Visible light photocatalytic activities of nitrogen and platinum-doped TiO₂: Synergistic effects of co-dopants

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• 作者：Wooyul Kim ; Takashi Tachikawa ; Hwajin Kim ; Narayanan Lakshminarasimhan ; Palanichamy Murugan ; Hyunwoong Park ; Tetsuro Majima ; Wonyong Choi
• 关键词：Visible light photocatalysis ; Titanium dioxide ; Dopants ; Band structure ; Photooxidation and photoreduction
• 刊名：Applied Catalysis B: Environmental
• 出版年：5 April, 2014
• 年：2014
• 卷：147
• 期：Complete
• 页码：642-650
• 全文大小：1957 K

文摘

The visible light photocatalytic activity of nitrogen doped TiO₂ (N-TiO₂) was enhanced with co-doping of Pt ions for the oxidative and reductive degradation of model substrates in gaseous and aqueous phases. The synthesized samples were characterized by various techniques (diffuse reflectance UV-Vis, XPS, XRD, FT-IR, HR-TEM, EDX and laser flash photolysis spectroscopy). The co-doping of N and Pt of TiO₂ (Pt,N-TiO₂) significantly enhanced the degradation of acetaldehyde (gas phase), and trichloroacetate (TCA) (aqueous phase), and the reduction of Cr(VI) (aqueous phase) under visible light (位 > 420 nm). The observed visible light photocatalytic activity of Pt,N-TiO₂ was markedly higher than the singly-doped TiO₂ (Pt-TiO₂ or N-TiO₂). A time-resolved diffuse reflectance (TDR) study found that the presence of the different oxidation states of Pt (2+ and 4+) plays a crucial role in the charge trapping and transfer dynamics in Pt-TiO₂. The TDR study of Pt,N-TiO₂ further revealed that the synergistic effect of co-doping is attributed to the combined contribution of each dopant. Finally, the first principle calculations for the doped TiO₂ suggested that the electronic interaction of Pt and N in TiO₂ facilitates the charge carrier mobility and reduces the undesired recombination, leading to enhanced photocatalytic activity.