Bridging-induced densified MXene films with ultralow single-atom Pt loading for highly efficient hydrogen evolution

Platinum (Pt)‐based materials have garnered significant attention due to their exceptional electrocatalytic performance and potential for advancing water splitting technology. However, reducing Pt usage simultaneously maintaining its high catalytic performance remains a critical challenge. Here, ultralow content (0.25 wt‰) of Pt single atoms (SAs) were successfully anchored onto Ti_3-xC₂T_y MXene nanosheets, followed by the preparation of self-supported, densified MXene film electrocatalysts through a sequential bridging process involving hydrogen and covalent bonding (denoted as 0.25-HCM@Pt_SA). The resulting 0.25–HCM@Pt_SA film catalyst exhibits excellent hydrogen evolution reaction (HER) performance, showcasing a small overpotential of 48 mV at 10 mA cm⁻², an ultrahigh mass activity of 28.93 A mg_Pt⁻¹, and a large turnover frequency of 23.45 s⁻¹ at an overpotential of 100 mV. Furthermore, density functional theory calculations reveal that the anchoring Pt SAs on the densified MXene film reduces the binding energy and hybridization strength between H atoms and the support, contributing to rapid hydrogen adsorption−desorption kinetics and high HER activity. This work provides a promising and scalable strategy for designing 2D materials-based noble metal electrocatalysts with ultralow metal loading and high catalytic activity.