Water-Mediated ElectroHydrogenation of CO2 at Near-Equilibrium Potential by Carbon Nanotubes/Cerium Dioxide Nanohybrids

Abstract

[Abstract]: The combination of multiwalled carbon nanotubes (MWCNTs) with undoped CeO2 na-noparticles (NPs) is effective for the direct electrocatalytic reduction of CO2 to formic acid (FA) at acidic pH (0.1 M HNO3), at overpotential as low as η = −0.02 V (vs RHE) with Faradic efficiency (FE) up to 65%. Exsitu and operando evidence identifies nons-toichiometric Ce4+/3+O2–x reduced sites as essential for the selective CO2 reduction reac-tion (CO2RR). The MWCNT-mediated electrochemical reduction of the CeO2 NPs of-fers a definite advantage with respect to the generally adopted thermochemical cycles (800–1500 °C) or deep hydrogenation pretreatments, thus presenting an interesting perspective for the engineering of CeO2 electrocatalysts.