Micro-physicochemical characteristics and low-temperature SCR activities of the Mn–Ce–Cr catalysts on different carriers were investigated with SEM, XRD, XPS, FTIR, and denitration experiments. Mn–Ce–Cr catalysts carried on TiO₂ and ZrO₂, and composite carrier containing Al₂O₃ and TiO₂ had visible element interactions on the surfaces, and Mn presented the mixed valences of Mn³⁺ and Mn⁴⁺. Mn³⁺ was transferred to Mn⁴⁺ due to the oxidation processes of Ce³⁺ to Ce⁴⁺ and Cr³⁺ to Cr⁶⁺, and the O_α/O_β ratio decreased during the SCR process. Compared with single carriers such as TiO₂ or ZrO₂, the catalysts on the composite carriers of Al₂O₃ and TiO₂ had better pore structures and higher fractions of Mn⁴⁺, Ce³⁺, Cr⁶⁺, and chemisorbed oxygen. It could also absorb the coordination-state NH₃ well, especially the higher activity l-acid sites during the SCR process, and contribute to the formation of composite oxide Mn_xTi_1−xO on Mn–Ce–Cr/Al₂O₃+TiO₂ catalyst. All the above factors had positive effects on the low-temperature SCR. However, Co-doping in Mn–Ce–Cr catalysts could not improve the pore structures or promote the dispersions of Mn–Ce–Cr active substances on the carrier surface. Groups such as nitrates and nitrites produced by NO adsorption would hinder the adsorption of NH₃ and low-temperature SCR. Mn–Ce–Cr/Al₂O₃+TiO₂ catalyst had high low-temperature SCR activity, while Mn–Ce–Cr/ZrO₂ catalyst was the most unstable with the lowest denitration efficiency. Moreover, for the scrapped catalyst from coal-fired power plants, it could still be used as the carrier of the Mn–Ce–Cr catalyst, and its SCR characteristics were much better than the above catalysts, especially at broader temperature range.

中文翻译：

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不同载体的锰基催化剂的低温SCR脱硝机理研究

通过SEM，XRD，XPS，FTIR和脱硝实验研究了Mn-Ce-Cr催化剂在不同载体上的微理化特性和低温SCR活性。Mn-Ce-Cr催化剂负载在TiO ₂和ZrO _2上，并且含有Al ₂ O ₃和TiO _2的复合载体在表面上具有可见的元素相互作用，并且Mn呈现Mn ³⁺和Mn ⁴⁺的混合价。的Mn ³⁺被转移到的Mn ⁴⁺由于Ce的氧化过程³⁺至Ce的⁴⁺和Cr ³⁺为Cr ⁶⁺，和O _α/ _Oβ比在SCR过程中降低。与单一载体如TiO ₂或ZrO _2相比，在Al ₂ O ₃和TiO ₂复合载体上的催化剂具有更好的孔结构和更高的Mn ⁴⁺，Ce ³⁺，Cr ⁶⁺和化学吸附氧分数。它也可以吸收该协调状态NH ₃好，尤其是在较高的活性升期间SCR过程-酸位点，并有利于复合氧化物的形成的Mn _X的Ti _{1 -x} O于锰铈的Cr / Al的₂ ö ₃+ TiO ₂催化剂。以上所有因素对低温SCR都有积极影响。但是，Mn-Ce-Cr催化剂中的共掺杂不能改善孔结构或促进Mn-Ce-Cr活性物质在载体表面的分散。NO吸附产生的硝酸盐和亚硝酸盐等基团会阻碍NH ₃和低温SCR的吸附。Mn–Ce–Cr / Al ₂ O ₃ + TiO ₂催化剂具有较高的低温SCR活性，而Mn–Ce–Cr / ZrO ₂催化剂最不稳定，脱硝效率最低。此外，对于燃煤电厂报废的催化剂，它仍然可以用作Mn–Ce–Cr催化剂的载体，其SCR特性比上述催化剂要好得多，尤其是在较宽的温度范围内。