▎ 摘　　要

Coupled electron-proton transfer dominates the activity and selectivity of electrochemical CO2 reduction (CO2RR), still the concern on proton-feeding is far from satisfied especially in nitrogen-doped carbonaceous catalysts. Here, we report that pyridinic N cooperated with electron-donating BC3 provides with strengthened Lewis basicity for favorably electrophilic attack of CO2 and beneficial electron transfer, while implanted BC3 trigger water activation for availably proton-feeding, conducting to superior CO production rate on two-step synthesized B and N co-doped porous graphene (tBNPG) over single N-doped reference. Inspired by such cognition, oxygen-containing groups applauded by their charge induced effect, were further decorated on tBNPG but elevating the competitive H2 evolution (HER). Mechanistic studies illustrate that lateral oxygen function-alities, especially -COOH, deliver BC3 sites much lower limiting potentials for H2O transition to *H, determining whose fate branches to HER versus CO2RR. The atomic-level insight paves the cornerstone for the catalysts design of proton-involved electrochemical reactions.