Stability of Product Generation During CO Reduction on Copper

Copper is one of the most effective catalysts for electrochemically reducing CO and CO2 to useful products. However, the copper surface changes during prolonged electrolysis. To better understand these changes and how they affect the reaction, we performed in situ differential electrochemical mass spectrometry and infrared spectroscopy to monitor the change in volatile products and adsorbates generated over the course of the reaction. During CO reduction at a copper electrode for a series of consecutive cyclic voltammograms (CVs), if the anodic potential limit of the CV does not oxidize the electrode (−0.3 V vs standard hydrogen electrode), in NaHCO3, methane generation initially decreases and multicarbon product (C2 products) generation initially increases. Periodically oxidizing the electrode surface by sweeping the electrode potential to 0.1 V causes surface roughening that decreases the generation of hydrogen over time but keeps the relative amounts of C1 and C2 the same. When the reaction is carried ...