The fundamental catalytic mechanisms of chemical reactions where the reaction center is located within confined space at nanometer scale are very different from those in bulk solution, especially when the nanoconfined space is dimensionally close to the size of substrate molecules. Previous results from both theoretical studies of simplified model systems and ensemble experimental measurements have shown the nanoconfinement effects on catalytic activities. To understand the <i>in situ</i> dynamic behaviour of catalytic chemical reactions under nanoconfinement, we synthesise a nanocatalyst platform with reaction centers are protected with well-aligned and well-controllable mesoporous shell. Previous experimental results indicated a confinement-induced enhancement of catalytic activities of Pt nanoparticles and a weaken adsorption strength of substrate molecules on Pt nanoparticles quantitatively at single molecule and single particle level with turn-over resolution. Here, we synthesise catalysts of nanometer-size porous structures with different geometries (nanopore length and nanopore diameter) and distinct chemical environments (hydrophilic vs hydrophobic) to study the dynamic processes of catalytic reactions under different nanoconfinement effects. From single molecule imaging and single particle experimental results, we uncovered the distinct catalytic reaction kinetics under nanoconfinement with different nanopore geometries. The chemical environments inside nanopore also result largely different nanoconfinement effects. Specially, the oxidation reaction of amplex red on Pt nanoparticles is much more accelerated in a hydrophobic environment compared to that in hydrophilic environment. The specially designed nanocatalysts are proven to be a versatile platform for studies on different aspects of the catalytic nanoconfinement effects, such as surface chemical properties and nanopore morphology.

Quantitative single-molecule and single particle study of catalytic reaction kinetics in versatile nanoconfinement under <i>Operando</i> condition

256th National Meeting (2018)

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Quantitative single-molecule and single particle study of catalytic reaction kinetics in versatile nanoconfinement under Operando condition