Nickel-palladium (Ni-Pd) bimetallic nanoparticles were fabricated using hydrazine hydrate by chemical reduction. The synthesized nanoparticles were characterized by employing various spectroscopic techniques to determine the structural, morphological, elemental, and optical properties. The crystalline nature, purity of phase, and crystallite size of the synthesized Ni-Pd nanoparticles were confirmed by XRD. The average crystallite size was found to be 5.45 nm. SEM revealed highly agglomerated, spherical, cluster-like nanoparticles with an average particle size of 50.277±19.727nm; EDS analysis showed the composition of Ni (64.32 wt.%), Pd (14.58 wt.%), and other detected elements; the oxygen signal was attributed to surface oxidation. Fourier transform infrared spectroscopy (FTIR) revealed metal-oxygen bonds and the presence of surface functional groups, and UV-Visible spectroscopy showed a characteristic absorption peak at 291 nm, confirming nanoparticle formation. The gas sensing performance of the synthesized Ni-Pd nanoparticles was examined towards the H₂S, ethanol, LPG, CO₂, and NO₂ gases under optimized operating conditions. Ni-Pd nanoparticles offer high gas sensing performance with rapid and reversible response–recovery characteristics, strong selectivity toward CO₂, and optimal operation at 80 °C with 93.56% response and 72 s recovery time, making them promising candidates for reliable, real-time gas detection and safety monitoring applications.

Keywords: Bimetallic Ni-Pd Nanoparticles; Gas Sensor; Chemical Synthesis; Hydrazine Hydrate;