Theoretical insights on oxygen electrode reactions of YNxC4-x@Gra with hydroxylation effect.

• The bifunctional catalytic mechanisms of YN x C 4-x @Gra with hydroxylation effect were discussed for the first time. • Hydroxylation is beneficial for improving the catalytic activity of stable coordination configurations. • YN 2 C 2oppo /N 2 C 2pen /N 3 C 1 OH@Gra with the stable coordination environment exhibit excellent bifunctional activity. • The descriptor d-electron number was introduced to rapidly predict catalytic activity. The oxygen electrode reactions (ORR/OER) are the key to electrochemical storage and conversion technologies. In this study, the bifunctional electrocatalytic mechanisms of YN x C 4-x @Gra with hydroxylation effect were discussed extensively. Firstly, the configurations with N coordination have good stability. Secondly, YN 1 C 3 /N 2 C 2hex @Gra with unstable coordination environment break the scale relationships between adsorption intermediates and exhibit outstanding OER performance with ηOER of 0.45 V and 0.46 V. Thirdly, YN 2 C 2oppo /N 2 C 2pen /N 3 C 1 OH@Gra with stable coordination environment demonstrate excellent bifunctional activity with ηORR of 0.48 V, 0.54 V, and 0.53 V and ηOER of 0.71 V, 0.73 V, 0.63 V. Forth, for catalysts with stable coordination environments, there are scale relationships between the adsorption of intermediates, and thus volcanic curves were constructed. Finally, the d-electron number was introduced to predict catalytic performance, saving time and computative costs for screening potential catalyst configurations. All in all, YN x C 4-x @Gra catalysts are potential oxygen electrode bifunctional electrocatalysts. [Display omitted] [ABSTRACT FROM AUTHOR]