Molecule Modification Enhancing the CO2 Electroreduction Performance on Au/Ag Bimetallic Spiky Nanostars Investigated by SERS.

The electrochemical carbon dioxide (CO2) reduction reaction is a promising approach to mitigate atmospheric CO2 accumulation and achieve carbon neutrality, but it is severely limited by low catalytic activity, poor selectivity, and the competing hydrogen evolution reaction (HER). Herein, a 3-aminopropyltriethoxysilane (APTES) molecule modification of spiky bimetallic Au/Ag nanostars is designed to enhance the catalytic activity and selectivity and suppress the HER for the CO2 electroreduction to CO. A remarkable CO Faraday efficiency was increased by 20% from 61% to 81% at -0.9 V vs reversible hydrogen electrode after the APTES modification, along with enhanced catalytic activity and stability. Operando electrochemical surface-enhanced Raman spectroscopy reveals APTES modification not only stabilizes the key *COOH intermediate to promote its conversion to *CO but also tailors the interfacial water structure rendering K+-H2O to strengthen CO2 activation and suppress HER. This study proves molecular modification is an efficient way to enhance CO2 electroreduction performance, providing a rational design strategy for high-selectivity CO2 electroreduction electrocatalysts.