Fig. 4: Structure and proton transport behaviors of m-HSbP2O8 membranes.
From: Significant enhancement of proton conductivity in solid acid at the monolayer limit
a–c The structure models of HSbP2O8 bulk (a) and monolayer along in plane (b) and cross-sectional (c) direction, where the oxygen atoms are omitted for clarity, and the protons trapped on the bridging oxygen atoms of P-O-Sb are marked in red. d AFM image of m-HSbP2O8 nanosheets, showing a thickness of ~1 nm. e, f Photograph (e) and the cross-sectional SEM image (f) of a free-standing m-HSbP2O8 membrane. The “IMR” LOGO in (e) is used with permission from the Institute of Metal Research, Chinese Academy of Sciences. g The XRD pattern of m-HSbP2O8 membrane at 100% RH. Inset showing the wettability of m-HSbP2O8 membrane toward the water. h Comparison of proton conductivities of m-HSbP2O8 membranes and HSbP2O8 bulk at different temperatures and 70% RH. Dashed lines are guides for the eye. i Temperature dependence of the proton conductivities and the corresponding Arrhenius plot (inset) of m-HSbP2O8 membranes at 100% RH. Error bars represent standard deviations.
