Research

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• We develop detailed, quantitative understanding of the structure-property relationship underpinning the optical tunability of complex nanostructures at both the ensemble and single-particle levels through combined experimental and computational efforts.

• We use surface-enhanced Raman scattering (SERS) as an surface-sensitive spectroscopic tool with unique time-resolving and molecular finger-printing capabilities to fine-resolve the dynamic interfacial binding and transforming behaviors of molecular ligands on locally curved metallic nanoparticle surfaces. The results of deliberately designed spectroscopic measurements, further corroborated by density functional theory calculations, provide critical insights on the rich surface chemistry of colloidal metallic nanoparticles.

• We study plasmon-driven photocatalysis through time-resolved SERS measurements. Resolving the reaction kinetics on one particle at a time using SERS provides a unique means to quantitatively correlate the reaction kinetics with the plasmonic characteristics of the photocatalysts at the single-particle level, enabling us to pinpoint the effects of several key factors dictating the reaction kinetics and yields, such as hot charge carriers, local-field enhancements, molecular adsorbate conformations, and plasmonic photothermal heating.

• We develop robust synthetic approach to sub-5 nm nanocatalysts of the platinum group elements (Pt, Pd, Rh, Ru, Os, Ir, and their alloys) with precisely controlled particle sizes, narrow size distributions, ligand-free clean surfaces, and uniform spatial distribution over the support surfaces. The success in precisely tuning the particle size of ligand-free nanocatalysts within the sub-5 nm size window provides unique opportunities for us to gain detailed, quantitative insights concerning the intrinsic particle size effects on the pathway selection of catalytic molecular transformations.

• We develop new synthetic approaches to multimetallic nanostructures with tunable catalytic and electrocatalytic properties. The synthetic strategies are designed based on kinetic manipulation of several nanoscale structural remodeling processes, such as galvanic exchange, percolation dealloying, and seeded deposition. By deliberately tailoring the surface and interior architectures of these multimetallic nanostructures, we aim at optimizing their enzyme-mimicking and electrocatalytic properties for specifically targeted biomedical, sensing, and fuel cell applications.

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We acknowledge the following sponsors for supporting our current and past research:

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