Temperature-programmed reduction study on carbon-supported platinum-gold alloy catalysts.
Alloy catalysts of Pt-Au/C with different Pt/Au ratios were prepared by the precipitation-deposition of metal chlorides and reduced by H(2) at 470 K. The surface composition of alloy crystallites deposited on the prepared catalysts was characterized by a technique of temperature-programmed reduction (TPR). In the characterization, O(2) was chemisorbed on the reduced catalysts and the chemisorbed O(2) was reduced by TPR. A low-temperature routine (LT) in the temperature range between 120 and 430 K was used for the TPR characterization. Monometallic catalysts of Au/C and Pt/C showed a reduction peak in the LT-TPR at reduction temperature (T(r))=145 and 240 K, respectively. T(r) from alloyed catalysts fell in the range and increased monotonously with their Pt/Au ratios. Interior Pt atoms in deposited alloy particles tended to segregate toward their surface during oxidation treatment at elevated temperatures.
Institute of Materials Science and Engineering, National Central University, No. 300, Jhongda Road, Chungli, Taoyuan 320, Taiwan.
Kuan-Wen
KW
Wang
Chuin-Tih
CT
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