Hydrogen gas sensing properties of Pd-decorated ZnO tetrapod nanostructures

Hydrogen is a promising and renewable energy carrier; however, its high permeability, flammability, and colorless, odorless, and tasteless characteristics necessitate the development of reliable detection methods. This study investigates the synthesis, characterization, and hydrogen sensing performance of palladium-decorated zinc oxide (ZnO) tetrapod nanostructures. ZnO tetrapods were synthesized via thermal oxidation of ball-milled zinc powders, with milling durations of 0, 3, and 10 h to optimize nanostructure uniformity. Structural and compositional analyses using Field Emission Scanning Electron Microscopy (FE-SEM), X-ray Diffraction (XRD), and X-ray Photoelectron Spectroscopy (XPS) confirmed successful decoration with Pd nanoparticles while preserving the wurtzite crystal structure of ZnO. Gas sensing measurements demonstrated that Pd decoration markedly enhanced hydrogen sensitivity; the optimal sample (Pd(0.5 %)/ZnO) exhibited a sensor response of approximately 200 % at 350 degrees C, significantly surpassing the similar to 25 % response of the undecorated ZnO. This synergistic effect also yielded rapid response (similar to 2 s) and recovery (similar to 7 s) times. These findings establish Pd-decorated ZnO tetrapod nanostructures as robust and efficient candidates for hydrogen sensing applications, offering high sensitivity, swift response, and excellent selectivity.