Ultrathin proton exchange membranes with enhanced dimensional stability towards acidic CO 2 electroreduction

Abstract

An ultrathin proton exchange membrane was prepared by embedding MIL-110 nanoneddle skeletons into SPEEK membranes. The hydrid membrane showed enhanced dimensional stability and mechnical prpertiy, as well as regualted proton conductivity of 9.6×10 -3 S cm -1 . When applied into acidic CO2 electroreduction, it favored for CO2 conversion and suppressing HER.Electrochemical CO2 reduction is a promising technique to form value-added chemicals and meet the goal of carbon neutrality. [1][2][3] Recent efforts have focused on achieving target products, such as C2+ products, in the alkaline or neutral condition. [4][5][6] But the CO2 electrolysis in alkaline or neutral electrolytes faced the challenge of formation of insoluble carbonates, which will decrease the CO2 utilization and block mass transfer channels of the gas diffusion electrode. [7][8][9][10] Electrochemical CO2 reduction in the acidic electrolyte could inhibit the formation of carbonates effectively. [11][12][13] Therefore, acidic CO2 electrolysis draws more and more attentions recently. But the competitive HER leads to the low efficiency for CO2 conversion, since protons are more favourable to be reduced than CO2. [14][15][16][17]