UnTied Universe

2. Experimental
The stock solution of palladium precursor about 0.1127 M was prepared in accordance with our previous study [19]. Then, appreciable volume of this YM155 solution was diluted in deionized water in order to reach expected concentration. Chloride ions amount in the solution was adjusted with NaCl addition (p.a., POCH). Ionic strength was kept with NaClO4 (p.a., Koch-Light Laboratories Ltd).
The aqueous solution of l-ascorbic Acid (Sigma-Aldrich, Germany) was prepared via dissolution of proper amount of reductant in deionized water.
The kinetic curves with fivefold iteration were registered by Spectrophotometer Stopped-flow (Applied Photophysics, UK). The level of turbidity of obtained solution containing palladium nanoparticles was collected by UV-Vis spectrophotometer (Shimadzu, Japan). Both spectrophotometers are working in the wavelength range 190-900 nm. In order to measure the size and size distribution of obtained palladium particles, Nanozetasizer Nano-ZS (Malvern, UK), was used.
3. Results and discussion
3.1. Experimental conditions
Kinetics of nucleation and growth of palladium nanoparticles was investigated under different conditions of precursor, reductant and chloride ions initial concentration, and also at different temperature and ionic strength (see Table 1).
3.2. The property of reagents (speciation diagrams)
3.2.1. Palladium(II) chloride complex ions
Values of equilibrium constants are given in our previous paper [19]. From these Eqs. (4a), (4b), (4c) and (4d) one can conclude that with decreasing pH of the solutions, the hydrolysis process is reversed, and palladium(II) chloride complex ions are more stable, e.g. for pH below 2, in the solution is c.a. 100% of PdCl42- (see, Fig. 1). The chloride ions present in the solution also play an important role in hydrolysis (see equations describing equilibrium constants K1-4) and it can be assumed, that with the increasing amount of Cl? ions in the solution, the stability of Pd(II) chloride complex is also increasing (the equilibrium is moved to the left). In order to demonstrate these changes, two stability diagrams were calculated and shown in Fig. 1.