Abstract: Single- and dual-atom catalysts (SACs and DACs) on single-layer graphene are widely investigated for a wide range of electrochemical reactions. However, the effect of van der Waals interactions on the activity of these catalysts has not been investigated through systematic high-throughput screening. Here we introduce the concept of van der Waals interactions through a double-layer DAC structure which has axial d orbital modification towards enhanced CO₂ reduction reaction (CO₂RR), hydrogen evolution reaction (HER), oxygen reduction reaction (ORR), and oxygen evolution reaction (OER). We applied density functional theory (DFT) to screen 3d, 4d, and 5d transition metals supported by double-layer nitrogen-doped graphene, denoted as M2N8. We sought catalysts with high thermodynamic and electrochemical stabilities along with low overpotentials for CO₂RR, ORR, OER, or HER. We find that HER can take place inside the van der Waals gap of V2N8 and Co2N8 leading to overpotentials of 0.10 and 0.16 V. Moreover, ORR and OER can take place on the surface of Fe2N8 and Ir2N8, respectively, leading to overpotentials of 0.39 and 0.37 V. DFT predicts a CO₂RR overpotential of 0.85 V towards CO on the surface of Co2N8 along with the HER overpotential of 0.16 V inside the van der Waals gap of Co2N8 towards the production of syngas (CO+H₂). This paper provides fundamental insights into the design of advanced multi-layer catalysts by applying the concept of van der Waals interactions for electrochemistry at room temperature.

Key words: ORR, OER, HER, CO₂RR, CO₂ capture, syngas, double-layer