Manganese oxide octahedral molecular sieve (OMS-2) with cryptomelane structure synthesized by a solvent-free method was employed to oxidize gaseous elemental mercury (Hg⁰) in coal combustion flue gas for the first time. Brunauer-Emmett-Teller (BET) surface area analysis, X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectra, H₂ temperature-programmed reduction (H₂-TPR) and X-ray photoelectron spectroscopy (XPS) measurement were employed to characterize the catalyst. The OMS-2 with large surface area and abundant pores presented excellent Hg⁰ oxidation performance at a wide temperature range of 100–250 °C. At the optimal operating temperature of 150 °C, 93% Hg⁰ oxidation efficiency was obtained under a gas hourly space velocity as high as 1,350,000 h⁻¹. Hg⁰ oxidation on OMS-2 catalyst was supposed to follow the Mars-Maessen mechanism, where the gaseous Hg⁰ was firstly adsorbed on the OMS-2 catalyst surface to form adsorbed Hg⁰, and then the adsorbed Hg⁰ was oxidized by the lattice oxygen over catalyst surface to form mercury oxide (HgO). Both HCl and NO in the flue gas promoted Hg⁰ oxidation mainly due to the formation of active species like Cl∗, NO₂, which reacted with Hg⁰ to form volatile mercury species. SO₂ inhibited the Hg⁰ oxidation by reducing the adsorbed HgO into gaseous Hg⁰ or generating sulfate on the catalyst surface. Water vapor also played an inhibitive role in Hg⁰ oxidation. However, the SO₂ and H₂O resistance of OMS-2 catalyst was much superior compared to other commercial catalysts, which makes it promising for industrial application. This knowledge is beneficial for developing economical and efficient Hg⁰ oxidation catalysts for coal-fired power plants.

采用无溶剂法合成的具有隐甲烷结构的氧化锰八面体分子筛（OMS-2）首次用于氧化煤燃烧烟气中的气态元素汞（Hg ⁰）。Brunauer-Emmett-Teller（BET）表面积分析，X射线衍射（XRD），傅立叶变换红外（FT-IR）光谱，H _2程序升温还原（H ₂ -TPR）和X射线光电子能谱（XPS） ）测量用于表征催化剂。具有大表面积和丰富孔隙的OMS-2在100–250°C的宽温度范围内均具有出色的Hg ⁰氧化性能。在150°C的最佳工作温度下，93％Hg ⁰在高达每小时1,350,000 h ^-1的气体时空速下获得氧化效率。假设OMS-2催化剂上的Hg ⁰氧化遵循Mars-Maessen机理，其中气态Hg ⁰首先被吸附在OMS-2催化剂表面上，形成吸附的Hg ⁰，然后吸附的Hg ⁰被晶格氧化。氧气在催化剂表面上形成氧化汞（HgO）。烟道气中的HCl和NO都促进了Hg ^0的氧化，这主要是由于形成了诸如Cl ∗，NO _2之类的活性物质，它们与Hg ⁰反应形成了挥发性的汞物质。SO ₂抑制Hg ⁰通过将吸附的HgO还原为气态Hg ⁰或在催化剂表面生成硫酸盐来进行氧化。水蒸气在Hg ⁰氧化中也起抑制作用。但是，OMS-2催化剂的耐SO ₂和H ₂ O性能远远优于其他商用催化剂，这使其在工业上具有广阔的应用前景。该知识对于开发用于燃煤电厂的经济有效的Hg ⁰氧化催化剂是有益的。