Facet-dependent photocatalytic NO conversion pathways predetermined by adsorption activation patterns

Peng Chen, Yanjuan Sun, Hongjing Liu, Ying Zhou, Guangming Jiang, S. C. Lee, Yuxin Zhang, Fan Dong

Research output: Journal article publicationJournal articleAcademic researchpeer-review

21 Citations (Scopus)

Abstract

Photocatalysts with different exposed facets generally exhibit different physicochemical properties, but the underlying mechanism has not been revealed. In this study, we synthesized nanoflake-assembled flower-like Bi 2 O 2 CO 3 and homodisperse nanoflakes Bi 2 O 2 CO 3 with exposed {110} and {001} facets (110-BOC and 001-BOC), respectively, to probe the activation and reaction mechanism of facet-dependent reactants. The results showed that Bi 2 O 2 CO 3 with exposed {001} facets exhibited superior photocatalytic activity for photocatalytic abatement of NO in the air in comparison with 110-BOC. According to the combined results of ESR spectra and DFT calculation, the superior photocatalytic activity of 001-BOC stemmed from its enhanced capability to activate the reactants (O 2 and H 2 O), which facilitated the formation of reactive radicals to participate in the photocatalytic NO oxidation. Most significantly, the time-dependent in situ DRIFTS spectra and DFT simulation results reveal that the adsorption activation of pollutants and desorption mechanisms of products were different for 110-BOC and 001-BOC in photocatalytic NO oxidation. Due to the differences in the atomic arrangement on the {110} and {001} facets, 001-BOC enabled the transformation of NO into NO - or cis-N 2 O 2 2- during adsorption activation, while 110-BOC induces the adsorption activation of NO into NO + or N 2 O 3 . The {001} facet of Bi 2 O 2 CO 3 could promote the oxidation of intermediates to final products (NO 3 - ) and enhance NO 3 - desorption. These different adsorption activation patterns on {110} and {001} facets essentially predetermined the facet-dependent conversion pathways of photocatalytic NO oxidation on different facets. The findings of this work would have critical implications for the understanding of the facet-dependent reaction mechanism and the design of novel efficient catalysts.

Original languageEnglish
Pages (from-to)2366-2373
Number of pages8
JournalNanoscale
Volume11
Issue number5
DOIs
Publication statusPublished - 7 Feb 2019

ASJC Scopus subject areas

  • Materials Science(all)

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