In this work, palladium nanoparticles (Pd NPs) are synthesized by laser ablation in liquid (PLAL) with wavelength 532 nm (second harmonic Nd:YAG laser) at different laser energies 360, 660, and 800 mJ with 200 pulses and an electric coil is used to generate a magnetic field. The resulting nanosolution was deposited on the previously prepared PS. The morphological and structural properties of the prepared substrates (Pd NPs/PS) are calculated by X-ray diffraction (XRD) pattern, Atomic Force Microscope (AFM), and Transmission Electron Microscopy (TEM). Their results showed that with the increase in the energy of laser pulse, the average particle size was 30.73, 22.60, and 18.01 nm. Optical properties of Photoluminescence (PL) spectra show decrease of energy band gap at 2.38, 2.43, and 2.47 eV with an increase in the energy. The sensitivity of application samples Pd NPs/PS/Si gas sensors for NO2 and H2S gas was also investigated with respect to temperature variations. Pd NPs/PS/Si gas sensors have a maximum sensitivity of NO2 gas around 52.6% at 2 5 ∘ C for sample prepared at energy 360 mJ but the highest sensitivity of H2S gas was 31.2% at 2 5 ∘ C for energy of 660 mJ. The effects of the operating temperature on reaction and recovery durations for various laser ablation energies are also discussed. [ABSTRACT FROM AUTHOR]