

Wang Z., Huang H., Ostovari Moghaddam A., Szilágyi B., Bai F.

As a highly promising semiconductor catalytic material, cuprous oxide (Cu2O) exhibits surface-dependent performance that is fundamentally governed by its atomic coordination environment. In this work, density functional theory (DFT) simulations systematically explored all potential steady-state surface configurations of Cu2O (100) under operando conditions, particularly focusing on restabilized 2-/3-coordinated O and Cu terminations. Three distinct operando patterned surface microstructures (G1, G2, and G3) were successfully established and characterized for the facet (100), with their thermal stability rigorously verified through ab initio molecular dynamics (AIMD) simulations. We comprehensively examined the adsorption behaviors of key industrial gases (CO, CO2, NO, NO2, N2O, SO2) across variable operando environments. Adsorption energy evaluations reveal N2O’s minimal sensitivity to surface grooves under working conditions. The G1 configuration (2-coordinated O) strengthens COx adsorption while suppressing NO2 binding. Cu-enriched G2 surfaces promote generalized adsorption enhancement (particularly for NOx species), whereas G3 (3-coordinated O) facilitates CO/CO2 separation through marked adsorption energy disparities. Adsorption-induced conductivity modulation exhibits system-specific characteristics: SO2 introduces a 0.33 eV bandgap in G1, while CO2 generates a 0.71 eV gap in G3. Bader charge analysis and charge density difference (CDD) mapping elucidate the electronic underpinnings of these adsorption variations. Extended investigations into multi-molecular adsorption regimes reveal configuration-dependent stability - CO2 maintains adsorption integrity through its rigid linear geometry (< 2 % structural deviation), contrasting with SO2’s adsorption-compromising bond distortions (> 10 %). These findings establish a theoretical framework for designing selective gas-sensing interfaces and optimizing heterogeneous catalytic systems through surface coordination engineering.

Keywords: DFT, Cu2O, Patterned surfaces, Gas adsorption and separation, Atomic-scale modulation

Publication based on the results of: Advanced materials and technologies (2025)