Facet-Dependent Selectivity of Cu Catalysts in Electrochemical CO2 Reduction at Commercially Viable Current Densities

• Published in: ACS catalysis Vol. 10; no. 9; pp. 4854 - 4862
• Main Authors: De Gregorio, Gian Luca, Burdyny, Thomas, Loiudice, Anna, Iyengar, Pranit, Smith, Wilson A, Buonsanti, Raffaella
• Format: Journal Article
• Language: English
• Published: American Chemical Society 01-05-2020
• Subjects: gas-diffusion electrolyzer; nanocatalyst; copper; electrochemical CO2 reduction; structural selectivity
• ISSN: 2155-5435; 2155-5435
• DOI: 10.1021/acscatal.0c00297

Despite substantial progress in the electrochemical conversion of CO2 into value-added chemicals, the translation of fundamental studies into commercially relevant conditions requires additional efforts. Here, we study the catalytic properties of tailored Cu nanocatalysts under commercially relevant current densities in a gas-fed flow cell. We demonstrate that their facet-dependent selectivity is retained in this device configuration with the advantage of further suppressing hydrogen production and increasing the faradaic efficiencies toward the CO2 reduction products compared to a conventional H-cell. The combined catalyst and system effects result in state-of-the art product selectivity at high current densities (in the range 100–300 mA/cm2) and at relatively low applied potential (as low as −0.65 V vs RHE). Cu cubes reach an ethylene selectivity of up to 57% with a corresponding mass activity of 700 mA/mg, and Cu octahedra reach a methane selectivity of up to 51% with a corresponding mass activity of 1.45 A/mg in 1 M KOH.