Polarized Ni0-Niδ+ Catalysts Enable Asymmetric C–C Coupling for Long-Chain Hydrocarbons in Electrochemical CO2 Reduction

Abstract

The efficient electrochemical CO₂ reduction reaction (CO₂RR) to long-chain hydrocarbons (C₃₊) still remains a formidable task even on the widely investigated copper-based catalysts. Recently, nickel-based catalysts have garnered wide attention for their promising ability to generate C₃₊ products. The design of Ni⁰-Ni^δ+ domains, analogous to the renowned Cu⁰-Cu^δ+ strategy, stands out as a hallmark approach, achieving substantial yields of C₃–C₆ compounds. However, theoretical understanding remains significantly limited. Here, we employ full-solvent ab initio molecular dynamics simulations with a slow-growth approach to investigate Ni⁰-Ni^δ+-mediated C–C coupling at partially polarized nickel. In this system, the nonpolarized region is constantly covered by the generated *CO, while the polarized domain─through strategic modulation of Ni’s d-band center─mitigates the poisoning effects of *CO₂ and *CO, thereby enhancing their activation. This facilitates C–C coupling primarily between *COOH and *CH_x(x = 1, 2), with significantly lower kinetic barriers compared to conventional *CO-involved pathways, laying the foundation for sustained carbon chain growth. Extending this concept to other metals (M = Fe, Rh, Pd, Co and Ru) with similar adsorption characteristics akin to Ni further underscores the potential of M⁰-M^δ+ domains for CO₂ electroreduction. Our study elucidates the microscopic mechanisms by which polarization strategies promote the formation of long-chain products, providing an original perspective for designing CO₂ electroreduction catalysts.