Capture and electroreduction of CO2 using highly efficient bimetallic Pd-Ag aerogels paired with carbon nanotubes

The rational design of efficient catalysts for electrochemical CO2 reduction is a critical step towards achieving industry-ready electrolyzer systems. Noble metal aerogels have emerged as state-of-the-art catalysts that play a crucial role in several applications. Here, we report bimetallic PdxAgy aerogels that have been optimized by modulating the Pd/Ag ratio for the capture and selective electroreduction of CO2. Pd0.67Ag0.33 exhibited the greatest ability to reduce CO2 to CO with faradaic efficiency (FE): 84% and current density (j): -23 mA cm(-2) at -0.8 V vs. RHE in 0.1 M NaHCO3. Using a carbon nanotube solid support (Pd0.67Ag0.33/CNT), we could further enhance the FE to 91% with a higher current density of -38 mA cm(-2) at lower overpotential (-0.7 V vs. RHE). This remarkable catalytic activity is higher than that of monometallic Pd (FE: 43%, j: -3.4 mA cm(-2)) and Ag (FE: 68%, j: -2.6 mA cm(-2)) aerogels at -0.8 V vs. RHE. Using bimetallic aerogels provides an effective strategy that could inspire the design of new catalysts for a variety of applications.