Nanosheet Superhydrophobic Porous Coordination Polymers (NSPCPs) for Distinctive Electrochemical Water Splitting

We achieved three nanosheet superhydrophobic porous coordination polymers (NSPCPs), [Zn 4 (mu 3 -OH) 2 (BTMB) 2 ], (PESD-1@nanosheet), and [Zn 2 M 2 (mu 3 -OH) 2 (BTMB) 2 ], (PESD-2 and 3@nanosheets) (M = Co and Ni), by the chemical exfoliation method. The formation of these three NSPCPs was confirmed by PXRD, SEM, TEM, EDAX, etc. The contact angles of PESD-1, 2, and 3@nanosheets are 157.9, 164.1, and 162.4 degrees, respectively, which enhanced the hydrophobicity due to the high surface area compared to that of bulk PESD-1, 2, and 3 (155.5, 159.3, and 160.8 degrees, respectively). Moreover, in this study, we also report a unique and first study of electrochemical water splitting by superhydrophobic materials, in contrast to hydrophobic surfaces, which usually do not involve catalytical splitting of water. These three PESD-1, 2, and 3@nanosheets exhibit hydrogen evolution reactions (HERs) with overpotentials of 1157, 728, and 835 mV and oxygen evolution reactions (OERs) with overpotentials of 1450, 550, and 1070 at 10 mA cm-2 in alkaline electrolytes, respectively. Furthermore, they also exhibit good catalytical stability for more than 26 h, which indicates the good recyclability of the catalysts.