Sang-Wook Han1,Eun-Suk Jeong1,In-Hui Hwang2
Jeonbuk National University1,Argonne National Laboratory2
Sang-Wook Han1,Eun-Suk Jeong1,In-Hui Hwang2
Jeonbuk National University1,Argonne National Laboratory2
The dispersion and stability of noble-metal catalysts on transition-metal-oxide supports are considerably important for practical applications of the catalysts. Pt nanoparticles are uniformly and highly dispersed on transition-metal oxides when hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) is applied before calcination at 500 <span style="font-size:10.8333px"><sup>o</sup>C</span><b>.</b> The influence of H<sub>2</sub>O<sub>2</sub> on the dispersion and the stability of Pt nanoparticles on titania-incorporated fumed silica (Pt/Ti-FS) supports was examined using in-situ X-ray absorption fine structure (XAFS) measurements at the Pt L<sub>3</sub> and Ti K edges as well as density functional theory (DFT) calculations. The local structural and chemical properties around Pt and Ti atoms of Pt/Ti-FS with and without H<sub>2</sub>O<sub>2</sub> treatment were monitored using <i>in-situ</i> XAFS during heating from room temperature to 500 <sup>o</sup>C. XAFS revealed that the Pt nanoparticles of H<sub>2</sub>O<sub>2</sub>-Pt/Ti-FS are highly stable and that the Ti atoms of H<sub>2</sub>O<sub>2</sub>-Pt/Ti-FS support form into a distorted-anatase TiO<sub>2</sub>. DFT calculations showed that Pt atoms bond more stably to oxidized-TiO<sub>2</sub> surfaces than they do to bare- and reduced-TiO<sub>2</sub> surfaces. XAFS measurements and DFT calculations clarified that the presence of extra oxygen atoms due to the H<sub>2</sub>O<sub>2</sub> treatment plays a critical role in the strong bonding of Pt atoms to TiO<sub>2</sub> surfaces.