Metal-Support Interactions in Single-Atom Catalysts for Electrochemical CO₂ Reduction

Area of Science:

• Catalysis
• Materials Science
• Electrochemistry

Background:

• Electrochemical CO2 reduction (CO2RR) offers a sustainable pathway for converting greenhouse gases into fuels and chemicals.
• Key challenges include sluggish CO2 activation, poor selectivity, and competition with hydrogen evolution.
• Single-atom catalysts (SACs) present a promising solution due to maximized metal utilization and tunable electronic structures.

Purpose of the Study:

• To review the role of single-atom catalyst supports in governing CO2RR intermediate adsorption and conversion.
• To emphasize selectivity descriptors and rational design strategies for directing CO2RR pathways.
• To discuss representative SAC systems and their performance under relevant conditions.

Main Methods:

• Review of literature on single-atom catalysts for CO2RR.
• Analysis of structure-property relationships in SAC supports (porosity, doping, vacancies).
• Discussion of selectivity descriptors (coordination number, d-band position, binding energies).

Main Results:

• SAC support features significantly influence CO2 adsorption and intermediate conversion, controlling product distribution (CO, CH4, CH3OH, C2+).
• Electronic metal-support interactions and microenvironment engineering are crucial for directing selectivity.
• N-doped carbons, oxides, and MXenes are representative supports, with performance evaluated by Faradaic efficiency, current density, and stability.

Conclusions:

• Rational design of SAC supports is key to achieving high selectivity and efficiency in CO2RR.
• Future directions include operando spectroscopy, data-driven analysis, machine learning, and integration into industrial electrolyzers.
• SACs hold significant potential for carbon-neutral chemical production.