Selective CO₂-to-HCOOH Electroreduction on Graphdiyne-Supported Bimetallic Single-Cluster Catalysts

The oxophilic elements may stabilize the O-intermediate in electrochemical CO2 reduction reaction (eCO2RR), yet their applications for formic acid (HCOOH) production may be limited by the Sabatier principle. Here we explore the bimetallic M1Ti3 (M = Ni, Pd, Pt, Cu, Ag, Au) single-cluster catalysts (SCCs) anchored on graphdiyne (GDY) for eCO2RR to produce HCOOH. First-principles calculations show that the M1Ti3/GDY SCCs prefer to activate and hydrogenate CO2 to the *OCHO intermediate (*denotes the active site of the catalyst) due to the oxophilic Ti sites, while the M1 site plays a key role in suppressing the adsorption of *H and tuning the adsorption of *OCHO and *HCOOH for the HCOOH production, which is attributed to the modulation of Ti–O bonding strength by the M1 atom. We predict that the Au1Ti3/GDY SCC is an efficient electrocatalyst for the selective eCO2RR to produce HCOOH. The directions for further improvements for the selective eCO2RR to produce HCOOH are discussed.