Gas-Phase Electrocatalytic CO₂ Reduction on Pd-Embedded UiO-67 Metal-Organic Framework Precatalysts Under Varying...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Electrocatalytic CO2 reduction (ECO2R) offers a pathway for CO2 utilization, converting waste CO2 into valuable chemicals.
• Catalyst design and cell configuration are critical for ECO2R efficiency, selectivity, and reaction pathways.

Purpose of the Study:

• To investigate the role of Zr- and Ce-based UiO-67 metal-organic frameworks (MOFs) containing palladium species in ECO2R.
• To explore the influence of water content (relative humidity) on product selectivity in a zero-gap gas diffusion cathode.
• To understand the in-situ transformation of MOFs into active electrocatalysts.

Main Methods:

• Utilized isotopological Zr- and Ce-based UiO-67 MOFs with embedded Pd species.
• Employed a zero-gap gas diffusion cathode electrode configuration.
• Varied the relative humidity (RH) of the CO2 gas stream during electrocatalysis.

Main Results:

• UiO-67 MOFs containing embedded Pd were found to produce syngas (CO and H2) via ECO2R.
• Product selectivity was controllable by adjusting the RH levels in the CO2 feed.
• Pristine MOFs transformed into active catalysts during the ECO2R reaction.

Conclusions:

• Water content significantly impacts selectivity in ECO2R reactions.
• Pd-embedded MOFs show promise as active catalysts for CO2 electroreduction to syngas.
• Predictive catalyst design is essential for advancing CO2 electroreduction to high-value chemicals.