Ultrastable Implanting‐Structured Catalyst for Long‐Lasting Acidic CO 2 Electrolysis with Industrial‐Level Current Densities

Abstract Acidic electrocatalytic CO 2 reduction reaction (CO 2 RR) holds promise for high CO 2 utilization. However, corrosive and reductive acidic electrolytes typically cause catalyst degradation and undesirable self‐reduction. In this study, we strategically design an implanting‐structured catalyst encompassing Bi 2 O 3 nanoparticles (NPs) core within zeolite crystals through a novel stepwise seed‐directed crystallization technique. This design potently inhibits the dissolution, detachment, agglomeration and reshaping of NPs during acidic CO 2 RR and precisely controls NP size to offer high‐density active sites per unit area. The concomitant strong metal oxide‐support interaction induces the electron shielding effect, which drives electrons unidirectionally exported from Bi to *OCHO intermediate and zeolite but prevents the electron inflow to Bi, preventing the working Bi 2 O 3 from self‐reduction during acidic CO 2 RR. Meanwhile, the interfacial electron transfer steers the CO 2 RR intermediates coverage by enhancing *OCHO intermediate stabilization and weakening *H binding. This innovative catalyst has been effectively utilized in acidic CO 2 electrolysis, attaining a maximum HCOOH Faradaic efficiency (FE) of 99% and a remarkable partial current density of 865 mA cm −2 at 1 A cm −2 , particularly achieving extraordinary stability – sustain FE exceeding 94% for 500 hours in strongly acidic media. This work opens up new opportunities of ultrastable implanting‐structured catalyst for long‐lasting acidic CO 2 electrolysis and other catalytic systems.