Quantum Chemistry and Computational Kinetics of the Reaction between OH Radicals and Formaldehyde Adsorbed on Small Silica Aerosol Models

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• 作者：Cristina Iuga ; Annik Vivier-Bunge ; Alfonso Herná ; ndez-Laguna ; C. Ignacio Sainz-Dí ; az
• 刊名：Journal of Physical Chemistry C
• 出版年：2008
• 出版时间：March 27, 2008
• 年：2008
• 卷：112
• 期：12
• 页码：4590 - 4600
• 全文大小：599K
• 年卷期：v.112,no.12(March 27, 2008)
• ISSN：1932-7455

文摘

Heterogeneous reactions of atmospheric volatile organic compounds (VOCs) on aerosol particles may playan important role in atmospheric chemistry. Clay particles are present in mineral dust in atmospheric aerosols,and radical reactions are thought to be heterogeneously catalyzed on them. However, the kinetics andmechanisms of adsorption and reaction of atmospheric VOCs on aerosol surfaces are not well understood. Inthis work, quantum chemical methods are used to study the reaction of OH radicals with formaldehyde adsorbedon small (SiO₄)_n cluster models, with n = 1 to 6. We show that surface adsorbed formaldehyde can react inthe presence of gas-phase OH radicals to yield surface-bound formyl radicals and water. Significant exothermicadsorption energies are found, supporting the notion that silicate surfaces are good quenchers of VOCs. Withthe models employed, the reaction appears to be less favored on the silicate surfaces than in the gas phase.The effect of the model surface on the reaction mechanism is analyzed.