This research investigates the enhancement of photocatalytic efficiency for nitric oxide (NO) oxidation under solar irradiation by exploiting the surface plasmon resonance (SPR) effect of palladium nanoparticles (Pd NPs). The SPR effect of Pd NPs extended the light absorption range from 357 nm to 432 nm, facilitated charge separation, and reduced electron-hole recombination, directly enhancing photocatalytic efficiency. Pd NPs were successfully deposited onto ZnSn(OH)₆ (ZHS) cubic structures, narrowing the band gap from 3.54 eV to 2.83 eV and significantly boosting photocatalytic activity. The Pd-ZHS composite achieved an NO oxidation efficiency of 59 % under visible light and 77.9 % under solar light, with minimal NO₂ production and excellent stability even after five cycles. Notably, the kinetic reaction rate constants nearly doubled, reaching 0.11958 min^-1 under visible light and 0.30601 min^-1 under solar light. Although solar light slightly increased NO₂ by-product formation due to higher Pd concentrations, the uniform distribution of Pd NPs improved charge separation and transport, leading to a threefold increase in the kinetic reaction rate and a 1.5-fold improvement in photocatalytic efficiency compared to pristine ZHS. The cubic structure and stability of ZHS provided an ideal platform for uniform Pd NP deposition, enhancing the material’s catalytic properties. These findings highlight the pivotal role of Pd NPs and the SPR effect in advancing photocatalyst design for effective NO oxidation and offer a promising approach to mitigating nitrogen oxide emissions in environmental applications.