Polyhedral Pt vs. spherical Pt nanoparticles on commercial titanias: Is shape tailoring a guarantee of achieving high activity?

• The optical properties of P25 based composites are Pt-shape dependent.
• The phenol and methyl-orange degradation is shape and base catalyst dependent.
• Fine-tuning of the degradation intermediates is possible via Pt morphology.
• Kinetics of oxalic acid degradation was independent from the shape of Pt.
• The H2 production was efficient in the case of spherical Pt with high index facets.

As shape tailoring is gaining more attention in the field of photocatalysis, exploration of the impact of noble metal (Pt) nanoparticles’ morphology on the activity of TiO2–Pt nanocomposites is inevitable. Spherical and polyhedral Pt nanoparticles have been synthesized by chemical reduction, while Aldrich anatase, Aldrich rutile, and Aeroxide P25 were used as base photocatalysts. The nanocomposites were analyzed using DRS, XRD, and HRTEM to uncover morphological, optical, and structural peculiarities of the composite photocatalysts. The importance of the Pt nanoparticles’ geometry was proven at three levels: (i) UV light-driven photodegradation of three model pollutants: phenol, methyl orange, and oxalic acid; (ii) the primary degradation intermediates’ evolution profile in the case of phenol degradation; and (iii) photocatalytic H2 production.

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