在Cu / TiO <sub>2</sub>气凝胶催化剂上CO氧化活化中的电子金属-载体相互作用,The Journal of Physical Chemistry C

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在Cu / TiO ₂气凝胶催化剂上CO氧化活化中的电子金属-载体相互作用
The Journal of Physical Chemistry C ( IF 3.3 ) Pub Date : 2020-09-09 , DOI: 10.1021/acs.jpcc.0c06026
Andrew J. Maynes ₁ , Darren M. Driscoll ₁ , Paul A. DeSario ₂ , Jeremy J. Pietron ₂ , Ashley M. Pennington _{2,

3} , Debra R. Rolison ₂ , John R. Morris ₁

Affiliation

一氧化碳（CO）氧化不仅是重要的工业反应，而且是研究涉及新催化剂设计的反应动力学的有用模型系统。在这项工作中，我们使用CO氧化来探测Cu纳米颗粒和TiO ₂气凝胶载体之间的金属-载体相互作用。我们利用填充床反应器论证了Cu / TiO ₂气凝胶催化剂在463 K以上的温度下对CO氧化的活性。原位红外光谱法显示反应主要通过Cu辅助的Mars-van-Krevelen型进行机制。结果表明，CO^会使Ti ^4+的位点还原，生成Ti ³⁺氧空位附近的位置。晶格氧萃取似乎伴随着电荷从低功函铜纳米粒子到TiO ₂载体的转移，这是通过吸附式CO的可变温度红外光谱研究证明的。在有和没有铜的情况下，气凝胶中的Ti ⁴⁺位点。TiO ₂上的Cu颗粒将与Ti ⁴⁺结合的CO的振动频率降低了3 cm ^–1使结合焓增加7 kJ / mol。催化过程中氧化态循环的红外光谱探针有助于在Cu / TiO ₂气凝胶上发展整体CO氧化反应机理。

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Electronic Metal–Support Interactions in the Activation of CO Oxidation over a Cu/TiO2 Aerogel Catalyst

Carbon monoxide (CO) oxidation is not only an important industrial reaction but also a useful model system for investigations into reaction dynamics involving new catalyst designs. In this work, we use CO oxidation to probe the metal−support interactions between Cu nanoparticles and a TiO₂ aerogel support. We utilized a packed-bed reactor to demonstrate the activity of a Cu/TiO₂ aerogel catalyst for CO oxidation at temperatures above 463 K. In situ infrared spectroscopic methods revealed that the reaction proceeds primarily by a Cu-assisted Mars-van-Krevelen type mechanism. Results indicate that Ti⁴⁺ sites are reduced by CO to generate Ti³⁺ sites adjacent to oxygen vacancies. Lattice oxygen extraction appears to be accompanied by interfacial charge transfer from lower work function copper nanoparticles to the TiO₂ support, as evidenced by variable-temperature infrared spectroscopic studies of adsorbed CO. The charge transfer is evidenced by differences in the nature of CO bound to Ti⁴⁺ sites within aerogels in the presence and absence of Cu. The Cu particles on the TiO₂ support lower the vibrational frequency for CO bound to Ti⁴⁺ sites by 3 cm^–1 and increase the binding enthalpy by 7 kJ/mol. Infrared spectroscopic probes of oxidation state cycling during catalysis contribute toward the development of an overall CO oxidation reaction mechanism on the Cu/TiO₂ aerogel.

更新日期：2020-10-02

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