In order to validate our theoretical findings, preliminary in-situ electrochemical SERS measurements were performed to probe polycrystalline Ag catalyst surface during CO 2 ER in 0.05 M Li 2 B 4 O 7 17 saturated with CO 2 , with a bulk pH of 6.1 (Experimental details in SI). We observe a double-band shape at 1436 and 1469 cm -1 (Figure ) corresponding to an O-bound bidentate intermediate on the Ag surface, which we believe to be the * OCHO species based on similar evidence obtained in literature for carboxylate species on silver hydrosols. The interactions of O-bound species with the Ag surface appear at relatively low overpotentials (-0.52 V vs RHE), in agreement with the obtained theoretical results.