Sihor Marcel, Kočí Kamila, Matĕjová Lenka, Reli Martin, Ambrožová Nela, Pavlovský Jiří, Capek Libor, Obalová Lucie
J Nanosci Nanotechnol. 2015 Sep;15(9):6833-9. doi: 10.1166/jnn.2015.10877.
The aim of this study was to remove ammonia from an aqueous solution by its decomposition to valuable products such as H2 and harmless N2 under UV light. The decomposition of ammonia by photocatalytic process represents an emerging and interesting way of its removal since beside the need of its reduction from the drinking and wastewaters with the respect to its negative impact on human and mammals health, it can lead to generation of hydrogen as an alternative fuel. A laboratory-synthesized Pt/TiO2-ZrO2 photocatalyst was studied and its photocatalytic activity was compared with the activity of commercial TiO2 Evonik P25. The Pt/TiO2-ZrO2 photocatalyst was prepared by combining a sol-gel process controlled within reverse micelles of nonionic surfactant Triton X-114 in cyclohexane, impregnation under vacuum and calcination. Explored photocatalysts were characterized by organic elementary analysis, nitrogen physisorption, XRD, FESEM and UV-Vis spectroscopy. The real platinum content in the Pt/TiO2-ZrO2 photocatalyst was determined by ICP-MS. The photocatalytic decomposition of ammonia was investigated in the time range of 0-12 h. During the first two hours the generation of hydrogen was almost negligible. The generation of hydrogen increased after 4 h of irradiation. Based on time dependences of ammonia decomposition the kinetic rate constants for Pt/TiO2-ZrO2 and TiO2 Evonik P25 photocatalysts were calculated. The ammonia photocatalytic decomposition was described well by the first order kinetic equation. The photocatalytic ammonia decomposition over the platinized TiO2-ZrO2 photocatalyst was proving 2 times higher photocatalytic performance than Evonik P25 (1241 μmol/g(cat) and 665 μmol/g(cat), respectively).
本研究的目的是通过在紫外光下将氨分解为有价值的产物（如H2）和无害的N2，从而从水溶液中去除氨。通过光催化过程分解氨是一种新兴且有趣的去除氨的方法，这是因为除了需要减少其在饮用水和废水中的含量以降低其对人类和哺乳动物健康的负面影响外，该过程还能产生氢气作为替代燃料。对实验室合成的Pt/TiO2-ZrO2光催化剂进行了研究，并将其光催化活性与商用TiO2赢创P25的活性进行了比较。Pt/TiO2-ZrO2光催化剂是通过将非离子表面活性剂Triton X-114在环己烷的反胶束中控制的溶胶-凝胶过程、真空浸渍和煅烧相结合来制备的。通过有机元素分析、氮物理吸附、XRD、FESEM和紫外-可见光谱对所研究的光催化剂进行了表征。通过ICP-MS测定了Pt/TiO2-ZrO2光催化剂中实际的铂含量。在0-12小时的时间范围内研究了氨的光催化分解。在前两小时内，氢气的产生几乎可以忽略不计。照射4小时后氢气的产生量增加。根据氨分解的时间依赖性，计算了Pt/TiO2-ZrO2和TiO2赢创P25光催化剂的动力学速率常数。氨的光催化分解可以用一级动力学方程很好地描述。铂负载的TiO2-ZrO2光催化剂上的光催化氨分解性能比赢创P25高两倍（分别为1241 μmol/g（催化剂）和665 μmol/g（催化剂））。
