@article{a12866c377a84fde8c8d83cbd6d58ccb,
title = "Highly active oxygen evolution integrated with efficient CO2 to CO electroreduction",
abstract = "Electrochemical reduction of CO2 to useful chemicals has been actively pursued for closing the carbon cycle and preventing further deterioration of the environment/climate. Since CO2 reduction reaction (CO2RR) at a cathode is always paired with the oxygen evolution reaction (OER) at an anode, the overall efficiency of electrical energy to chemical fuel conversion must consider the large energy barrier and sluggish kinetics of OER, especially in widely used electrolytes, such as the pH-neutral CO2-saturated 0.5 M KHCO3. OER in such electrolytes mostly relies on noble metal (Ir- and Ru-based) electrocatalysts in the anode. Here, we discover that by anodizing a metallic Ni–Fe composite foam under a harsh condition (in a low-concentration 0.1 M KHCO3 solution at 85 °C under a high-current ∼250 mA/cm2), OER on the NiFe foam is accompanied by anodic etching, and the surface layer evolves into a nickel–iron hydroxide carbonate (NiFe-HC) material composed of porous, poorly crystalline flakes of flower-like NiFe layer-double hydroxide (LDH) intercalated with carbonate anions. The resulting NiFe-HC electrode in CO2-saturated 0.5 M KHCO3 exhibited OER activity superior to IrO2, with an overpotential of 450 and 590 mV to reach 10 and 250 mA/cm2, respectively, and high stability for >120 h without decay. We paired NiFe-HC with a CO2RR catalyst of cobalt phthalocyanine/carbon nanotube (CoPc/CNT) in a CO2 electrolyzer, achieving selective cathodic conversion of CO2 to CO with >97% Faradaic efficiency and simultaneous anodic water oxidation to O2. The device showed a low cell voltage of 2.13 V and high electricity-to-chemical fuel efficiency of 59% at a current density of 10 mA/cm2 ",
keywords = "CO electrolyzer, CO reduction, Electrocatalysis, Oxygen evolution, PH-neutral electrolyte",
author = "Yongtao Meng and Xiao Zhang and Hung, {Wei Hsuan} and Junkai He and Tsai, {Yi Sheng} and Yun Kuang and Kenney, {Michael J.} and Shyue, {Jing Jong} and Yijin Liu and Stone, {Kevin H.} and Xueli Zheng and Suib, {Steven L.} and Lin, {Meng Chang} and Yongye Liang and Hongjie Dai",
note = "Funding Information: ACKNOWLEDGMENTS. W.-H.H. was supported by Ministry of Science and Technology, Taiwan, Grant MOST-106-2918-I-035-002. Y.M. thanks Dr. Kai Zhou from University of Connecticut for the assistance of theoretical simulation. Funding Information: W.-H.H. was supported by Ministry of Science and Technology, Taiwan, Grant MOST-106-2918-I-035-002. Y.M. thanks Dr. Kai Zhou from University of Connecticut for the assistance of theoretical simulation. Funding Information: aCollege of Electrical Engineering and Automation, Shandong University of Science and Technology, 266590 Qingdao, China; bDepartment of Chemistry, Stanford University, Stanford, CA 94305; cDepartment of Materials Science and Engineering, South University of Science and Technology of China, 518055 Shenzhen, China; dInstitute of Materials Science and Engineering, National Central University, 32001 Taoyuan, Taiwan; eInstitute of Materials Science, University of Connecticut, Storrs, CT 06269; fResearch Center of Applied Science, Academia Sinica, 115 Taipei, Taiwan; gStanford Synchrotron Radiation Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA 94025; and hDepartment of Material Science and Engineering, Stanford University, Stanford, CA 94305 Publisher Copyright: {\textcopyright} 2019 National Academy of Sciences. All rights reserved.",
year = "2019",
month = nov,
day = "26",
doi = "10.1073/pnas.1915319116",
language = "English",
volume = "116",
pages = "23915--23922",
journal = "Proceedings of the National Academy of Sciences of the United States of America",
issn = "0027-8424",
publisher = "National Academy of Sciences",
number = "48",
}
