The preparation of photocatalysts modified with Pt nanoparticles or [Mo3S13] 2-(={Mo3} ) clusters was described in details in our previous work. Briefly, the platinized Y-CNx and R-CNx samples were prepared using photodeposition method. For this, the Y/R-CNx powder (0.2 g) was suspended in 20 mL H2O:MeOH (9:1, v:v) containing hexachloroplatinic acid (4 mg), ultrasonicated for 1 h, bubbled with argon gas and irradiated for 30 min with a 150 W Xe-lamp equipped with a KG3 (Schott) heat filter (intensity ca. 1 sun). Subsequently, the powder was washed by centrifugation and dried overnight at 60 ºC. The {Mo3} clusters were synthesized using (NH4)2[Mo3S13] × 2H2O produced by the method described by Müller et al. Then Na2[Mo3S13] × 5H2O (={Mo3}) was obtained from (NH4)2[Mo3S13] ×2H2O by its reaction in aqueous NaOH solution under reduced pressure (20 mbar) for 2 h. The resulting dark red solution was filtered into an aqueous NaCl solution, the precipitated product was isolated by filtration, washed with 2-propanol and diethyl ether, and dried in vacuo at room temperature to give red-brown {Mo3}. The Y-CNx-{Mo3} and R-CNx-{Mo3} hybrids were synthesized through a two-step deposition process at room temperature. In a typical procedure, 20 mg of as-prepared Y/R-CNx was dispersed in 20 mL of methanol by ultrasonication for 3 h to prepare a homogenous suspension. Then, a measured amount of {Mo3} (soluble in methanol) was added and stirred for 24 h. The solid was collected by centrifugation and three times washed with methanol to remove the excess of {Mo3}. Finally, the obtained precipitates were dried at room temperature under ambient conditions yielding Y-CNx-{Mo3} and R-CNx-{Mo3}.