(509d) Engineering Bimetallic Interface and Revealing the Mechanism for CO2 Electroreduction Reaction to C3+ Liquid Chemicals

Intermittent renewable electricity powered reduction reaction of CO₂ (CO₂RR) to value-added liquid C₃₊ chemicals is a net-zero-carbon process and could reduce logistics required to transport fuels and increase local resiliency to power outages and fuel consumption. However, current catalyst designs for CO₂RR-to-C₃₊ are via the conventional trial and error method due to the unknown reaction mechanism. To address this challenge, we explored the CO₂RR-to-C₃₊ mechanism via density functional theory (DFT) calculations and designed a Pd/Au bimetallic catalyst.¹ We investigated C-C coupling reactions from C₁ to C₅, identifying ^*CH₂ as the key intermediate and CH₂-C₁ coupling as the potential rate-determining step for C₃₊ formation. Remarkably, the PdAu(111) interfacial site exhibited the lower energetic requirements for the key intermediate ^*CH₂ formation and the potential RDS. Our results also show that increasing CO surface coverages promoted the formation of bimetallic interfacial sites, leading to lower energetics in the CH₂-C₁ coupling step. As a result, this enhancement favored C₃₊ formation in CO₂RR. Via varying the Pd/Au ratios and engineering the d-band center of the interfacial site, we constructed a volcano-like plot of CH₂-C₁ kinetics as a function of the binding strength of key intermediate ^*CH₂ and optimized the bimetallic surface for promoting C₃₊ production.

Our findings could guide the rational design of engineering bimetallic interfaces and their near-surface microenvironment for CO₂RR to valuable C₃₊ liquid chemicals. Future work aims to create a robust and dynamic learning algorithm to establish a comprehensive model to automatically generate and select the most effective alloy interface sites for CO₂RR, targeting the production of longer carbon-chain fuels.

References

(1) Xu, Y.; Ross, M. B.; Xin, H.; Che, F. Engineering bimetallic interfaces and revealing the mechanism for carbon dioxide electroreduction to C3+ liquid chemicals. Cell Reports Physical Science 2023, 4 (12).