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              Department of Materials Science, University of Suwon

Electrocatalytic performance is fundamentally governed by the nature and distribution of active sites, which dictate the adsorption energy of reaction intermediates and the overall reaction kinetics. Conventional electrocatalysts often suffer from the inhomogeneous distribution of active sites, leading to localized activity disparities and inefficient electrocatalytic performance. Various strategies, such as heteroatom doping and cation substitution, have been explored to enhance catalytic activity by modulating electronic structures and charge transfer properties. However, the dopants or heterostructures can only generate a limited number of active sites locally on the surface, leading to disproportionate reaction activities from the active center to the bulk, and consequently, a high density of dopants is needed.

In this seminar, we introduce a breakthrough electrocatalyst design by leveraging semiconducting materials, traditionally considered suboptimal for catalysis due to their poor electric conductivity and limited charge transport channels. Here, we demonstrate that iodine-doped single-walled carbon nanotubes (I-SWNTs), exhibiting p-type degenerate semiconductor properties (i.e., behave like metals due to high dopant concentrations), as a new class of carbon-based electrocatalysts. We found that the linear polyiodide chains inside the carbon nanotubes can degenerate the electronic structure, resulting in metal-like conductivity while maintaining a tunable electronic structure for highly selective and efficient electrocatalysis. Furthermore, we extend this concept to semiconducting ceramic materials, revealing their potential for advanced electrochemical applications through band structure engineering and defect-state optimization. Our findings challenge the conventional limitations of semiconductors in catalysis and provide a new paradigm for designing high-performance electrocatalysts with precisely controlled active site architectures.