Efficient and selective photocatalytic CO2 reduction over Ga single atom decorated quantum dots under visible light

Abstract

Exploring unique single atoms as catalytic sites is vitally important to improving the activity and selectivity of photocatalytic CO₂ reduction but remains challenging. Here, we find that gallium (Ga) single atoms can serve as effective active sites for boosting the photocatalytic CO₂ reduction reaction over CdSe quantum dots (QDs). Specifically, Ga single atom decorated CdSe QDs exhibit a CO evolution rate of 16.1 μmol h⁻¹ and a selectivity of 90.4% with excellent durability over 30 hours, which are much higher than those of bare CdSe QDs. The mechanism investigation indicates that the introduction of Ga single atoms into the lattice of CdSe QDs enables efficient separation of photogenerated electron–hole pairs and enhanced adsorption ability toward CO₂ molecules; meanwhile the surface Ga catalytic sites can effectively trap electrons to activate CO₂ and suppress H₂ evolution.