In Situ Intermediates Determination and Cytotoxicological Assessment in Catalytic Oxidation of Formaldehyde : Implications for Catalyst Design and Selectivity Enhancement under Ambient Conditions

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

11 Scopus Citations
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Author(s)

  • Duckshin Park
  • Shun-Cheng Lee
  • Wingkei Ho

Detail(s)

Original languageEnglish
Pages (from-to)5230-5240
Journal / PublicationEnvironmental Science and Technology
Volume53
Issue number9
Online published16 Apr 2019
Publication statusPublished - 7 May 2019

Abstract

Formation and decay of formaldehyde oxides (CH2OO) affect the complete oxidation of formaldehyde. However, the speciation and reactivity of CH2OO are poorly understood because of its extremely fast kinetics and indirect measurements. Herein, three isomers of CH2OO (i.e., main formic acid, small dioxirane, and minor CH2OO Criegee) were in situ determined and confirmed as primary intermediates of the room-temperature catalytic oxidation of formaldehyde with two reference catalysts, that is, TiO2/MnOx-CeO2 and Pt/MnOx-CeO2. CH2OO Criegee is quite reactive, whereas formic acid and dioxirane have longer lifetimes. The production, stabilization, and removal of the three intermediates are preferentially performed at high humidity, matching well with the decay rate of CH2OO at approximately 6.6 × 103 s-1 in humid feed gas faster than 4.0 × 103 s-1 in dry feed. By contrast, given that a thinner water/TiO2 interface was well-defined in TiO2/MnOx-CeO2, fewer reductions in the active sites and catalytic activity were found when humidity was decreased. Furthermore, lethal intermediates mostly captured at the TiO2/MnOx-CeO2 surface suppressed the toxic off-gas emissions. This study provides practical insights into the rational design and selectivity enhancement of a reliable catalytic process for indoor air purification under unfavorable ambient conditions.

Research Area(s)

  • SIMPLEST CRIEGEE INTERMEDIATE, ROOM-TEMPERATURE, WATER, TIO2, HYDROPHILICITY, NANOPARTICLES, REACTIVITY, REMOVAL, VACANCY, CHARGE

Citation Format(s)

In Situ Intermediates Determination and Cytotoxicological Assessment in Catalytic Oxidation of Formaldehyde: Implications for Catalyst Design and Selectivity Enhancement under Ambient Conditions. / Li, Haiwei; Cui, Long; Lu, Yanfeng et al.
In: Environmental Science and Technology, Vol. 53, No. 9, 07.05.2019, p. 5230-5240.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review