Dr. Hao Shen

Single-Molecule Imaging and Asymmetric Materials in Catalysis

Catalysis forms the bedrock of contemporary society, enhancing reaction rates by presenting alternative pathways with reduced activation energies. As such, catalysts play a pivotal role in driving chemical transformations. The intricate diversity in catalyst structures often poses challenges in establishing the structure-activity relationship during the catalyst design. Consequently, the Shen Research Group concentrates on leveraging single-molecule methodologies to delve into the performance of individual catalysts on a per-reaction basis. This investigation encompasses diverse forms of catalysis encompassing chemical, photochemical, and electrochemical processes.

(1) Unveiling reaction mechanisms

The single-molecule approach employed by the Shen Research Group boasts remarkable spatiotemporal resolution, enabling the elucidation of reaction mechanisms. By scrutinizing individual product formations, we extract single reaction turnover times, bypassing the ensemble averaging bias inherent in conventional techniques. Employing cutting-edge super-resolution imaging algorithms, we transcend the limitations of optical microscopes' diffraction, unveiling reactions transpiring at the scale of tens of nanometers. This potent chemical imaging technique empowers us to scrutinize the structure-activity interplay at the sub-nanoparticle level.

(2) Pioneering novel catalysts through the integration of asymmetric materials

Chiral molecules, inherently non-superimposable with their mirror images, abound in biological systems, fulfilling pivotal functions. Notably, amino acids and proteins exhibit L chirality, while sugars, including deoxyribose, possess D chirality. Drawing inspiration from the architecture of biocatalysts, the Shen Research Group collaborates with the Mao Research Group at KSU to synthesize an innovative catalyst variant named "coronazyme." These coronazymes feature a nanoparticle core encircled by a chiral DNA corona. This synergistic interplay between the core and corona bestows them with superior reactivity and selectivity, outperforming conventional nanoparticle catalysts. Our efforts encompass the development of diverse coronazyme iterations and exploring their catalytic role in a range of chemical reactions.

(3) Catalysis under external stimuli

The performance of catalysts remains intricately linked to their operational conditions. Conversely, manipulating these conditions through external stimuli can significantly enhance catalytic efficacy. Our research team has pioneered an advanced imaging system, enabling real-time observation of catalytic performance while concurrently modifying catalyst structures. Through our instrumental innovations, we scrutinize reactions influenced by light, force, and magnetic field stimuli. Moreover, we unravel the fundamental mechanisms underpinning these catalytic enhancements.