Phase-Engineered Dichalcogenides/Fluorine-Free V₄C₃T_x (T = OH, O) Heterostructures for pH-Universal Hydrogen...

This research addresses the pH-dependency limitation in electrocatalytic hydrogen evolution reactions (HER) by creating heterostructures through the chemical bonding between 2D-dichalcogenides and V₄C₃T_x (T = OH, O) planes. The one-step solvothermal synthesis employed in this study constructs a synergistically interacted 1T phase of, e.g., MoS₂ and V₄C₃T_x MXene, demonstrating an omnidirectional improvement on catalytic stability, active site exposure, surface area enlargement, electrical conductivity, and hence enhancement of water dissociation activities. Despite the notable progress in creating hydrogen production catalysts with ground breaking performances, a significant gap remains in the availability of catalysts capable of functioning effectively under high current densities. The catalyst 1T MoS₂@V₄C₃T_x shows remarkable activities under the current density of 1000 mA cm^-2, which require overpotentials of 16, 24, and 37 mV in 0.5 m H₂SO₄, 1 m KOH, and 0.1 m PBS electrolytes, respectively at 10 mA cm^-2, and exhibits excellent HER performance with small overpotentials of 103.16 and 138 mV to achieve current densities of 500 and 1000 mA cm^-2, respectively, with outstanding stability for 1000 cylic voltammetric cycle HER test without degradation in acidic media. Enhanced HER performance has also been observed in other 2D-dichalcogenides/V₄C₃T_x heterostructures, providing prospects for phase-engineered dichalcogenides/fluorine-free V₄C₃T_x composites for pH-universal HER.