US EPA

5020560 

Journal Article 

Promoter Effects of Functional Groups of Hydroxide-Conductive Membranes on Advanced CO2 Electroreduction to Formate 

Wang, M; Preston, N; Xu, N; Wei, Y; Liu, Y; Qiao, J 

2019 

1 

ACS Applied Materials & Interfaces
ISSN: 1944-8244
EISSN: 1944-8252 

AMER CHEMICAL SOC 

WASHINGTON 

11 

7 

6881-6889 

English 

30676728 

10.1021/acsami.8b11845 

WOS:000459642200020 

http://://WOS:000459642200020
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The electrochemical reduction of CO2 at ambient conditions provides a latent solution of turning waste greenhouse gases into commodity chemicals or fuels; however, a satisfactory ion-conducting membrane for maximizing the performance of a CO2 electrolyzer has not been developed. Here, we report the synthesis of a sequence of hydroxide-conductive polymer membranes, which are based on polymer composites of poly(vinyl alcohol)/Guar hydroxypropyltrimonium chloride, for use in CO2 electrolysis. The effect of different membrane functional groups, including thiophene, hydroxybenzyl, and dimethyloctanal, on the efficiency and selectivity of CO2 electroreduction to formate is thoroughly evaluated. The membrane incorporating thiophene groups exhibits the highest Faradaic efficiency of 71.5% at an applied potential of -1.64 V versus saturated calomel electrode (SCE) for formate. In comparison, membranes containing hydroxybenzyl and dimethyloctanal groups produced lower efficiencies of 67.6 and 68.6%, respectively, whereas the commercial Nafion 212 membrane was only 57.6% efficient. The improved efficiency and selectivity of membranes containing thiophene groups are attributed to a significantly increased hydroxide conductivity (0.105 S cm-1), excellent physicochemical properties, and the simultaneous attenuation of formate product crossover. 

formate production; binary cross-linking; functional group; electroreduction; alkaline anion-exchange membrane; solid polymer electrolyte; anion-exchange membranes; cationic guar gum; electrochemical reduction; carbon-dioxide; poly(vinyl alcohol); formic-acid; composite; Science & Technology - Other Topics; Materials Science