Ultrathin PtSe2 Nanowires in Single‐Walled Carbon Nanotubes for Hydrogen Evolution Reaction

Platinum selenide (PtSe2) has shown great potential for application in electrocatalysis. One‐dimensional (1D) nanostructures are particularly advantageous for enhancing catalytic performance, as they expose abundant active sites at the edges and enable rapid charge transport. However, the synthesis of 1D PtSe2 nanostructures for efficient electrocatalysis remains a challenge. Here, we report the controllable synthesis of ultrathin (0.4‐2.0 nm) PtSe2 nanowires (NWs) using single‐walled carbon nanotubes (SWCNTs) as a confined template via direct selenization by chemical vapor deposition (CVD). The atom‐resolved electron microscope combined with spectroscopy and theoretical calculations revealed that PtSe2 NWs grow anisotropically along the <110> direction inside the SWCNTs, possessing zigzag edges and higher thermodynamical stability. Owing to the rich‐edges with abundant unsaturated Pt atoms, the as‐prepared PtSe2 NWs exhibit excellent hydrogen evolution reaction (HER) activity at an extremely low Pt loading of 4.684 wt%, with an overpotential of 47 mV@10 mA cm‐2 and a Tafel slope of 41.7 mV dec‐1. This work provides a novel strategy for synthesizing 1D ultrathin NWs and offers the potential to achieve low‐cost and efficient Pt‐based catalysts in the future.