fig5

Figure 5. (A) Free energy profiles and corresponding intermediate structures on V₂@g-C₃N₄ andNi₂@g-C₃N₄, Color scheme: H, white; C, gray; N, blue; V, red; Ni, pink. Reprinted with permission from Ref.^[93]. Copyright © 2022 Wiley-VCH GmbH; (B) N≡N bond lengths with and without H^* generated on the X site and the relationship between $$ \Delta G_{H^{\ast}} $$ and $$ E_{NNH^{\ast}}^a $$ on X/Fe-N-C (X = Pd, Ir, Pt), with an inset showing the schematic diagram of the cleavage of X−H bond to form NNH^*. Reprinted with permission from Ref.^[94]. Copyright © 2023 Wiley-VCH GmbH.