低温等离子体协同CeO_(2)/13X催化降解甲苯

Combing low-temperature plasma with CeO_(2)/13X for toluene degradation

低温等离子体协同催化剂技术(NTP-CAT)由于操作方便、能耗低等特点,特别适合用于工业非连续或连续消除低浓度VOCs过程。本研究发现NTP-CAT体系中CeO_(2)基催化剂更适合负载于13X载体以降解甲苯,并进一步考察CeO_(2)负载量对VOCs消除效果的影响。结果发现,NTP-CAT体系中30%CeO_(2)/13X表现出最优性能,其可降解约85%的甲苯,CO2产物选择性可达55%。表征结果也表明,Ce组分在30%CeO_(2)/13X表面仍可较好分散,而且表面的Ce^(3+)物种含量最高。O_(2)-TPD实验结果证实表面Ce^(3+)物种来源于Ce^(4+)物种的等离子体处理。而且,表面Ce^(3+)含量越高,有利于产生更多的氧物种,随后将与其周边13X吸附活化的甲苯反应。因此,甲苯降解在NTP-CAT体系中应存在分工协同机制。

The low-temperature plasma combined with catalyst technology (NTP-CAT) has feature of convenience in operation and relatively low energy consumption. It can be applied to industrial elimination of low concentration VOCs both continuous or batch. It was found the 13X supported CeO_(2) catalyst has higher efficiency to decompose toluene in NTP-CAT system, and then it is further explored the effect of CeO_(2) content on toluene degradation. The results showed that 30% CeO_(2)/13X was the best for toluene degradation using NTP-CAT, and around 85% of toluene can be decomposed with about 55% CO_(2) selectivity. The characterization results demonstrated that Ce component was dispersed relatively evenly on the surface of 13X for 30% CeO_(2)/13X. Specially, the maximum amount of Ce^(3+) was found on its surface, and the Ce^(3+) was originated from the Ce^(4+) species as deduced from the results of O_(2)-TPD. Moreover, the increased amount of Ce^(3+) was beneficial for producing more active oxygen species, which can react with the NTP-treated toluene adsorbed on the 13X. Therefore, it can be concluded that the NTP CAT system has synergic effect for toluene degradation.