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

Abstract

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 CO 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.