Atomically Dispersed Sn on Core‐Shell MoS₂ Nanoreactors as Mott‐Schottky Phase Junctions for Efficient Electrocatalytic Hydrogen Evolution

The electrocatalytic hydrogen evolution reaction (HER) plays a pivotal role in electrochemical energy conversion and storage. However, traditional HER catalysts still face significant challenges, including limited activity, poor acid resistance, and high costs. To address these issues, a hollow core‐shell structured 2H@1T‐MoS 2 ‐Sn 1 nanoreactor is designed for acidic HER, where Sn single atoms are anchored on the shell of 2H@1T‐MoS 2 Mott‐Schottky phase junction. The 2H@1T‐MoS 2 ‐Sn 1 catalyst demonstrates exceptional HER performance, achieving an ultralow overpotential of 9 mV at 10 mA cm −2 and a Tafel slope of 16.3 mV dec −1 in acidic media—the best performance reported to date among MoS 2 ‐based electrocatalysts. The enhanced performance is attributed to the internal electric field at the Mott‐Schottky phase junction, which facilitates efficient electron transfer. Additionally, the Sn single atoms modulate the electronic structure of Mo atoms within the Sn‐S 2 ‐Mo motif, inducing a significant shift in the d‐band center and thereby optimizing the dehydrogenation process. This work presents a novel electrocatalyst design strategy that simultaneously engineers interfacial charge transfer and surface catalysis, offering a promising approach for advancing energy conversion technologies.