Enhanced proton conductivity and overall water splitting efficiency of dye@MOF by post-modification of MOF

Herein, dye@MOF composite was prepared by the encapsulation of 8-hydroxy-1,3,6-pyrenetrisulfonic acid tri-sodium salt (HPTS) into the pores of metal-organic framework (MOF). Firstly, the proton conductivities (sigma) of MOF and dye@MOF were evaluated, the sigma value of dye@MOF is 10 times that of MOF at 100 degrees C, which indicates dye@MOF has excellent proton conduction capacity. Secondly, MOF and dye@MOF show excellent catalytic performances for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) under alkaline medium, that is, when the current density is 10 mA center dot cm(-2), the overpotentials of MOF and dye@MOF are 225 mV and 194 mV for OER, and 511 mV and 497 mV for HER, respectively. Moreover, an asymmetric electrolyzer of dye@MOF/nickel foam (NF)||dye@MOF/NF was assembled to assess the efficiency of dye@MOF for overall water splitting, the result shows that the current density of dye@MOF is 35 mA center dot cm(-2) at 1.98 V, which exceeds that of MOF-based electrode. The excellent catalytic activity and enhanced proton conductivity of dye@MOF is mainly attributed to encapsulating dye molecules into the channels of MOF. In view of superior catalytic activity and excellent stability, dye@MOF is expected to be a bifunctional electrocatalyst for HER and OER.