Figure 2.

Detailed structural characterizations of fast and slow cryogenic hydrolysates. (a) UV-vis absorption spectra of (NH₄)₂PtCl₆ aqueous solutions (0.1 mg ml⁻¹) with different pH values (from 0 to 14), clearly indicating that the [PtCl₆]^2- ion undergoes deep hydrolysis with increasing pH values. (b, c) UV-vis adsorption spectra of fast cryoequilibrium hydrolysates (b) and slow cryogenic hydrolysates (c) obtained from the (NH₄)₂PtCl₆ solution with different pH values (from 0 to 14), showing that the hydrolysates at the different dynamic equilibrium states could be well maintained through fast cryogenic treatment. (d) XRD patterns of fast cryoequilibrium hydrolysates and slow cryogenic hydrolysates confirm the existence of NH₄Cl in the obtained fast cryoequilibrium hydrolysates.