Gao Yu, Li Pingshang, Mei Wan
China Waterborne Transport Research Institute, Beijing 100083, China.
School of Environment, Beijing Jiaotong University, Beijing 100044, China.
Materials (Basel). 2025 Apr 14;18(8):1782. doi: 10.3390/ma18081782.
V/Pt/TiO tandem catalysts exhibit both an outstanding low-temperature NH conversion rate and high N selectivity in NH-SCO reactions, but the mechanism of high N selectivity remains unclear. In this work, V/Pt/TiO tandem catalysts were synthesized through a two-step impregnation-deposition method. The modulating effect of the V loading mount on NH-SCO performance was evaluated, and the relevant reaction mechanism was explored systematically. The results demonstrated that the synergistic effect of tandem NH oxidation and NH-SCR reactions could be regulated by changing the V loading amount, thereby modulating N selectivity. Compared with other V/Pt/TiO catalysts and previously reported SCO catalysts, the V/Pt/TiO catalyst with a V loading amount of 0.5 wt.% exhibited outstanding NH-SCO performance, which achieved complete NH conversion and >90% of N selectivity within a range of 250-450 °C. XPS, NH-TPD, and O-TPD results suggested that the increase in the V loading amount from 0.1 wt.% to 0.5 wt.% was conducive to increasing the relative contents of Pt and V species, as well as the amount of acid sites, oxygen species, and oxygen vacancies. Consequently, the synergistic effect of tandem NH oxidation and NH-SCR reactions was significantly enhanced, enabling the catalyst to exhibit excellent N selectivity. A further increase in the V loading amount from 0.5 wt.% to 0.9 wt.% would bring about the opposite effect to the above, resulting in a decline in catalytic performance. In situ DRIFTS results showed that a V loading amount of 0.5 wt.% was beneficial for -NH species to participate in NH-SCO reactions, thereby boosting N selectivity.
V/Pt/TiO 串联催化剂在 NH-SCO 反应中表现出出色的低温 NH 转化率和高 N 选择性，但高 N 选择性的机理尚不清楚。在这项工作中，通过两步浸渍-沉积法合成了 V/Pt/TiO 串联催化剂。评估了 V 负载量对 NH-SCO 性能的调节作用，并系统地探索了相关反应机理。结果表明，通过改变 V 负载量可以调节串联 NH 氧化和 NH-SCR 反应的协同效应，从而调节 N 选择性。与其他 V/Pt/TiO 催化剂和先前报道的 SCO 催化剂相比，V 负载量为 0.5 wt.% 的 V/Pt/TiO 催化剂表现出出色的 NH-SCO 性能，在 250-450 °C 范围内实现了 NH 的完全转化和 >90% 的 N 选择性。XPS、NH-TPD 和 O-TPD 结果表明，V 负载量从 0.1 wt.% 增加到 0.5 wt.% 有利于增加 Pt 和 V 物种的相对含量，以及酸位点、氧物种和氧空位的数量。因此，串联 NH 氧化和 NH-SCR 反应的协同效应显著增强，使催化剂表现出优异的 N 选择性。V 负载量从 0.5 wt.% 进一步增加到 0.9 wt.% 将产生与上述相反的效果，导致催化性能下降。原位 DRIFTS 结果表明，0.5 wt.% 的 V 负载量有利于 -NH 物种参与 NH-SCO 反应，从而提高 N 选择性。
