Fig. 4. (a) Schematic depiction of the CO₂ reduction pathways toward a variety of C1 products (CO, HCOOH, HCHO, CH₃OH and CH₄) on M₁M₂/C₂N (M₁M₂ = CuCr, CuMn, FeCr, and MnCr). (b) Thermodynamic limiting potentials toward C1 products (CO, HCOOH, HCHO, CH₃OH and CH₄) on CuCr/C₂N, CuMn/C₂N, FeCr/C₂N, and MnCr/C₂N.