Fig. 5: Surface states of Fe-Ni-Nx-C at the common potentials of HER (0 V), OER (1.60 V), ORR (0.78 V), CO2RR (−0.35 V), and NRR (−0.4 V).
From: Surface states of dual-atom catalysts should be considered for analysis of electrocatalytic activity
Groups 1–5, respectively, indicate the number of coordinating N: 0–1, 2, 3, 4, and 5–6. The pink vertical lines represent the electrochemical potential window (EPW) of DACs and various symbols filled with different colors represent different occupying species. In detail, we employed the red upper triangle, orange lower triangle, purple diamond, cyan square, indigo circle, and pink star to describe DACs will be covered by 2O*, 1O*, 1OH*, pristine, 2H*, and 1H*, respectively, at the operating potentials.
