Interfacial Accumulation and Stability Enhancement Effects Triggered by Built‐in Electric Field of SnO2/LaOCl Nanofibers Boost Carbon Dioxide Electroreduction

Abstract Constructing a built‐in interfacial electric field (BIEF) is an effective approach to enhance the electrocatalysts performance, but it has been rarely demonstrated for electrochemical carbon dioxide reduction reaction (CO 2 RR) to date. Herein, for the first time, SnO 2 /LaOCl nanofibers (NFs) with BIEF is created by electrospinning, exhibiting a high Faradaic efficiency (FE) of 100% C 1 product (CO and HCOOH) at −0.9–−1.1 V versus reversible hydrogen electrode (RHE) and a maximum FE HCOOH of 90.1% at −1.2 V RHE in H‐cell, superior to the commercial SnO 2 nanoparticles (NPs) and LaOCl NFs. SnO 2 /LaOCl NFs also exhibit outstanding stability, maintaining negligible activity degradation even after 10 h of electrolysis. Moreover, their current density and FE HCOOH are almost 400 mA cm −2 at −2.31 V and 83.4% in flow‐cell. The satisfactory CO 2 RR performance of SnO 2 /LaOCl NFs with BIEF can be ascribed to tight interface of coupling SnO 2 NPs and LaOCl NFs, which can induce charge redistribution, rich active sites, enhanced CO 2 adsorption, as well as optimized Gibbs free energy of *OCHO. The work reveals that the BIEF will trigger interfacial accumulation and stability enhancement effects in promoting CO 2 RR activity and stability of SnO 2 ‐based materials, providing a novel approach to develop stable and efficient CO 2 RR electrocatalysts.