Stabilized single-atom catalysts on 2D supports for CO₂-to-liquid fuel conversion: beyond conventional DFT insights via stability-selectivity descriptor mapping.

BACKGROUND

The electrochemical reduction of carbon dioxide (CO₂) into liquid fuels is a promising route toward sustainable energy storage. Single‑atom catalysts (SACs) off er high atom efficiency and tunable electronic structures but suffer from instability and aggregation under reaction conditions. Stabilizing SACs on conductive two‑dimensional (2D) supports may overcome these limitations and enhance selectivity toward C₂+ liquid products.

METHODS

Density functional theory (DFT) calculations were performed to evaluate the stability, charge transfer characteristics, and CO₂RR reaction energetics of transition‑metal SACs anchored on nitrogen‑doped graphene and MXene substrates. Adsorption energies, Bader charge transfer, and limiting potentials were integrated into a unified stability-selectivity descriptor map to enable rapid screening of SAC-support combinations.

RESULTS

Strong coordination between metal centers and heteroatom‑doped 2D lattices suppresses migration and aggregation, significantly improving thermodynamic stability. Electronic coupling with the conductive supports enhances charge redistribution at the active site, promoting selectivity toward C₂+ liquid fuels such as ethanol and propanol. The proposed descriptor framework reveals clear correlations between binding strength, charge transfer, and catalytic performance, enabling prediction of high‑performing SAC-support pairs beyond case‑specific simulations.

CONCLUSIONS

Stabilized SACs on 2D supports represent a robust platform for CO₂‑to‑liquid‑fuel conversion. The introduced stability-selectivity descriptor provides a predictive tool for catalyst discovery, while the conceptual design of dual‑functional MXene-graphene hybrid supports offers a new direction for engineering durable and selective SAC systems.