| Summary: | In this contribution, four different commercial TiO<sub>2</sub> catalysts (P25, P90, PC105, and PC500) were screened for the photocatalytic production of hydrogen using ethanol as the sacrificial agent. The physico-chemical properties of the TiO<sub>2</sub> powders were characterized by using different methods. The photocatalysts mainly vary in the ratio of anatase and rutile phases, and in the surface area. It was found that the photocatalytic activity is governed by the surface area of the photocatalyst. Pure TiO<sub>2,PC500</sub> showed the best performance, and in comparison to P25, the activity was more than twenty times higher due to its high surface area of about 270 m<sup>2</sup> g<sup>−1</sup>. For further improvement of the photocatalytic activity, platinum nanoparticles (PtNPs) were immobilized onto TiO<sub>2,PC500</sub> using two methods: a colloidal approach and a photodeposition method. For the reduction of the platinum salt precursor in the colloidal approach, different green reducing agents were used in comparison to ascorbic acid. The obtained platinum nanoparticles using natural reductants showed a higher photocatalytic activity due to the formation of smaller nanoparticles, as proven by transmission electron microscopy (TEM). The highest activity was obtained when mangosteen was used as the green reducing agent. Compared to ascorbic acid as a classical reducing agent, the photocatalytic activity of the Pt@TiO<sub>2,PC500</sub> prepared with mangosteen was about 2–3 times higher in comparison to other as-prepared photocatalysts. The Pt@TiO<sub>2,PC500</sub> catalyst was further studied under different operating conditions, such as catalyst and sacrificial agent concentration.
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