Copper-Based Metal-Organic Porous Materials for CO2 Electrocatalytic Reduction to Alcohols

The electrocatalytic reduction of CO2 has been investigated using four Cu-based metal-organic porous materials supported on gas diffusion electrodes, namely, (1) HKUST-1 metal-organic framework (MOF), [Cu-3(mu(6)-C9H3O6)(2)](n); (2) CuAdeAce MOF, [Cu-3(mu 3-C5H4N5)(2)](n); (3) CuDTA mesoporous metal-organic aerogel (MOA), [Cu(mu-C2H2N2S2)](n); and (4) CuZnDTA MOA, [Cu0.6Zn0.4(mu-C2H2N2S2)](n). The electrodes show relatively high surface areas, accessibilities, and exposure of the Cu catalytic centers as well as favorable electrocatalytic CO2 reduction performance, that is, they have a high efficiency for the production of methanol and ethanol in the liquid phase. The maximum cumulative Faradaic efficiencies for CO2 conversion at HKUST-1-, CuAdeAce-, CuDTA-, and CuZnDTA-based electrodes are 15.9, 1.2, 6, and 9.9 %, respectively, at a current density of 10 mAcm(-2), an electrolyte-flow/area ratio of 3 mLmincm(-2), and a gas-flow/area ratio of 20 mLmincm(-2). We can correlate these observations with the structural features of the electrodes. Furthermore, HKUST-1- and CuZnDTA-based electrodes show stable electrocatalytic performance for 17 and 12 h, respectively.