Independent Control of Metal Cluster and Ceramic Particle Characteristics During One-step Synthesis of Pt/TiO_2

Rapid quenching during flame spray synthesis of Pt/TiO 2 (0–10 wt% Pt) is demonstrated as a versatile method for independent control of support (TiO 2 ) and noble metal (Pt) cluster characteristics. Titania grain size, morphology, crystal phase structure, and crystal size were analyzed by nitrogen adsorption, electron microscopy and x-ray diffraction, respectively, while Pt-dispersion and size were determined by CO-pulse chemisorption. The influence of quench cooling on the flame temperature was analyzed by Fourier transform infrared spectroscopy. Increasing the quench flow rate reduced the Pt diameter asymptotically. Optimal quenching with respect to maximum Pt-dispersion (∼60%) resulted in average Pt diameters of 1.7 to 2.3 nm for Pt-contents of 1–10 wt%, respectively.

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