Cell Reports Physical Science (Dec 2021)

Light-promoted activation of oxygen and carbon monoxide for low-temperature catalytic oxidation

  • Chenxi Dong,
  • Xupeng Zong,
  • Ziwen Liu,
  • Lijuan Niu,
  • Zhao Zhao,
  • Li An,
  • Dan Qu,
  • Xiayan Wang,
  • Zaicheng Sun

Journal volume & issue
Vol. 2, no. 12
p. 100678

Abstract

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Summary: Molecular oxygen (O2) activation is a critical step in the low-temperature catalytic oxidation of carbon monoxide (CO). Photocatalysis is a facile way to activate O2 to superoxide radicals under mild conditions. Photothermal catalysis, which integrates the photocatalysis of semiconductors and the thermocatalysis of noble metals, has arisen as an appealing strategy to achieve low-temperature catalytic oxidation. Here, we report that Pd/PdO/CeO2 shows that the temperature of 90% CO conversion dropped by 30°C–50°C under irradiation. The apparent activation energy reduces from 64.6 kJ ⋅ mol−1 to 44.6 kJ ⋅ mol−1. Pd/PdO/TiO2 and Pd/PdO/Al2O3 are prepared and compared to understand the underlying mechanism. The results reveal that photocatalysis is vital in lowering the apparent activation energy besides the photothermal effect. The photo-generated electrons promote O2 activation to generate the superoxide anion. The hole can activate the adsorbed CO on the PdO. These active species are beneficial for lowering the CO oxidation temperature.

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