Localized Surface Plasmon Resonance in Single-Atom Au₁Cu Alloy Promotes Asymmetrical C─C Coupling for CO₂...

The photocatalytic conversion of CO₂ and pure H₂O to ethanol has been challenged by low light utilization and sluggish C─C coupling kinetics. Here, single-atom Au₁Cu alloys are synthesized with enhanced localized surface plasmon resonance (LSPR) effects. A strong chemical interaction is probed as electron transfer from the atomic Au site to the adjacent Cu host, giving rise to electron rearrangement and an upshift of the d band center toward the Fermi level of Cu nanoparticles. As a result, the high electron occupancy state in Au₁Cu alloy is excited to abundant hot charge carriers under illumination. The catalyst with an optimal amount of gold dopants delivers an excellent ethanol yield of 940 µmol g_Au ^-1 h^-1 and a selectivity of 92.5% with outstanding stability exceeding 100 h. The structure-reactivity correlation and mechanism studies reveal that the LSPR effect induced by the doping of single-atom Au not only enhances light adsorption but also improves the accumulation of ^*CO intermediates, which accounts for the reduced energy barrier for C─C coupling toward ethanol formation.