“…Since the pioneering work by Hori et al, it has been known that particular oxophilic materials, e.g., Sn, − Pb, Cd, Tl, and In, favor CO 2 RR pathways toward formate production. However, debate continues regarding the mechanistic role of the respective metal oxides, which are either formed in situ during electrolysis or applied directly as the catalyst (precursor). − Advanced operando techniques, e.g., vibrational ,− and X-ray absorption spectroscopy, − have been successfully employed to gain deeper mechanistic insight into the electrolysis time, current density, and potential-dependent activation of CO 2 RR catalysts under operating conditions. , A recent example is based on the use of oxidic bismuth electrocatalysts, ,, which had already demonstrated superior selectivities toward formate production in classical H-type cell testing environments, with Faradaic efficiencies (FEs) exceeding 95% within an extraordinarily (approximately 1.1 V) , wide potential window. For a CO 2 -saturated 0.5 mol dm –3 KHCO 3 electrolyte solution, a combination of electrochemical analysis and operando Raman spectroscopy during CO 2 RR revealed the coupling of two potential-dependent CO 2 RR pathways as the origin of this superior catalytic performance .…”