Universal cryo-thermal sculpting of transition metal dichalcogenides: simultaneous phase and size engineering for energy electrocatalysis.

The global quest for a sustainable energy matrix is fundamentally a crisis of material constraints where success relies on structural control at the atomic scale. Herein, we report a universal, physical protocol: cyclic rapid annealing and cooling (CRAC) that simultaneously orchestrates phase-engineering and dimensional reduction. By subjecting bulk TMDs (MoS2, MoSe2, and CoSe2) to extreme, repetitive cryo-thermal shocks, we induce a controlled structural fracturing that yields zero-dimensional (0D) nanoparticles with locked metastable phases (1T/cubic) through rapid kinetic quenching. Comprehensive characterization reveals a profound alteration of the materials' physical landscape: X-ray diffraction and spectroscopic analyses confirm a dominant metallic phase concentration, while electron microscopy unveils sub-10 nm nanoclusters with an abundance of exposed edge sites. Consequently, these CRAC-engineered 0D TMDs exhibit exceptional electrocatalytic performance, delivering very low overpotentials and robust kinetics for the hydrogen and oxygen evolution reactions (HER/OER), high-efficiency oxygen reduction reaction (ORR) pathways, and superior rate capability in super capacitive energy storage. This electrocatalytic prowess originates from the dual-modulation technique. By bridging the gap between materials engineering and electrochemistry, this work provides a universal and scalable blueprint for sculpting earth-abundant materials into high-performance catalysts, establishing a new frontier in the design of noble-metal-free energy technologies.