Catalytic Mechanisms of Carbon Monoxide on Gold Nanostructures

Gold nanoparticles and nanoclusters have emerged as remarkably active catalysts for low-temperature carbon monoxide oxidation, overturning the long-held view that bulk gold is catalytically inert. Reactivity is governed by size-dependent electronic structure, by the metal–support interface and by dynamic surface restructuring under reaction conditions. At the atomic scale, adsorbed carbon monoxide binds to low-coordinated gold atoms at edges and corners, while molecular oxygen is activated either at the periphery of the nanoparticle or via neighbouring oxygen vacancies on reducible oxide supports. The interplay between CO adsorption strength and O2 dissociation barrier dictates turnover frequency, with optimum rates observed for clusters in the range of a few nanometres. Under operando conditions, nanoparticles undergo reversible shape and oxidation-state changes, generating transient active sites that enhance single-molecule reactivity. These insights underpin the rational design of gold-based catalysts for air purification, automotive exhaust treatment and portable power units, highlighting the global significance of elucidating fundamental reaction pathways on the nanoscale.

Research from Nature Portfolio

Recent studies have employed environmental transmission electron microscopy to visualise, in real time, the dynamic restructuring of gold nanoparticles during CO oxidation. These experiments reveal that active sites emerge at under-coordinated facets which form and dissolve in response to reactant pressures, correlating with transient increases in turnover frequency. Complementary work on single-atom gold catalysts supported on ceria demonstrates that isolated Au sites can drive CO oxidation at ambient temperatures via a Mars–van Krevelen mechanism, where lattice oxygen from the support replenishes surface O2 and regenerates active sites. Theoretical investigations have further defined the electronic factors that control CO adsorption energy and O2 activation on gold nanoclusters, showing how cluster charge and support interaction tune the reaction barrier and selectivity.

Catalytic Mechanisms of Carbon Monoxide on Gold Nanostructures publication trend

The graph below shows the total number of articles in catalytic mechanisms of carbon monoxide on gold nanostructures across all publications each year (not limited to Nature Index journals).

Technical terms

Under-coordinated atom: An atom at the surface of a nanoparticle with fewer neighbouring atoms than in the bulk, leading to higher chemical reactivity.

Mars–van Krevelen mechanism: A catalytic cycle in which lattice oxygen from a support participates in oxidation reactions and is replenished by gas-phase oxygen.

Turnover frequency (TOF): The number of reactant molecules converted per active site per unit time, a measure of catalyst activity.

Operando conditions: Experimental measurements made while a catalyst is functioning under realistic reaction environments, linking structure to function.

References

1. Gold oxide formation on Au(111) under CO oxidation conditions at room temperature. Physical Chemistry Chemical Physics (2024).