Heteroatoms Induce Localization of the Electric Field and Promote a Wide Potential‐Window Selectivity Towards CO in the CO2 Electroreduction

Carbon dioxide electroreduction (CO2RR) is a sustainable way of producing carbon‐neutral fuels. Product selectivity in CO2RR is regulated by the adsorption energy of reaction‐intermediates. Here, we employ differential phase contrast‐scanning transmission electron microscopy (DPC‐STEM) to demonstrate that Sn heteroatoms on a Ag catalyst generate very strong and atomically localized electric fields. In situ attenuated total reflection infrared spectroscopy (ATR‐IR) results verified that the localized electric field enhances the adsorption of *COOH, thus favoring the production of CO during CO2RR. The Ag/Sn catalyst exhibits an approximately 100 % CO selectivity at a very wide range of potentials (from −0.5 to −1.1 V, versus reversible hydrogen electrode), and with a remarkably high energy efficiency (EE) of 76.1 %. Tin heteroatoms on a silver catalyst generate very strong and atomically localized electric fields, as disclosed by differential phase contrast‐scanning transmission electron microscopy (DPC‐STEM). This results in a 100 % selectivity for CO at a wide range of potentials (−0.5 V to −1.1 V vs. RHE).