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.