Enhanced CO2 reduction on transition metal-doped AlN and GaN quantum dots: A DFT study

Abstract

Two-dimensional AlN and GaN quantum dots were studied using density functional theory (DFT) to explore the effects of doping with light elements (C, Si, O, S) and metal atoms (Mo, Rh, Ag, Os, Ir, Au, Bi, As, Sn). Binding energy and vibrational frequency analyses confirmed the stability of the structures. Pristine nanodots were found to be insulators with a wide energy gap (~5 eV), which decreased significantly with doping, reaching 1.90 eV and 1.62 eV for S and Ag, respectively. UV–vis spectra supported the electronic calculations, showing a similar decrease in the optical gap. While pristine GaN and AlN required high energy for CO₂ reduction, doping with metals, particularly Rh and Ir, significantly lowered energy barriers for *COOH and *CO formation and CO release. Additionally, Rh and Ir-doped quantum dots demonstrated selectivity for CO₂ reduction over hydrogen evolution, highlighting their potential as efficient catalysts for sustainable CO₂ conversion.