Amorphous materials are one kind of nonequilibrium materials and have become one of the most active research fields. Compared with crystalline solids, the theory of amorphous materials is still in infancy because their characteristic of atomic arrangement is more like liquid and has no long-range periodicity. Recently, as the representative of amorphous materials, amorphous molybdenum sulfide (a-MoS_x) with unique physical and chemical properties has been studied extensively. However, considerable debate surrounds the structure–property relationships of a-MoS_x owing to its diverse Mo-S motifs. Herein, we summarize recent discoveries and research results regarding a-MoS_x, whose structural characteristics, synthetic strategies, formation criteria, and comprehensive applications are discussed in detail. Finally, this review is ended with our personal insights and critical outlooks over the development of a-MoS_x.

Defect engineering is one of the effective strategies to optimize the physical and chemical properties of molybdenum disulfide (MoS₂) to improve catalytic hydrogen evolution reaction (HER) performance. Dislocations, as a typical defect structure, are worthy of further investigation due to the versatility and sophistication of structures and the influence of local strain effects on the catalytic performance. Herein, this study adopted a low-temperature hydrothermal synthesis strategy to introduce numerous dislocation-strained structures into the in-plane and out-of-plane of MoS₂ nanosheets. Superior HER catalytic activity of 5.85 mmol·g⁻¹·h⁻¹ under visible light was achieved based on the high-density dislocations and the corresponding strain field. This work paves a new pathway for improving the catalytic activity of MoS₂ via a dislocation-strained synergistic modulation strategy.