Low-Pt-content hierarchical selenide nanoarrays for accelerated hydrogen evolution through optimized hydrogen...

The development of electrocatalysts that combine low noble-metal loading with high catalytic activity is an important strategy for improving the efficiency of hydrogen evolution reaction (HER). Herein, a hierarchical PtSe₂/CoSe₂/MoSe₂/NiSe nanoneedle array catalyst, denoted as PtCoMoNi-Se, was fabricated to exploit the synergistic interactions among multiple transition-metal selenides for efficient hydrogen evolution. Using polyoxometalates as precursors, PtCoMoNi-Se was successfully synthesized using a facile two-step hydrothermal method, with a platinum (Pt) loading of only 1.71 wt%. Despite its low noble-metal content, PtCoMoNi-Se exhibited excellent HER activity, which was primarily attributed to its moderate Gibbs free energy of hydrogen adsorption (ΔG_H) and the strong interactions between H₂O molecules and multiple catalytic active sites. Density functional theory calculations in combination with in situ infrared spectroscopy demonstrated that the multiphase interfacial structure synergistically facilitates water activation, the adsorption and conversion of hydrogen intermediates, and the subsequent formation of H₂. Accordingly, PtCoMoNi-Se requires overpotentials of only 49 and 202 mV to achieve a current density of 10 mA cm^-2 in an alkaline electrolyte and simulated seawater, respectively. In comparison, commercial Pt/C requires corresponding overpotentials of 38 and 270 mV under the same conditions. These results demonstrate that the rational fabrication of low-Pt-content multimetallic selenides with strongly coupled multiphase interfaces provides an effective materials-design strategy for developing high-performance HER electrocatalysts.