Abstract:
:Direct conversion of carbon dioxide to multicarbon products remains as a grand challenge in electrochemical CO2 reduction. Various forms of oxidized copper have been demonstrated as electrocatalysts that still require large overpotentials. Here, we show that an ensemble of Cu nanoparticles (NPs) enables selective formation of C2-C3 products at low overpotentials. Densely packed Cu NP ensembles underwent structural transformation during electrolysis into electrocatalytically active cube-like particles intermixed with smaller nanoparticles. Ethylene, ethanol, and n-propanol are the major C2-C3 products with onset potential at -0.53 V (vs. reversible hydrogen electrode, RHE) and C2-C3 faradaic efficiency (FE) reaching 50% at only -0.75 V. Thus, the catalyst exhibits selective generation of C2-C3 hydrocarbons and oxygenates at considerably lowered overpotentials in neutral pH aqueous media. In addition, this approach suggests new opportunities in realizing multicarbon product formation from CO2, where the majority of efforts has been to use oxidized copper-based materials. Robust catalytic performance is demonstrated by 10 h of stable operation with C2-C3 current density 10 mA/cm2 (at -0.75 V), rendering it attractive for solar-to-fuel applications. Tafel analysis suggests reductive CO coupling as a rate determining step for C2 products, while n-propanol (C3) production seems to have a discrete pathway.
journal_name
Proc Natl Acad Sci U S Aauthors
Kim D,Kley CS,Li Y,Yang Pdoi
10.1073/pnas.1711493114subject
Has Abstractpub_date
2017-10-03 00:00:00pages
10560-10565issue
40eissn
0027-8424issn
1091-6490pii
1711493114journal_volume
114pub_type
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