Ordered Hierarchical Ni‐N ₄ Carbon Microreactors Enable Localized CO Feeding to Copper for High‐Rate CO ₂ Electroreduction

Electrocatalytic CO 2 to produce multicarbon products (C 2+ ) by Cu‐based catalysts has long been hindered at high current densities, due to the sluggish mass transport at the electrolyte and catalyst interface. Herein, an ordered hierarchical porous carbon microreactor hosting atomically dispersed Ni sites is rationally designed, enabling outstanding CO 2 penetration and interfacial * CO supply with CO Faradaic efficiency (FE CO ) up to 93.1% over 100 h. Coupling with Cu nanoclusters, the tandem catalyst allows fast CO 2 to CO conversion and CO delivery to Cu interfaces, where localized C‐C coupling and subsequent reduction are promoted, thereby accelerating C 2+ product production. As a result, the as‐made catalyst demonstrates C 2+ product FE (FE C2+ ) up to 73.5% at a high current density of 800 mA cm −2 with a production rate up to 1.93 mmol h −1 cm −2 , which are all much higher than those for bare Cu (FE C2+ : 44.3%; rate: 1.23 mmol h −1 cm −2 ). In situ experiments and theoretical calculations indicate that abundant * CO supply and reduced energy barrier for hydrogenation and C‐C coupling synergistically upgrade intermediate CO to C 2+ products. This work provides a general approach to alleviate the high‐speed mass transportation limitations between electrolyte and catalyst, and eventually boosts efficient C 2+ production from CO 2 at high current density.