Reaction Mechanism of the Multiple-Electron Oxygen Reduction Reaction on the Surfaces of Gold and Platinum Nanoparticles Loaded on Titanium(IV) Oxide

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• 作者：Hisayoshi Kobayashi ; Miwako Teranishi ; Ryo Negishi ; Shin-ichi Naya ; Hiroaki Tada
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2016
• 出版时间：December 15, 2016
• 年：2016
• 卷：7
• 期：24
• 页码：5002-5007
• 全文大小：397K
• ISSN：1948-7185

文摘

Au and Pt nanoparticles with varying mean particle size and comparable loading amounts were loaded on the surface of TiO₂ (Au/TiO₂ and Pt/TiO₂, respectively). The photocatalytic activities of Au/TiO₂ and Pt/TiO₂ for the oxygen reduction reaction (ORR) in an aerated aqueous solution containing 4% ethanol were compared under ultraviolet-light irradiation at 298 K. The initial rate of H₂O₂ generation (or H₂O₂ formation rate) in the Au/TiO₂ system is much greater than that in the Pt/TiO₂ system regardless of the metal particle size. To clarify the origin for the striking difference in the activity, the photocatalytic ORR on the model slabs (M₂₈/(TiO₂)₃₂ and M₅₀/(TiO₂)₉₆, M = Au and Pt) was simulated by density functional theory (DFT) calculations taking the solvation effect into consideration. The DFT calculations clearly show that regardless of the cluster size, H₂O₂ formation more easily occurs structurally and energetically for the Au/TiO₂ system, whereas H₂O is generated with the O–O bond cleavage in the Pt/TiO₂ system.