Sol-Gel Synthesis of Pd@PdO Core-Shell Nanoparticles and Effect of Precursor Chemistry on Their Structural and Optical Properties

摘要

Nanocrystalline Pd@PdO core-shell (a) were synthesized by aqueous sol-gel transformations from precursor [Cl2PdL] (1) {where, L=8-(2-pyridylmethoxy)quinoline}. Formation of the precursor (1) was confirmed by elemental analysis, molecular weight measurements, FT-IR, and NMR (H-1 and C-13). PdO nanoparticles (b) were obtained when unmodified PdCl2 (2) was used as precursor. XRD studies were done to determine crystal structure and phases of synthesized powders which was found to be cubic, tetragonal (Pd@PdO) and tetragonal (PdO), respectively. TEM studies were done to confirm the results obtained from XRD. HRTEM and SAED patterns confirmed the formation of core-shell nanoparticles. Crystallite size of both the samples as approximated by XRD and TEM were found to be in nanometer range. Raman spectroscopy confirmed the presence of PdO in both the samples. Surface morphologies of both the samples were evaluated by SEM. The absorption spectra of samples, (a) and (b) show the energy band gap of 1.43 and 1.89eV, respectively.