A Metal–Organic Framework derived Cu_<i>x</i>O_yC_z Catalyst for Electrochemical CO₂ Reduction and Impact of Local pH Change

Abstract

Developing highly efficient and selective electrocatalysts for the CO₂ reduction reaction to produce value-added chemicals has been intensively pursued. We report a series of Cu_x O_y C_z nanostructured electrocatalysts derived from a Cu-based MOF as porous self-sacrificial template. Blending catalysts with polytetrafluoroethylene (PTFE) on gas diffusion electrodes (GDEs) suppressed the competitive hydrogen evolution reaction. 25 to 50 wt % teflonized GDEs exhibited a Faradaic efficiency of ≈54 % for C₂₊ products at -80 mA cm^-2 . The local OH^- ions activity of PTFE-modified GDEs was assessed by means of closely positioning a Pt-nanoelectrode. A substantial increase in the OH^- /H₂ O activity ratio due to the locally generated OH^- ions at increasing current densities was determined irrespective of the PTFE amount.