Plasmon-Enhanced Hydrogen Evolution over an <i>In Situ</i> Constructed Pt Nanoparticles–Ti ₃ C ₂ MXene Hybrid Electrocatalyst

The electrocatalytic hydrogen evolution reaction (HER) is widely recognized as a promising pathway for sustainable energy conversion and storage. Recently, plasmonic enhancement has attracted increasing attention as an effective strategy to improve HER performance by harvesting incident light. However, most metal nanoparticles (NPs) with excellent HER catalytic activity, such as Pt, exhibit a negligible localized surface plasmon resonance (LSPR) effect, thereby limiting their overall efficiency. In this study, we constructed a Pt NPs-Ti₃C₂ MXene hybrid electrocatalyst via an <i>in situ</i> reduction approach, in which Ti₃C₂ MXene simultaneously acted as the reductant, structural support, and plasmonic mediator. Under 808 nm laser irradiation, Ti₃C₂ MXene generated a strong LSPR effect, and the resulting hot electrons were efficiently injected into the Pt NPs/Ti₃C₂ MXene interface, where they actively contributed to the HER process. Consequently, the hybrid catalyst achieved an overpotential as low as 51 mV at 10 mA cm^-2 and a favorable Tafel slope of 61.29 mV dec^-1 while maintaining excellent stability. Finite element simulations further confirmed that the LSPR-induced local field enhancement concentrated hot electrons at the Pt NPs/Ti₃C₂ MXene interface, thereby lowering the activation barrier and accelerating the charge transfer. Overall, this work demonstrates a simple yet effective plasmon-catalyst coupling strategy that provides valuable insights for the design of next-generation plasmon-enhanced electrocatalysts for efficient hydrogen production.