CO₂‑Induced Phase Engineering: Protocol for Enhanced Photoelectrocatalytic Performance of 2D MoS₂ Nanosheets

Molybdenum disulfide (MoS₂) is a promising non-precious-metal catalyst, but its performance is limited by the density of active sites and poor electrical transport. Its metallic 1T phase possesses higher photoelectrocatalytic activity. Thus, how to efficiently increase the concentration of the 1T phase in the exfoliated two-dimensiaonal (2D) MoS₂ nanosheets is an important premise. In this work, we propose a strategy to prepare a 2D heterostructure of MoS₂ nanosheets using supercritical CO₂-induced phase engineering to form metallic 1T-MoS₂. Theoretical calculations and experimental results demonstrate that the introduced CO₂ in the 2H-MoS₂ host can prompt the transformation of partial 2H-MoS₂ lattices into 1T-MoS₂. Moreover, the electrical coupling and synergistic effect between 2H and 1T phases can greatly facilitate the efficient electron transfer from the active sites of MoS₂, which significantly improves the photocatalytic performance