Vertical 1T-TaS₂ Synthesis on Nanoporous Gold for High-Performance Electrocatalytic Applications

2D metallic TaS₂ is acting as an ideal platform for exploring fundamental physical issues (superconductivity, charge-density wave, etc.) and for engineering novel applications in energy-related fields. The batch synthesis of high-quality TaS₂ nanosheets with a specific phase is crucial for such issues. Herein, the successful synthesis of novel vertically oriented 1T-TaS₂ nanosheets on nanoporous gold substrates is reported, via a facile chemical vapor deposition route. By virtue of the abundant edge sites and excellent electrical transport property, such vertical 1T-TaS₂ is employed as high-efficiency electrocatalysts in the hydrogen evolution reaction, featured with rather low Tafel slopes ≈67-82 mV dec^-1 and an ultrahigh exchange current density ≈67.61 µA cm^-2 . The influence of phase states of 1T- and 2H-TaS₂ on the catalytic activity is also discussed with the combination of density functional theory calculations. This work hereby provides fundamental insights into the controllable syntheses and electrocatalytic applications of vertical 1T-TaS₂ nanosheets achieved through the substrate engineering.