Insight into the role of oxygen-containing groups in the proton conductivity of graphdiyne oxides

The role of oxygen-containing groups in the proton conductivity of carbon materials is still a blind area although it is of great importance in the development of proton conductors with ultrahigh proton conductivity. Here, we for the first time investigate the essential role of oxygen-containing groups in the proton conductivity of graphdiyne oxides (GDYO). GDYO with similar O/C ratios but different contents of various oxygen-containing groups were prepared and used for investigations. The results demonstrate that each type of oxygen-containing group has a distinctive role in proton conduction, showing different influences towards the proton conductivity of GDYO. Specifically, C-O-C and C00000000000000000000000000000000111111110000000011111111000000000000000000000000O play key roles in facilitating fast proton propagation, which determines the exchange rate of protons between two active sites. OC-OH and C-OH are essential for water adsorption, which dominate the formation of proton transport pathways and influence proton concentration. This work not only reveals the roles of oxygen-containing groups on proton conductivity but also paves a new avenue in the design of proton conductors with advanced performances. This study demonstrated that C-O-C and CO play key roles in facilitating fast proton propagation, while OC-OH and C-OH are essential for proton concentration.