Alternating Magnetic Field Induced Ultra‐Active Cu Sites in Trimetal‐Organic Frameworks for Low‐Overpotential CO ₂ Electroreduction

Abstract The electrochemical CO 2 reduction reaction is a sustainable approach to address climate challenges, requiring energy‐economic catalysts that are highly active at low electrode potentials. Herein, we developed a Cu‐ZnMg ultrathin metal‐organic framework (MOF), where Zn/Mg atoms enhance CO 2 adsorption and CO desorption and the Cu sites show ultrahigh catalytic activity from CO 2 ‐to‐CO electroreduction under an alternating magnetic field (AMF). The Cu‐ZnMg MOF@AMF exhibited a high current density (25.3 mA cm −2 ) at a low potential of −0.2 V versus RHE with remarkable CO selectivity (∼95%), surpassing that of state‐of‐the‐art Cu‐based catalysts. The incorporation of nonmagnetic metals isolates the unpaired electrons at Cu(II) active sites which are antiferromagnetically coupled in the 1D Cu(II) chains. These spin magnetic moments can effectively interact with the AMF through spin‐lattice relaxation, leading to local electronic energy elevation at the Cu sites. This AMF‐induced activation of isolated Cu sites promotes cooperative proton‐electron transfer, thereby enabling efficient from CO 2 ‐to‐CO conversion at low electrode potential.