Unveiling the Catalytic Merits of LaV3O9 over Conventional LaVO4 Polymorphs to Boost Desired Kinetics of Humid NOX Reduction and Poison Disintegration,ACS Catalysis

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Unveiling the Catalytic Merits of LaV3O9 over Conventional LaVO4 Polymorphs to Boost Desired Kinetics of Humid NOX Reduction and Poison Disintegration
ACS Catalysis ( IF 11.3 ) Pub Date : 2024-02-16 , DOI: 10.1021/acscatal.3c04828
Seokhyun Lee _{1,

2} , Jeongeun Choi ₁ , Heon Phil Ha ₁ , Jung-Hyun Lee ₂ , Jongwook Park ₃ , Jongsik Kim ₃

Affiliation

SO_Z^2– (Z = 3–4)-functionalized metal vanadates vary with the type of metal cations (Mⁿ⁺) for the Mⁿ⁺-O^2–-V⁵⁺ channels that fragment to impart Brönsted acidic bonds (BA^–-H⁺; SO_Z^2–-H⁺) and labile/mobile oxygens (O_L/O_M) with distinct populations and affinities for NO_X/O₂/H₂O/SO₂. SO_Z^2–-modified Mⁿ⁺-O^2–-V⁵⁺ fragments bind with NH₃ to activate Eley–Rideal (ER)-type selective catalytic NO_X reduction (SCR), yet, hardly enable O_L coordination with NO_X and are often hydrophilic, thereby limiting the activities of SCR or ammonium (bi)sulfate (AS/ABS) fragmentation, as gauged by the NO_X consumption (-r_NOX) and AS/ABS degradation rates (-r_AS/ABS), respectively. Here, we justified the use of nonreducible La³⁺-containing La³⁺-O^2–-V⁵⁺ channels, whose merits in accelerating SCR and AS/ABS fragmentation were found to be more pronounced for SO_Z^2–-modified LaV₃O₉ (LaV₃O₉-S) than for conventional/polymorphic LaVO₄ analogues (LaVO₄-S). Besides activating the ER-type SCR, LaV₃O₉-S bound with NO and activated Langmuir–Hinshelwood-type SCR, as opposed to LaVO₄-S. The pre-exponential factor (k′_APP,0) and -r_NOX were thus higher for LaV₃O₉-S than for LaVO₄-S and were coupled with the greater amount of O_M in the former, leading to superior SCR performance under wet gases. Moreover, compared to LaV₃O₉-S, its Sb₂O₅-promoted analogue (LaV₃O₉-Sb₂O₅-S) provided a larger number of NH₃-accessible BA^–-H⁺ bonds to achieve higher k′_APP,0/-r_NOX alongside higher O_M mobility. Furthermore, the LaV₃O₉-S and Sb₂O₅-S of LaV₃O₉-Sb₂O₅-S elevated the hydrophobicity and number of ABS-accessible BA^–-H⁺ bonds, respectively. LaV₃O₉-Sb₂O₅-S thus revealed a lower energy barrier and higher k′_APP,0 in AS/ABS pyrolysis than a commercial control (V₂O₅-WO₃-S), resulting in a higher -r_AS/ABS for the former. Consequently, LaV₃O₉-Sb₂O₅-S displayed superior SCR performance and greater hydrothermal resistance under SO₂-containing wet gases in comparison with V₂O₅-WO₃-S.

中文翻译：

揭示 LaV3O9 相对于传统 LaVO4 多晶型物的催化优点，以增强潮湿 NOX 还原和毒物分解的所需动力学

SO _Z^2– ( Z = 3–4)-功能化金属钒酸盐随 M ⁿ⁺ -O ^2– -V ^{5+通道的金属阳离子 (M}^{n +} )类型而变化，该通道断裂以赋予布朗斯台德酸性键 (BA ^– -H ⁺ ; SO _Z^2– -H ⁺ ) 和不稳定/移动氧 (O _L /O _M ) 具有不同的种群和对 NO _X /O ₂ /H ₂ O/SO ₂的亲和力。SO _Z^2–修饰的 Mn ⁺^-O 2– ^-V 5+^{片段与 NH}₃结合，激活 Eley–Rideal (ER) 型选择性催化 NO _X还原 (SCR)，但很难使 O _L与 NO 配位_X和通常是亲水性的，从而限制 SCR 或硫酸（氢）铵 (AS/ABS) 碎片的活性，如通过 NO _X消耗 (- r _NOX ) 和 AS/ABS 降解率 (- r _AS/ABS )来衡量，分别。在这里，我们证明了使用不可还原的La ³⁺包含La ³⁺ -O ^2– -V ^{5+通道，其在加速SCR 和AS/ABS 碎裂方面的优点被发现对于SO}_Z^2–修饰的LaV更为明显₃ O ₉ (LaV ₃ O ₉ -S) 优于传统/多晶型 LaVO ₄类似物 (LaVO ₄ -S)。除了激活 ER 型 SCR 之外，LaV ₃ O _{9 -S 还与 NO 结合并激活 Langmuir-Hinshelwood 型 SCR，这与 LaVO}₄ -S不同。_{因此，LaV 3} O ₉ -S的指前因子 ( k ' _APP,0 ) 和 -r NOX_高于LaVO 4 -S，并且与_前者中更多的 O _M相结合，从而产生优异的 SCR湿气体下的性能。此外，与LaV ₃ O ₉ -S相比，其Sb ₂ O ₅促进的类似物(LaV ₃ O ₉ -Sb ₂ O ₅ -S)提供了更多数量的NH ₃-可接近的 BA ^– -H ⁺键以实现更高的k ′ _APP,0 /- r _NOX以及更高的 O _M迁移率。此外，LaV ₃ O ₉ -Sb ₂ O ₅ -S的LaV ₃ O ₉ -S和Sb ₂ O ₅ -S分别提高了ABS可接近的BA ^- -H ⁺键的疏水性和数量。因此，与商业对照（V ₂ O ₅ -WO ₃ -S）相比， LaV ₃ O ₉ -Sb ₂ O ₅ -S 在 AS/ABS 热解中显示出更低的能垒和更高的k ' _APP,0，从而导致更高的 - r _AS/ABS为前者。因此，与V ₂ O ₅ -WO _{3 -S相比，LaV}₃ O ₉ -Sb ₂ O _{5 -S在含SO}₂湿气体下表现出优异的SCR性能和更大的耐水热性。

更新日期：2024-02-16

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