Switching CO Electroreduction Pathway to n -Propanol by Pulsed Electrolysis

The electrochemical CO 2 or CO reduction reaction by copper-based catalysts features an attractive approach to generate value-added products. However, the selectivity of C 3+ products (such as n -propanol) is still substantially limited due to the sluggish kinetics of C 2 –C 1 coupling at the critical bifurcation point of the C 2 intermediate (CH 3 –CHO*) compared to its competing hydrogenation toward ethanol formation. In this work, we have demonstrated a pulsed electrolysis strategy for CO-to-C 3 electroreduction using a conventional CuO-derived Cu catalyst. The half cycles with more positive (or less negative) potentials allow a decrease in the *H coverage and the electrochemical hydrogenation of CH 3 –CHO* intermediates, thus inhibiting the ethanol formation pathway. Meanwhile, the nonredox coupling of CH 3 –CHO* with *CO is promoted to form the C 3 intermediates, which are further electrochemically reduced to n -propanol during the next negative half cycles. Under an optimal pulsed electrolysis condition, this conventional CuO-derived Cu catalyst exhibited a CO-to- n -propanol Faradaic efficiency of 31% and a corresponding n -propanol partial current density of 27.7 mA·cm –2, substantially exceeding the same Cu catalyst under the constant potentiostatic condition, thus featuring a useful means of switching CO electroreduction selectivity from ethanol to n -propanol at the CH 3 –CHO* bifurcation point.