To verify theoretical prediction, the Chini clusters were synthesised with diferent pH conditions and deposited on TiO2, to check their activity in photocatalytic hydrogen generation. The nuclearity of the obtained systems was assigned using UV-Vis spectroscopy: the samples synthesised at pH = 13 contain [Pt3(CO)6-H2]4 The results of the photocatalytic experiments are shown in Figure . A substantial rise in the H2 generation activity is observed when the Chini-TiO2 composites are used instead of bare TiO2. This points out the activity of the Chini clusters in the H2 generation reaction. The analysis of the obtained data reveals two trends.