Low Pt Loading High Catalytic Performance of PtFeNi/Carbon Nanotubes Catalysts for CO Preferential Oxidation in Excess Hydrogen I: Promotion Effects of Fe and/or Ni
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The commercial carbon nanotubes (CNTs-o) and purified carbon nanotubes (CNTs-p) have been utilized to prepare Pt(FeNi)/CNTs catalysts for CO preferential oxidation (PROX) in H2 rich stream. The 3 wt%Pt0.41 %Fe 0.35 %Ni/CNTs-p catalyst after activation at 500 °C in H2 can almost completely remove CO at 6 °C in feed gas containing 1 % CO, 0.5 % O2 (volume ratio) and H2 balance. CNTs-o supported 3 wt% Pt can also remove CO almost completely at room temperature, after activation at 500 °C in the feed gas. And this catalyst can keep high activity, high selectivity and high stability for PROX of CO at room temperature. These catalysts are the most effective catalysts for PROX of CO with much lower Pt loading until so far. H-TPR, XRD, HRTEM and reaction results indicate that the Fe and/or Ni precursors have been reduced to metallic state after activation in H2 which can be oxidized to coordinatively unsaturated FeOx and/or NiOx active species after exposure to feed gas. XPS data point out that over oxidation of Fe and Pt species will deactivate the catalysts seriously. The high catalytic performance is mainly due to the promotion effects of in situ formed coordinatively unsaturated FeOx and/or NiOx species and the unique properties of CNTs.
KeywordsLow Pt loading Fe/Ni promoted Pt catalysts Carbon nanotubes CO preferential oxidation (PROX)
The authors gratefully thank Dr. Xinhe Bao and Dr. Xiulian Pan at Dalian Institute of Chemical Physics, Chinese Academy of Sciences, for their enthusiastic supervision and helpful discussions. This work is financially supported by the Natural Science Foundation of Guangdong Province, China (Grant No. S2011010000737), the Doctoral Fund of Ministry of Education of China (20110172120017), the Fundamental Research Funds for the Central Universities (Grant No. 2011zm 0048), and the Key Laboratory of Renewable Energy and Gas Hydrate, Chinese Academy of Sciences (No. Y007K1).
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