Computational Screening of N-Doped Graphene-Supported Cu-Sc Nanoclusters for CO 2 Capture

Converting carbon dioxide (CO 2 ) into value-added chemicals and/or capturing it before emission are complementary strategies to mitigate rising atmospheric CO 2 levels. Copper-based materials are widely investigated for CO 2 conversion because Cu can bind and electronically activate CO 2 and related intermediates. In this computational research, an evaluation of CO 2 activation in Cu x Sc γ nanoclusters (Cu 3 Sc, Cu 2 Sc 2 , and CuSc 3 ) anchored on a graphene bilayer doped with three nitrogen atoms (graphene-3N) was performed using conformational screening and thermochemical adsorption analysis at 298.15, 300, and 400 K. Initially, the Cu 3 Sc, Cu 2 Sc 2 , and CuSc 3 nanoclusters were optimized and characterized (relative energy, multiplicity, and electronic characteristics), and the support model (graphene-3N bilayer) was validated by comparing free geometry with partially restricted geometry, corroborating minima through vibrational analysis. Subsequently, CO 2 adsorption/activation on Cu x Sc γ @graphene-3N was evaluated, and ΔH and ΔG values were calculated. Ultimately, based on the ΔG(T) values, the Sabatier regimes were established, where it was observed that Cu 3 Sc exhibits moderate exergonic adsorption (ΔG = −76.07, −67.31, and −58.92 kJ·mol −1 at 298.15, 350, and 400 K). In contrast, Cu 2 Sc 2 exhibits intense adsorption (−165.02, −156.36, and −148.04 kJ·mol −1 ), and CuSc 3 results in practically irreversible fixation (−293.98, −287.32, and −279.09 kJ·mol −1 ), giving priority to Cu 3 Sc as the most optimal cluster in terms of activation-regeneration.