Atomically Dispersed Sn on Core-Shell MoS 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-Sn nanoreactor is designed for acidic HER, where Sn single atoms are anchored on the shell of 2H@1T-MoS Mott-Schottky phase junction. The 2H@1T-MoS-Sn catalyst demonstrates exceptional HER performance, achieving an ultralow overpotential of 9 mV at 10 mA cm and a Tafel slope of 16.3 mV dec in acidic media-the best performance reported to date among MoS-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-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.