The aquochloro ligand exchange between [PtCl6] 2- and H2O is an important factor to regulate the facet growth in shape-controlled synthesis of Pt nanocrystals because the electric charge and coordination structure of Pt precursor strongly influences its adsorption and reduction on Pt nanocrystal surface. In this contribution, the exposure to violet light（415 nm） is found to efficiently weaken the characteristic LMCT absorption and increase the conductance of 1.5×10 -4 mol/L K2PtCl6 aqueous solution that is fairly stable in dark aging. And, the variations of both the LMCT adsorption and the conductance are closely related with the exposure time. The 1st derivative spectra of ultraviolet absorption shows that the characteristic LMCT absorption shifts toward shorter wavelength along with the exposure which is mainly attributed to the aquochloro ligand exchange of [PtCl6] 2-.
