Unveiling of Unpaired Surface Spins Regulated Magnetism in 2D α‐Te Nanosheets: an Implication on Magnetoelectric Driven Hydrogen Evolution

Abstract

Abstract Quasi‐2D tellurium (Te) unlocks surface spins (of valence 5p4 electrons) of tunable ferromagnetic order and response to strain‐engineered electronic properties of widespread applications. In spin–orbit coupling, the inversion symmetry is broken in a 1 S 0 → 3 S 1 spin‐transition of the ground electronic state, a synergetic pathway to charge spin‐order under applied driving forces. The surface magnetism, combined with the ferroelectricity, gives a giant magnetoelectric response (absent in 1 S 0 bulk Te state) that is explored to boost the H 2 evolution reaction (HER) with 2D α‐Te as a synergetic catalyst. High‐quality 2D α‐Te synthesized as nanosheets is ordered primarily along (001) facets at duly enhanced d 001 atomic spacing in the 5s 2 ‐Te lone pair electrons (diamagnetic) are spaced (Coulomb repulsion) via the 5p 2 unpaired spins. Poled 2D α‐Te in small fields, such as 30 mT, presents a HER overpotential that is decreased up to 100 mV, while the Tafel slope is declined up to 138 from 211 mV dec −1 for the bulk sample. The electrochemical stability of 2D α‐Te is found quite impressive with 93% current retention (71% if non‐magnetized) under chronoamperometric conditions. The results present that the 2D α‐Te plays a game‐changing role towards sustainable energy technologies, spintronics, and next‐generation magnetoelectric devices.