(BMIM-NTf2, 99%) and 1-butyl-1-methylpyrrolidinium triflate
(BMPYRR-OTf, 99%) were purchased from IoLiTec and used as received.
1-Butyl-3-methylimidazolium trifluoromethanesulfonate (BMIM-OTf, 97%),
K2PtCl4 (99.9%), polyvinylpyrrolidone (PVP,
MW = 55,000), ethylene glycol (99.8%), and Fe(NO3)3•9H2O (98%) were all purchased from Sigma-Aldrich
and used as received. 1-Butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide
(BMPYRR-NTf2, 98%) was purchased from TCI Chemicals and
used as received. Acidified water at different pH levels was prepared
by diluting a nitric acid solution (Supelco, 68–70%) with deionized
(DI) water. The pH values were verified by a pH meter (Jenway 3510).