Abstract Manganese oxide/titanium dioxide (MnOx/TiO2, or MnTi) catalyst prepared by an ultrasound-assisted impregnation method was employed for simultaneous nitrogen oxide (NO) reduction and elemental mercury (Hg0) oxidation under a simulated selective catalytic reduction (SCR) atmosphere. An NO reduction rate of 83% and Hg0 oxidation rate of 96% were simultaneously achieved at a relatively low temperature of 200 °C. Ammonia (NH3) as a reducing agent in the NO-SCR process was systematically investigated for its effect on Hg0 oxidation. The results showed that NH3 inhibited Hg0 oxidation over the low-temperature MnTi catalysis process. In the presence of NH3, competitive adsorption between NH3 and Hg0 on the MnTi catalyst was partly responsible for the weakening Hg0 oxidation. NH3 consumed surface oxygen (O2) on the MnTi catalyst, which also resulted in lower Hg0 oxidation rate, especially in the absence of gas phase O2 in the flue gas. More importantly, oxidized mercury was reduced by NH3 to form Hg0 with the aid of NO, i.e., the combined presence of NO and NH3 induced the reduction of oxidized mercury, and hence partially offset Hg0 oxidation. The effects of individual SCR gases, such as O2, NO, and the combinations, on Hg0 oxidation were also elaborated.

中文翻译：

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NH 3 在低温MnO x /TiO 2 SCR催化剂上抑制汞氧化

摘要 采用超声辅助浸渍法制备的氧化锰/二氧化钛 (MnOx/TiO2, or MnTi) 催化剂在模拟选择性催化还原 (SCR) 气氛下同时进行氮氧化物 (NO) 还原和元素汞 (Hg0) 氧化。 . 在 200 °C 的相对较低的温度下，同时实现了 83% 的 NO 还原率和 96% 的 Hg0 氧化率。系统研究了氨 (NH3) 在 NO-SCR 过程中作为还原剂对 Hg0 氧化的影响。结果表明，NH3 在低温 MnTi 催化过程中抑制了 Hg0 氧化。在 NH3 存在下，MnTi 催化剂上 NH3 和 Hg0 之间的竞争吸附是减弱 Hg0 氧化的部分原因。NH3 消耗了 MnTi 催化剂上的表面氧 (O2)，这也导致了较低的 Hg0 氧化率，尤其是在烟气中不存在气相 O2 的情况下。更重要的是，氧化汞在 NO 的帮助下被 NH3 还原形成 Hg0，即 NO 和 NH3 的共同存在诱导氧化汞的还原，因此部分抵消了 Hg0 氧化。还详细阐述了单个 SCR 气体（如 O2、NO 及其组合）对 Hg0 氧化的影响。