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For increasing scalability and reducing cost, transition metal dichalcogenides-based electrocatalysts presently have been proposed as substitutes for noble metals to generate hydrogen, but these alternatives usually suffer from inferior performance. Here, a Ravenala leaf-like W xC@WS2 heterostructure is grown via carbonizing WS2 nanotubes, whose outer walls being partially unzipped along with the W x C 'leaf-valves' attached to the inner tubes during the carbonization process. This heterostructure exhibits a catalytic activity for hydrogen evolution reaction with low overpotential of 146 mV at 10 mA cm−2 and Tafel slope of 61 mV per decade, outperforming the performance of WS2 nanotubes and W xC counterparts under the same condition. Density functional theory calculations are performed to unravel the underlying mechanism, revealing that the charge distribution between W xC and WS2 plays a key role for promoting H atom adsorption and desorption kinetics simultaneously. This work not only provides a potential low-cost alternative for hydrogen generation but should be taken as a guide to optimize the catalyst structure and composition. [ABSTRACT FROM AUTHOR]

As an effective alternative to noble platinum electrocatalyst, earth abundant and inexpensive layered transition metal dichalcogenides (TMDs) are investigated for the hydrogen evolution reaction (HER). Compared with binary TMDs, the tunably composed ternary TMDs have hitherto received relatively little attention. Here, few-layered ternary WS2(1− x)Se2 x nanoribbons (NRs) with metallic 1T phases, much more catalytically active in HER, are prepared for the first time. The favorable Δ GHo introduced by the tensile region on the surface, along with the presence of local lattice distortions of the WS2(1− x)Se2 x nanoribbons with metallic 1T phases, greatly promotes the HER process. These ternary NRs achieve the lowest overpotential of ≈0.17 V at 10 mA cm−2 and a Tafel slope of ≈68 mV dec−1 at a low catalyst loading (≈0.30 ± 0.02 mg cm−2). Notably, the long-term durability suggests the potential of practical applications in acid electrolytes. The results here suggest that the ternary WS2(1− x)Se2 x NRs with 1T phases are prominent alternatives to platinum-based HER electrocatalysts. [ABSTRACT FROM AUTHOR]