Preparation of platinum nanoparticles on TiO2 from DNA-protected particles

• Preparation of supported catalysts by using DNA as a protecting polymer.
• Pt/TiO2 catalysts with high Pt dispersion were obtained.
• The catalysts were effective for CO oxidation.

This paper reports on preparation methods for TiO2-supported Pt catalysts (Pt/TiO2) using colloidal DNA-protected Pt particles. Pt nanoparticles with the average size of 1.4 nm were prepared by reduction of H2PtCl6 with NaBH4 in aqueous solution in the presence of salmon sperm deoxyribonucleic acid (DNA). The Pt particles were deposited on TiO2 with high dispersion by mixing the TiO2 powder with the Pt particles in the solution. The DNA polymer was completely removed from the Pt/TiO2 surface by centrifugation and washing processes. XAFS studies revealed that the DNA-stabilized Pt particles mainly consisted of Pt oxides. The Pt dispersion on TiO2 did not depend on the amount of DNA in colloidal Pt dispersion, whereas the Pt loading level increased with the increase in the DNA amount. The Pt/TiO2 catalysts after oxidation–reduction treatment have both high oxidizability and reducibility, and the catalysts exhibited higher activity for CO oxidation than the PtTiO2 catalyst prepared by impregnation technique.

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