Screening of Various Catalysts for Electrochemical CO ₂ Reduction at Elevated Temperatures and Pressures

Traditionally, catalysts for the electrochemical CO 2 reduction reaction (CO2RR) have been categorized in four groups: producing either mainly H 2 , CO, HCOOH, or C2+ products. However, this categorization is based on experiments at ambient conditions. Using a high‐pressure, high‐temperature electrochemical cell, herein, CO 2 reduction is performed at vastly different conditions. Twenty metal catalysts have been screened for their ability to perform CO 2 reduction at conditions up to 30 bar and 100 °C at 1.5 V versus SHE in aqueous electrolyte. It is shown that at this potential, catalysts which have average activity at ambient conditions can reach near 100% efficiency for CO2RR at 30 bar and maintain this high efficiency at high temperatures. Both temperature and pressure can increase the CO2RR activity significantly. However, if a catalyst does not perform CO2RR at ambient conditions, increasing pressure and temperature will only increase CO2RR selectivity by up to a maximum of 30%. Nevertheless, some of these inferior CO2RR catalysts at room temperature do show interesting products beyond CO and HCOOH at higher pressure and temperature, such as long‐chain hydrocarbons and methanol.