Confining Chainmail‐Bearing Ni Nanoparticles in N‐doped Carbon Nanotubes for Robust and Efficient Electroreduction of CO 2

It still remains challenging to simultaneously achieve high stability, selectivity, and activity in CO 2 reduction. Herein, a dual chainmail‐bearing nickel‐based catalyst (Ni@NC@NCNT) was fabricated via a solvothermal‐evaporation‐calcination approach. In situ encapsulated N‐doped carbon layers (NCs) and nanotubes (NCNTs) gave a dual protection to the metallic core. The confined space well maintained the local alkaline pH value and suppressed hydrogen evolution. Large surface area and abundant pyridinic N and Ni δ + sites ensured high CO 2 adsorption capacity and strength. Benefitting from these, it delivered a CO faradaic efficiency of 94.1 % and current density of 48.0 mA cm −2 at −0.75 and −1.10 V, respectively. Moreover, the performance remained unchanged after continuous electrolysis for 43 h, far exceeding Ni@NC with single chainmail, Ni@NC/NCNT with Ni@NC sitting on the walls of NCNT, bare NCNT and most state‐of‐the‐art catalysts, demonstrating structural superiority of Ni@NC@NCNT. This work sheds light on designing unique architectures to improve electrochemical performances.