Recently, metal–organic frameworks (MOFs) have been receiving increasing attention because their modular building blocks give them diversity and functional adjustability. MOFs have achieved excellent results as novel proton-conducting materials. However, there are relatively limited studies on the properties of proton-conducting MOFs that can be regulated by changing the test environment. Herein we explored the proton conductivity of a ZnII MOF {[Zn3(m-MOD)2(H2O)6]·4H2O}n (ZS-1) (m-MOD = 2-(3-methoxy phenyl)-1H-imidazole-4,5-dicarboxylicacid) at humidity and aquaammonia vapor. ZS-1 has a 3D structure in the shape of a windmill, which contains hexagonal one-dimensional channels and a large number of free and coordination water molecules, providing convenient conditions for proton conduction. ZS-1 obtained an optimal conductivity of 1.38 × 10−3 S cm−1 (100 °C) under 2 M aquaammonia vapor, which was about three orders of magnitude higher than the maximum conductivity under water vapor (5.31 × 10−6 S cm−1, 100 °C-98% RH). The proton conduction mechanism is discussed in depth by combining the structural characteristics and related characterizations.
