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<p>Preferential oxidation of CO (CO-PROX) in H<sub>2</sub>-rich streams is highly important for purifying the industrial grade H<sub>2</sub> used in proton-exchange-membrane fuel cells (PEMFC), but it is still limited to a relatively narrow operation temperature window. In this study, the trace amounts of Cu are used to modify a Pt/Al<sub>2</sub>O<sub>3</sub> catalyst. The introduced Cu<sup>2+</sup> species are atomically anchored on Pt nanoparticles through strong electrostatic adsorption. The prepared Pt–Cu/Al<sub>2</sub>O<sub>3</sub> catalyst with 0.011 wt% Cu loading achieves complete CO oxidation between 138 and 215&#xa0;°C, while the maximum CO conversion of Pt/Al<sub>2</sub>O<sub>3</sub> is only 94%. The characterization showed that the formation of the Pt–CuO<sub><i>x</i></sub> interface not only produced additional active sites for O<sub>2</sub> activation but also weakened the adsorption strength of CO due to Pt existing in an electron-deficient state. The synergy at the interface of Pt–CuO<sub><i>x</i></sub> inhibits the competitive adsorption of CO and O<sub>2</sub> on Pt nanoparticles. Compared with CO oxidation, the presence of H<sub>2</sub> in CO-PROX promotes CO oxidation through the formation of a formate (HCOO–) intermediate. The addition of Cu accelerates the HCOO– intermediate oxidation over Pt–Cu/Al<sub>2</sub>O<sub>3</sub>. The strategy of constructing metal-oxide interfacial sites sheds light on designing better catalysts for the CO-PROX reaction.</p> Graphical abstract

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Maximizing the Pt–CuOx interface by trace Cu boosts CO preferential oxidation

  • 期刊论文

  • 发表日期：

    2025年4月7日

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  • Ya-Ke Lou,
  • Zhi-Hao Chen,
  • Jia Shen,
  • Yang-Long Guo,
  • Wang-Cheng Zhan,
  • Ai-Yong Wang,
  • Núria J. Divins,
  • Jordi Llorca,
  • Li Wang,
  • Yun Guo

摘要

Preferential oxidation of CO (CO-PROX) in H2-rich streams is highly important for purifying the industrial grade H2 used in proton-exchange-membrane fuel cells (PEMFC), but it is still limited to a relatively narrow operation temperature window. In this study, the trace amounts of Cu are used to modify a Pt/Al2O3 catalyst. The introduced Cu2+ species are atomically anchored on Pt nanoparticles through strong electrostatic adsorption. The prepared Pt–Cu/Al2O3 catalyst with 0.011 wt% Cu loading achieves complete CO oxidation between 138 and 215 °C, while the maximum CO conversion of Pt/Al2O3 is only 94%. The characterization showed that the formation of the Pt–CuOx interface not only produced additional active sites for O2 activation but also weakened the adsorption strength of CO due to Pt existing in an electron-deficient state. The synergy at the interface of Pt–CuOx inhibits the competitive adsorption of CO and O2 on Pt nanoparticles. Compared with CO oxidation, the presence of H2 in CO-PROX promotes CO oxidation through the formation of a formate (HCOO–) intermediate. The addition of Cu accelerates the HCOO– intermediate oxidation over Pt–Cu/Al2O3. The strategy of constructing metal-oxide interfacial sites sheds light on designing better catalysts for the CO-PROX reaction.

Graphical abstract