Interfacial Accumulation and Stability Enhancement Effects Triggered by Built‐in Electric Field of SnO ₂ /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.