An investigation of structural properties of monometallic (Ag, Pd) and bimetallic (Ag@Pd) nanoparticles growth on macro porous silicon

Monometallic nanoparticle Ag, Pd and bimetallic nanoparticles Ag@Pd with well-controlled morphology, uniform size, and regular alloy structure were produced by an ion reduction process with dangling bonds of porous layer Psi to fabricate monometallic(Ag, Pd) /macro Psi and bimetallic (Ag@Pd) /macro Psi hetro-structure. Psi substrate was synthesized by Photo-electrochemical etching (PECE) with a laser power density (15 mW/cm2), monometallic structure has been synthesized by dipping fresh Psi sample in salt solutions (AgNO3 and PdCl2) for about 5 min, while bimetallic nanoparticles was synthesized by dipping Psi in mix solution at a ratio (1:1) for about 2 and 4 min. The monometallic and bimetallic nanoparticles were confirmed by scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive X-ray analysis (EDS). The results show that the composition of Ag@Pd alloy nanoparticles was uniformly dispersed and well-defined distribution on Psi surface; having an average size of (8 to 7.1) nm is smaller than monometallic nanoparticles sizes. The lower Ag@PdNPs size and therefore a higher specific surface area (S.S.A) were obtained for about (71 to 63.8) m2/gm, these high specific area is most important for different application such as: chemicals or gas sensing.