Green Synthesis and Characterization of Platinum Nanoparticles and Their Application in Chemiluminescence Reactions
Platinum nanoparticles (Ptnps) are widely used in the biomedical industry. [8,21] They have been studied because of their antioxidant, antimicrobial, and anticancer properties.[3,13,19] Pt has proven to be a good catalyst for many reactions.[4,7, 23] With so much pollution in the world, we wanted to see if there was a way to produce Ptnps with as little negative environmental impact as possible. Green synthesis methods are preferred over the traditional synthesis methods as they minimize environmental pollution.[6,8] Using green chemistry, we wanted to attempt to produce Ptnps with naturally occurring materials.
In the preparation of Ptnps, different Pt salts are used. In this work, we report the synthesis of Ptnps using H2PtCl6 and K2PtCl6 salts and a green source. We obtained our Chloroplatinic acid hydrate (H2PtCl6) from Sigma-Aldrich and we obtained our Potassium hexachloroplatinate (IV) (K2PtCl6), from Strem Chemicals, INC.
The Pt salt and the green source were placed in a shaking incubator for 4 and 72 hours at room temperature. The synthesized Ptnps were characterized using UV-Visible spectroscopy, Fourier Transform Infrared Spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The average size of the particles was estimated using dynamic light scattering measurements using the zetasizer and the redox properties were measured using cyclic voltammetry.
The results show that Ptnps are formed using both salts in both incubation periods. The UV-Visible Spectrum results show peaks that indicate the formation of Pt at both incubation periods in both Pt salts. We notice the peaks are more intense in the samples that were in the shaking incubator for 72 hours as opposed to the samples that were incubated for four hours. The K2PtCl6 salt shows a more intense peak than the H2PtCl6 salt in the 72-hour incubation period and both salts show similar peak intensity when held in the shaking incubator for four hours.
The Dynamic light scattering results show that H2PtCl6 salt has similar Zaverages for both incubation periods. K2PtCl6 salt that was incubated for four hours shows smaller Z-averages to the H2PtCl6 salt held at both incubation periods. K2PtCl6 salt that was incubated for 72 hours had at least 1/3 lower Z-averages. This could be due to in K2PtCl6 salt the potassium ion is preventing the aggregation.
The cyclic voltammetry results show that the oxidation and reduction peaks vary between salts, time, and our naturally occurring materials. The SEM/EDS results show the presence of Pt for both salts at both incubation periods. When analyzing our results, we observed the amount of Pt present was higher when the Pt salt was incubated for 72 hours versus four hours. The Fourier Transform Infrared Spectroscopy results for both
salts and incubation periods show a broad peak in the functional group region between 2500 and 3550. Peaks in this range are indications of the presence of OH groups. There is also another peak between 2850 and 3300, this peak is an indication of the CH group. The CH stretch intensity varies between salts and the naturally occurring material used.
In this research, we demonstrated the synthesis of Ptnps using a green method. The results show that Ptnps can be produced in an environmentally friendly way using both H2PtCl6 and K2PtCl6 salts. We can assume K2PtCl6 salt may be a better salt to use when producing Pt because the results from multiple experiments show it was possibly less aggregated than that of the Ptnps produced with the H2PtCl6 salt. The synthesized Ptnps when used in the chemiluminescence reaction of luminol show that it enhanced the activity. In future work, we plan on using these in lateral flow assay (LFA) experiments that are used in point of care testing.