Dendritic WS ₂ Nanoribbon Networks Grown in Interfacial Confinement Space: Edge‐Rich Architectures for Enhanced Hydrogen Evolution

Fractally grown dendritic nanostructures exhibit exceptional potential across various applications, particularly in electrochemical catalysis, owing to their high surface area and abundant reactive sites. Such structures can be synthesized via diffusion‐limited aggregation (DLA), which requires tightly controlled growth conditions, such as a low precursor supply rate. Two‐dimensional materials, especially transition‐metal dichalcogenides (TMDCs), provide an ideal platform for realizing atomically precise dendritic architectures. In this study, we present a strategy for synthesizing fractal dendritic networks of monolayer WS ₂ nanoribbons by employing an interfacial nanoreactor to create a highly confined growth environment. The dendritic WS ₂ nanoribbons were formed at the interface between the monolayer WS ₂ and the growth substrate, facilitating a DLA‐dominated growth regime. Atomic‐scale structural analysis revealed atomically sharp edges of dendritic WS ₂ nanoribbon networks. High‐resolution scanning electrochemical cell microscopy demonstrated enhanced hydrogen evolution reaction activity, with the catalytic current localized at the dense edges. Furthermore, a combination of experimental analysis and theoretical modeling provided insights into the surface‐diffusion‐governed growth mechanism. These findings offer a new approach for designing edge‐rich TMDC nanostructures and pave the way for their integration into high‐performance catalytic and electrochemical devices.