Electroreduction of CO2 powered by solar or wind electricity offers a sustainable approach toward valuable chemicals and fuels. Among the various products that can be generated from CO2 reduction, CO is of particular interest considering the market scale and economic viability. It can either be directly applied as feedstock for the chemical industry or further electrochemically reduced to hydrocarbon fuels. Despite its promise, the energy conversion and chemical transformation efficiencies of CO2 reduction are still largely limited by the lack of active and selective electrocatalysts. Alloying is an important strategy for the design of catalytic materials beyond pure metals. The conventional alloy catalysts however lack precise control over the local atomic structures of active sites. In this talk, I will introduce a new strategy to enhance the efficiency of CO2 reduction by engineering the ensemble size of active sites on bimetallic catalysts. A series of Pd@Au electrocatalysts are synthesized by decorating Au nanoparticles with Pd of controlled doses, giving rise to bimetallic surfaces containing Pd ensembles of various sizes. Their catalytic activity for reduction of CO2 to CO exhibits a volcano-like behavior in dependence of the Pd content, which is attributed to the variation of Pd ensemble sizes and the corresponding tuning of adsorption properties. Density functional theory calculations reveal that dispersion of strongly binding metal sites, such as Pd, on the surface of a weak binding metal, e.g., Au, could combine the advantages of the two metals, simultaneously lowering the energy barrier for CO2 activation and mitigating *CO poisoning. It was further proved that an intermediate ensemble size of active sites, such as Pd dimers, balances between the two rate-limiting factors and achieves the highest activity for CO2 reduction.

Ensemble effect in bimetallic electrocatalysts for CO2 reduction

Macromolecular Chemistry: The Second Century

[Author Benefits](https://scimeetings.acs.org/?utm_source=pubs_content_marketing&utm_medium=website&utm_campaign=0320_MCF_NPI_Launch_Spring_Homepage&ref=pubs_content_marketing)

[How to use SciMeetings](https://storage.googleapis.com/dl.morressier.com/acs/SciMeetings-ACSSpring2020-HowToGuide_M3020-Final.pdf)

[Frequently Asked Questions](https://storage.googleapis.com/dl.morressier.com/acs/SciMtng_ACSNMSp2020_FAQ_M3120_Final.pdf)

ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.