Reaction Mechanism of Ammonia Decomposition to Nitrogen and Hydrogen over Metal Loaded Titanium Oxide Photocatalyst
Reaction Mechanism of Ammonia Decomposition to Nitrogen and Hydrogen over Metal Loaded Titanium Oxide Photocatalyst
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DOI：
10.1021/jp209795t
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发表时间：
2012-02
影响因子：
3.7
通讯作者：
H. Yuzawa;Takamasa Mori;H. Itoh;H. Yoshida
中科院分区：
文献类型：
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作者：
H. Yuzawa;Takamasa Mori;H. Itoh;H. Yoshida
通过各种反应试验，结合ESR和FT-IR光谱，研究了载铂氧化钛光催化剂上氨分解为氮气和氢气的反应机理。氧化钛上的光形成孔氧化NH3以形成酰胺自由基（·NH 2）和质子。酰胺基产生肼（N2 H4），它可以进一步分解形成氮和氢。另一方面，光成形电子通过氧化钛的导带迁移到铂纳米颗粒，并还原质子以产生氢。具有较大功函数的金属，如铂，可以提供更有效的助催化剂。在该光催化反应体系中，水分子是反应连续进行的必要条件。原位FT-IR研究表明，水限制了非活性副产物铵离子（NH 4+）在氧化钛表面上的积累。
The reaction mechanism of ammonia decomposition to nitrogen and hydrogen over platinum loaded titanium oxide photocatalyst was investigated through various reaction tests, as well as ESR and FT-IR spectroscopies. The photoformed hole on the titanium oxide oxidizes NH3 to form amide radical (•NH2) and proton. The amide radicals produce hydrazine (N2H4), and it can be further decomposed to form nitrogen and hydrogen. On the other hand, the photoformed electron migrates to platinum nanoparticles through the conduction band of the titanium oxide and reduces the proton to yield hydrogen. The metals with larger work function, such as platinum, can provide more effective cocatalysts. In this photocatalytic reaction system, water molecules were essential for the continuous reaction progress. An in situ FT-IR study clarified that water restricted the accumulation of inactive byproduct, ammonium ion (NH4+), on the titanium oxide surface.