Breaking Scaling Relations for Highly Efficient Electroreduction of CO2 to CO on Atomically Dispersed Heteronuclear Dual‐Atom Catalyst

Conversion of CO2 into value‐added products by electrocatalysis provides a promising way to mitigate energy and environmental problems. However, it is greatly limited by the scaling relationship between the adsorption strength of intermediates. Herein, Mn and Ni single‐atom catalysts, homonuclear dual‐atom catalysts (DACs), and heteronuclear DACs are synthesized. Aberration‐corrected annular dark‐field scanning transmission electron microscopy (ADF‐STEM) and X‐ray absorption spectroscopy characterization uncovered the existence of the Mn─Ni pair in Mn─Ni DAC. X‐ray photoelectron spectroscopy and X‐ray absorption near‐edge spectroscopy reveal that Mn donated electrons to Ni atoms in Mn─Ni DAC. Consequently, Mn─Ni DAC displays the highest CO Faradaic efficiency of 98.7% at −0.7 V versus reversible hydrogen electrode (vs RHE) with CO partial current density of 16.8 mA cm−2. Density functional theory calculations disclose that the scaling relationship between the binding strength of intermediates is broken, resulting in superior performance for ECR to CO over Mn─Ni─NC catalyst. In this work, Ni SAC (Ni─NC), Mn SAC (Mn─NC), Ni─Ni DAC (Ni─Ni─NC), Mn─Mn DAC (Mn─Mn─NC), and Mn─Ni DAC (Mn─Ni─NC) are synthesized by a facile method. The catalyst with Mn─Ni atom pair exhibiting outstanding catalytic activity and selectivity, achieving a maximum FE(CO) of 98.7% at the potential of −0.7 V (vs RHE) with a CO partial current density of 16.8 mA cm−2. The study discloses that the highly efficient ECR to CO on heteronuclear DACs is attributed to the electron interaction of the Mn─Ni atom pair, which can break the scaling relationship of adsorption energies of intermediates.