The above steps were repeated for another nine times. Then, bimetallic AuPd nanoparticles were formed. The obtained sample is assigned as AuPd-AAO. Figure 1 shows a schematic representative of the reduction process. The ‘red arrows’ in the figure indicate the direction of electric field. The room-temperature operation was confirmed by thermal imaging . The same method was employed to prepare Au-AAO (0.005 mol/L HAuCl4) and Pd-AAO (0.005 mol/L PdCl2) for the comparison
purpose. Figure 2 presents images of Au-AAO, AuPd-AAO, and Pd-AAO. From the images shown in Figure 2, metallic membranes were directly obtained from the room-temperature electron reduction. However, from the transmission electron microscopy (TEM) images and X-ray diffraction (XRD) analyses, as discussed below, the metallic nanoparticle APR-246 aggregates were exactly obtained. Figure 1 Schematic representative of the electron reduction for the https://www.selleckchem.com/products/ipi-549.html synthesis of AuPd bimetallic nanoparticles. Figure 2 Images of the samples. Characterization The XRD patterns of samples were recorded on a Rigaku D/Max-2500 diffractometer (Rigaku, Shibuya-ku, Japan) (Cu-Kα radiation, λ = 0.154056 nm). Diffraction data were collected from 10° to 80° (2θ) at a scanning speed of 6°/min. The phase identification was made by comparison with the Joint Committee on Powder Diffraction Standards (JCPDSs). UV–Vis absorption spectra of samples were recorded
on Selleck MK 1775 a Beckman DU-8B UV–Vis spectrophotometer (Beckman Coulter, Inc., Fullerton, CA, USA). TEM measurements were carried out with a Philips Tecnai G2 F20 system (Philips, Amsterdam, the Netherlands) operated at 200 kV. Results and discussion The wide-angle XRD patterns of Au-AAO, AuPd-AAO (with Au/Pd molar ratio of 1/1), and Pd-AAO samples are shown in Figure 3. Au-AAO exhibits four diffraction peaks, assigned to (111), (200), (220), and
(311) of the face central cubic (fcc) structure of monometallic Au. Pd-AAO presents two diffraction peaks, assigned to (111) and (200) of the fcc structure of monometallic Pd. The bimetallic AuPd-AAO shows four diffraction peaks. However, these four peaks are observed at different 2θ, compared to monometallic Au and monometallic Pd samples. The XRD patterns of AuPd-AAO show a big peak at 38.54°, which is between pure Au (111) plane (38.184°; PDF# 04-0784) Reverse transcriptase and pure Pd (111) plane (40.118°; PDF# 46-1043). These results suggest that alloyed bimetallic nanoparticles are formed over AuPd-AAO . According to Vegard’s law , the Au/Pd molar ratio of the alloyed AuPd sample is approximately 8:2. From XPS analyses, all metal ions have been reduced. However, the peaks belonging to Au and Pd particles cannot be identified from the XRD patterns. This suggests that the formed Au and Pd particles (in addition to alloyed nanoparticles) are highly dispersed and are too small to be observed in the XRD patterns. Similar results were obtained for AuPd-AAO samples with different Au/Pd molar ratios.