Highly durable metal ensemble catalysts with full dispersion for automotive applications beyond single-atom catalysts

Abstract

Reducing the size of metal nanoparticles down to the single-atom level has been actively pursued to maximize the use of precious metals. Recently, single-atom catalysts, in which all the metal atoms are isolated on a support with 100% dispersion, have received much attention. However, the lack of ensemble sites prevents valuable surface reactions that require metal proximity to occur. Here, we present metal (Pt, Pd and Rh) ensemble catalysts with 100% dispersion and a reduced metallic surface state. More specifically, nanoceria particles were anchored on Al3+penta sites of activated γ-alumina, and then metal was deposited and reduced. The ensemble catalysts are highly durable: their structure was maintained even after hydrothermal ageing at 900 °C for 24 h or after long-term reaction. These catalysts have superior activity and durability for three-way catalytic reactions and can provide insights beyond single-atom catalysts for heterogeneous catalysis. Supported single atoms can minimize metal utilization in catalysis, although reactivity restrictions exist. Here, fully exposed Pt, Pd and Rh ensembles localized on CeO2 islands anchored onto partially reduced γ-Al2O3 are introduced as a superior and durable alternative for three-way catalysis.