Graphyne/Electride Heterostructures Supporting Single-Atom Catalysts for Enhancing Electrocatalytic CO2 Reduction

Electrocatalytic carbon dioxide reduction (CO2RR) offers a promising route to high-value chemicals and sustainable energy conversion, but the performance of traditional single-atom catalysts (SACs) is constrained by inadequate electronic regulation from the support. To address this, we constructed a novel series of catalytic systems, designated TM@GY-Ca2N, consisting of transition metals (TM) embedded in γ-graphyne (GY) and supported by a Ca2N heterostructure. In this design, γ-graphyne stabilizes TM atoms and Ca2N electride modulates their electronic structure via interlayer electron transfer. Consequently, the specific TM center dictates the CO2RR pathway, enabling selective production of CH4, CO, HCOOH, or CH3OH. To understand these mechanisms, we established family-specific empirical descriptors─including the spin-polarized d-band centers, dz2 orbital centers, and ICOHP values for TM-C/O bonds─that correlate electronic structure with catalytic performance via linear regression. This work presents a novel heterostructure-controlled strategy for designing high-performance SACs for CO2RR and provides theoretical guidance for developing efficient carbon-neutral electrocatalysts.