Unconventional-Phase 1T′-Transition Metal Dichalcogenide Monolayers Grown on Amorphous Templates for Highly Efficient Hydrogen Evolution

Hydrogen is a promising clean energy carrier to address global energy and environmental challenges. Although platinum (Pt)-based catalysts are the benchmark for the hydrogen evolution reaction (HER), their high cost and scarcity limit their widespread application. Two-dimensional transition metal dichalcogenides (TMDs), particularly with the unconventional 1T′ phase, have emerged as promising alternatives, yet synthesizing them with high phase purity and stability remains challenging. Here, by using amorphous phosphorus (P)-doped Pd nanoparticles (a-PdP NPs) as templates, we develop a facile and general wet-chemical method to synthesize high-phase-purity and stable 1T′-TMD monolayers (MLs), including MoS2, WS2, and MoWS2, to construct a-PdP@1T′-TMD core–shell NPs. Experimental and theoretical analyses reveal that the formation and stabilization of 1T′-MoS2 MLs are attributed to the strong Pd–S interaction, electron donation from oleylamine, and amorphous nature of the template. The resulting a-PdP@1T′-MoS2 catalyst exhibits superior HER performance, requiring an overpotential of only −182.3 mV to achieve 1,000 mA·cm–2 and maintaining high stability for over 500 h at 500 mA·cm–2, outperforming the commercial Pt/C and placing it among the best reported MoS2-based catalysts. Impressively, the synthesized a-PdP@1T′-MoS2 can also be used as an efficient and stable support to grow single-atomically dispersed Pt with further enhanced HER activity, indicating its promise as a versatile platform for the design and preparation of advanced electrocatalysts.