Synergistic promotion of transition metal ion-exchange in TiO 2 nanoarray-based monolithic catalysts for the selective catalytic reduction of NO x with NH 3
Synergistic promotion of transition metal ion-exchange in TiO 2 nanoarray-based monolithic catalysts for the selective catalytic reduction of NO x with NH 3
复制标题
TiO 2 纳米阵列基整体催化剂中过渡金属离子交换的协同促进用于NH 3 选择性催化还原NO x
DOI：
10.1039/d2cy00996j
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发表时间：
2022
影响因子：
5
通讯作者：
Gao, Pu-Xian
中科院分区：
文献类型：
--
作者：
Lu, Xingxu;Dang, Yanliu;Li, Meilin;Zhu, Chunxiang;Liu, Fangyuan;Tang, Wenxiang;Weng, Junfei;Ruan, Mingyue;Suib, Steven L.;Gao, Pu-Xian
二氧化钛负载催化剂在氮氧化物选择性催化还原(SCR)中得到了广泛的研究，但对多组分SCR催化剂中的协同作用还缺乏全面的了解。本论文以质子化的钛酸盐为前驱体，通过离子交换将过渡金属元素(V、Cr、Mn、Fe、Co、Ni、Cu、La、Ce)负载到纳米二氧化钛阵列上。在这些催化剂中，掺锰催化剂具有较好的NO转化率和氮气选择性。铜的共掺杂改善了催化剂的还原性能，增加了表面Mn4+物种和化学吸附的活性氧，提高了NH3和NOx物种的吸附能力，从而提高了催化剂的低温活性。虽然Ce与Mn共掺杂抑制了NH3和NOx衍生物种的表面吸附和生成，但它提高了高温下的氮气选择性。在锰基催化剂中加入铜和Ce作为掺杂元素，既提高了催化剂的低温活性，又提高了高温氮气的选择性，并且由于能垒较低，证明了三金属催化剂中以朗缪尔-辛谢伍德反应为主的反应机理。
TiO2 supported catalysts have been widely studied for the selective catalytic reduction (SCR) of NOx; however, comprehensive understanding of synergistic interactions in multi-component SCR catalysts is still lacking. Herein, transition metal elements (V, Cr, Mn, Fe, Co, Ni, Cu, La, and Ce) were loaded onto TiO2 nanoarrays via ion-exchange using protonated titanate precursors. Amongst these catalysts, Mn-doped catalysts outperform the others with satisfactory NO conversion and N2 selectivity. Cu co-doping into the Mn-based catalysts promotes their low-temperature activity by improving reducibility, enhancing surface Mn4+ species and chemisorbed labile oxygen, and elevating the adsorption capacity of NH3 and NOx species. While Ce co-doping with Mn prohibits the surface adsorption and formation of NH3 and NOx derived species, it boosts the N2 selectivity at high temperatures. By combining Cu and Ce as doping elements in the Mn-based catalysts, both the low-temperature activity and the high-temperature N2 selectivity are enhanced, and the Langmuir–Hinshelwood reaction mechanism was proved to dominate in the trimetallic Cu–Ce–5Mn/TiO2 catalysts due to the low energy barrier.