Synergistic Effect of Atomically Dispersed Ni–Zn Pair Sites for Enhanced CO₂ Electroreduction

Abstract

Dual‐atom catalysts have the potential to outperform the well‐established single‐atom catalysts for the electrochemical conversion of CO2. However, the lack of understanding regarding the mechanism of this enhanced catalytic process prevents the rational design of high‐performance catalysts. Herein, an obvious synergistic effect in atomically dispersed Ni–Zn bimetal sites is observed. In situ characterization combined with density functional theory (DFT) calculations reveals that heteronuclear coordination modifies the d‐states of the metal atom, narrowing the gap between the d‐band centre (εd) of the Ni (3d) orbitals and the Fermi energy level (EF) to strengthen the electronic interaction at the reaction interface, resulting in a lower free energy barrier (ΔG) in the thermodynamic pathway and a reduced activation energy (Ea) as well as fortified metal–C bonding in the kinetic pathway. Consequently, a CO faradaic efficiency of >90% is obtained across a broad potential window from −0.5 to −1.0 V (vs RHE), reaching a maximum of 99% at −0.8 V, superior to that of the Ni/Zn single‐metal sites.

Atomic Bridging Structure of Nickel–Nitrogen–Carbon for Highly Efficient Electrocatalytic Reduction of CO2

“…Chemie significant electron delocalization suggest the easy adsorption of carbon dioxide. [24] Thus, the presence of NiÀ Ni bridging coordination can effectively modulate the electronic structure for optimal adsorption and activation of CO 2 . These results validate that Ni 2 À N 4 À C 2 with unique atomic bridging features promotes the favorable reduction of CO 2 into CO.…”

Mechanistic understanding and design of non-noble metal-based single-atom catalysts supported on two-dimensional materials for CO2 electroreduction

“…5d. 117 The calculated free energy of *COOH revealed a reduced barrier on the Ni–Zn bimetallic SACs (Fig. 5e).…”

“…116 The latest reported work involved the study of atomically dispersed Ni–Zn catalysts with an M 1 M 2 –N 6 –C structure from both kinetical and thermodynamic perspectives. 117 In terms of kinetics, the authors utilized the climbing image nudged elastic band (CI-NEB) calculation to study the reaction process, with the starting, intermediate, and final states, as depicted in Fig. 5d.…”

Low‐dimensional material supported single‐atom catalysts for electrochemical CO2 reduction

“…In addition to homonuclear DMS catalysts mentioned above, the fabrication of heteronuclear DMS catalysts is also conductive to enhance the ECR performance. Up to now, heteronuclear DMS Ni/Co, 151 Zn/Co, 152 Ni/Zn, 153 Ni/Cu, 154 NiSn, 155 Ni/Fe, 148,156,157 Fe/Cu, 158 and Zn/Ln 159 catalysts have been demonstrated to be effective ECR. For example, Zhao et al 148 synthesized a catalyst with Ni–Fe DMS anchored on NC for ECR.…”