Highly Efficient CO ₂ Electroreduction in Artificial Seawater Electrolyte Catalyzed by Strong‐Acid/Base‐Resistant MOF

Abstract

Abstract NaCl, a primary component of seawater, is a cost‐effective alternative electrolyte for CO 2 electroreduction; however, suppressing competitive hydrogen evolution reaction (HER) remains a challenge for efficient CO 2 RR. Herein, a novel Zn‐MOF {[Zn 5 (tz) 6 (HCOO) 4 ]·2H 2 O} n ( 1 , Htz = 1,2,3‐triazole) was prepared, exhibiting excellent stability in 0.5 M NaCl electrolyte for 16 weeks. 1 could maintain crystalline structure even after exposure to 9 M HCl and 2 M NaOH solutions. 1 achieved high selectivity for the electroreduction of CO 2 to CO with a maximum faradaic efficiency (FE CO ) of 94.4% under −1.5 V in artificial seawater electrolyte and 91.1% FE CO in treated natural seawater under −0.8 V, maintaining performance over 20 h. The mechanism analysis demonstrated that micropores in 1 could anchor coordinated H 2 O in [Na(H 2 O) 5 ] + to form a cationic layer at the particle surface, inhibiting the competitive HER and enhancing catalytic activity. Moreover, 1 could be applied in hectogram‐scale production with low cost of US$ 0.01405 g −1 , showing promising industrial potential in CO 2 RR. This work addresses a critical challenge of the strongly competitive HER in Na‐based electrolytes during electrochemical CO 2 RR, offering a feasible strategy for designing stable, efficient, and economical catalysts for sustainable energy applications.