揭示钒酸镍相高耐水性的重要性，以改善催化 NOX 还原和毒物热解的动力学参数或结果,Journal of Materials Chemistry A

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揭示钒酸镍相高耐水性的重要性，以改善催化 NOX 还原和毒物热解的动力学参数或结果
Journal of Materials Chemistry A ( IF 10.7 ) Pub Date : 2023-05-09 , DOI: 10.1039/d3ta01977b
Seokhyun Lee _{1,

2} , Heon Phil Ha ₁ , Jung-Hyun Lee ₂ , Jongsik Kim ₃

Affiliation

人为烟气由NO _X /SO ₂ /H ₂ O组成，其中H _{2 O阻力在激活NH}₃辅助催化NO _X还原（SCR）的酸性/氧化还原循环时经常被低估，SO ₂ /H ₂ O - 硫酸氢铵 (AS/ABS) 毒物或 AS/ABS 热解的诱导演化。在此，TiO ₂负载的钒酸镍 (Ni _X V ₂ O _{X +5} ; X = 1–3) 用 SO _Z²⁻ ( Z = 3–4) 功能化以模拟生成的 Ni _X含 SO ₂的湿烟气下的 –S 表面，单/双齿 SO _Z²⁻改性剂通过质子化作用转化为布朗斯台德酸性键 (B ⁻ –H ⁺ ) 。Ni ₁ –S 在循环酸循环中表现出最高的效率，这在 Ni _X –S 催化剂中其最高的 NO _X消耗率 (− r _NO_{_{X ) 证明了这一点。}}这是通过对 B ⁻ –NH ₄⁺ ⋯O _L⁻ –M ⁽ⁿ⁻¹⁾⁺的最小 H _{2 O 结合亲和力实现的}中间体参与 SCR 的速率决定步骤，从而揭示 Ni ₁ –S 上 SCR 所需的最小能垒。此外，Ni _{1 –S 在 Ni}_X –S 催化剂中提供了最大量的不稳定氧和最高的氧迁移率，从而在循环氧化还原循环中实现了最高效率。值得注意的是，Ni ₁ –S 表面在包含促进剂 Sb ₂ O ₅后显着排斥 H ₂ O ，同时提高了所得 Ni ₁ –Sb–S 的氧化还原循环效率。因此，除了表现出比 Ni _X更大的 − r _NO_{_{X值或 SCR 结果之外}}–S 和商业催化剂 (V ₂ O ₅ –WO ₃ –S) 在低温下，Ni _{1 –Sb–S 还减少了通过逃避 H}₂ O 吸附而积累的 AS/ABS 的数量。H ₂ O 阻力对于加速 B ⁻ –H ₂ O⋯SO ₂ ⋯H ₂ O 在 Ni ₁ –Sb–S 表面的解离也是至关重要的。_{因此，与 V 2} O ₅ –WO ₃ –S 相比， Ni ₁ –Sb–S 揭示了更高的 AS/ABS 降解率和更小的 AS/ABS 热解所需的能垒。重要的是，Ni ₁–Sb–S 显着增强了Sb-上 V ₂ O ₅ –WO ₃ –S 和 SO _Z²⁻修饰的 Mn ₁ V ₂ O ₆（或 Cu ₃ V ₂ O ₈ ）对 AS/ABS 或水热老化的抵抗力促进了我们小组先前报道的TiO _{2 。}

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Unlocking the significance of high H2O resistance for nickel vanadate phases to improve the kinetic parameters or consequences of catalytic NOX reduction and poison pyrolysis

Anthropogenic flue gases consist of NO_X/SO₂/H₂O, among which H₂O resistance is often underrated in activating the acidic/redox cycles of NH₃-assisted catalytic NO_X reduction (SCR), SO₂/H₂O-induced evolution of ammonium (bi)sulfate (AS/ABS) poisons, or AS/ABS pyrolysis. Herein, TiO₂-supported nickel vanadates (Ni_XV₂O_X+5; X = 1–3) were functionalized with SO_Z²⁻ (Z = 3–4) to simulate the resulting Ni_X–S surfaces under a SO₂-containing wet flue gas, at which mono/bidentate SO_Z²⁻ modifiers transform into Brønsted acidic bonds (B⁻–H⁺) via protonation. Ni₁–S exhibited the highest efficiency in the recurring acidic cycle, as proved by its highest NO_X consumption rate (−r_{NO_X}) among Ni_X–S catalysts. This was enabled by the smallest H₂O binding affinity to the B⁻–NH₄⁺⋯O_L⁻–M⁽ⁿ⁻¹⁾⁺ intermediates involved in the rate-determining step of the SCR, thus revealing the smallest energy barrier needed for SCR on Ni₁–S. Moreover, Ni₁–S provided the largest quantity of labile oxygens and the highest oxygen mobility among Ni_X–S catalysts, leading to the highest efficiency in the recurring redox cycle. Notably, the Ni₁–S surface repelled H₂O markedly upon the inclusion of promotive Sb₂O₅ alongwith the improvement of redox cycling efficiency for the resulting Ni₁–Sb–S. Hence, aside from exhibiting greater −r_{NO_X} values or SCR consequences than Ni_X–S and a commercial catalyst (V₂O₅–WO₃–S) at low temperatures, Ni₁–Sb–S also reduced the number of AS/ABS accumulated by evading H₂O adsorption. H₂O resistance was also crucial to accelerate desorptive B⁻–H₂O⋯SO₂⋯H₂O dissociation on the Ni₁–Sb–S surface. Ni₁–Sb–S thus unveiled a higher AS/ABS degradation rate and a smaller energy barrier required for AS/ABS pyrolysis than V₂O₅–WO₃–S. Importantly, Ni₁–Sb–S significantly enhanced the resistance toward AS/ABS or hydrothermal aging over V₂O₅–WO₃–S and SO_Z²⁻-modified Mn₁V₂O₆ (or Cu₃V₂O₈) on Sb-promoted TiO₂ reported previously by our group.

更新日期：2023-05-09

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