NIR‐Responsive Plasmonic PtSb Alloys with Strong p‐d Orbital Hybridization for Synergistic Photothermal‐Catalytic Therapy

Developing platinum (Pt)-based nanostructures with strong near-infrared (NIR) plasmonic response and catalytic activity remains challenging for efficient photothermal-catalytic therapy, due to their poor optical tunability in the NIR region. Here, orbital-engineered PtSb nanoalloys are reported that exhibit broadband NIR plasmonic resonance and enhanced peroxidase (POD)-like activity, driven by strong p-d orbital hybridization between Pt and Sb. Finite-difference time-domain simulations further confirm the presence of localized surface plasmon resonance and enhanced electromagnetic field distribution in PtSb nanocrystals (NCs). The optimized Pt₈₄Sb₁₆ NCs demonstrate high NIR photothermal conversion efficiency and augmented POD-like catalytic activity, enabling synergistic reactive oxygen species (ROS) amplification and thermal ablation. In vitro and in vivo studies confirm that NIR-activated PtSb NCs induce robust apoptosis and immunogenic cell death, achieving potent therapeutic efficacy in breast cancer models. This work offers a promising strategy for engineering unconventional Pt-based plasmonic nanoalloys and expands their potential in photothermal-catalytic cancer therapy.