کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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47212 | 46464 | 2010 | 7 صفحه PDF | دانلود رایگان |
Batch experiments were conducted to study the photocatalytic oxidation of aqueous ammonia (NH3/NH4+) over platinized titanate nanotubes (platinized TNTs). The reaction kinetics of NH3/NH4+ oxidation is considerably enhanced by the platinization of TNTs. The observed rate constant (kobs) for NH3/NH4+ oxidation over platinized TNTs was 1.69 × 10−2 min−1, while the unamended TNTs gave a kobs = 1.23 × 10−3 min−1. The selectivity of nitrogen gas (N2) from degraded NH3/NH4+ increased with platinum loading to 87.8% after 1 h photocatalysis. In contrast, NH3/NH4+ to nitrate (NO3−) conversion was low due to a large NH3/NH4+ to nitrite (NO2−) energy barrier. High-resolution transmission electron microscopy shows that platinum deposits are formed primarily on the internal surface of the hollow structure of TNTs instead of being deposited on the external surface of TNTs. Based on the analysis of X-ray photoelectron spectroscopy, a mechanism is proposed in which N2 is produced from the NH3/NH4+ adsorbed on platinum deposits while NO2−/NO3− is formed from the NH3/NH4+ adsorbed on titanate sites.
Figure optionsDownload as PowerPoint slideResearch highlights▶ Pt particles can be deposited either on the internal and external surface of TNTs. ▶ The light-shielding effect owing to the platinization is not apparent for TNTs. ▶ NH3/NH4+ over platinized TNTs can be potentially photo-transformed into N2.
Journal: Applied Catalysis B: Environmental - Volume 99, Issues 1–2, 31 August 2010, Pages 74–80