Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control, National Engineering Laboratory for VOCs Pollution Control Technology and Equipment, School of Environment and Energy, South China University of Technology, 510006 Guangzhou, China.
Laboratory of Industrial Chemistry, Ruhr-University Bochum, Universitätsstr. 150, Bochum 44780, Germany.
Environ Sci Technol. 2022 Oct 4;56(19):14008-14018. doi: 10.1021/acs.est.2c03666. Epub 2022 Sep 13.
Selective catalytic ammonia-to-dinitrogen oxidation (NH-SCO) is highly promising for the abatement of NH emissions from flue gas purification devices. However, there is still a lack of high-performance and cost-effective NH-SCO catalysts for real applications. Here, highly dispersed, electron-deficient Cu-based catalysts were fabricated using nitrogen-doped carbon nanotubes (NCNT) as support. In NH-SCO catalysis, the Cu/NCNT outperformed Cu supported on N-free CNTs (Cu/OCNT) and on other types of supports ( activated carbon, AlO, and zeolite) in terms of activity, selectivity to the desired product N, and HO resistance. Besides, Cu/NCNT demonstrated a better structural stability against oxidation and a higher NH storage capacity (in the presence of HO vapor) than Cu/OCNT. X-ray photoelectron spectroscopy revealed that the surface N species facilitated electron transfer from Cu to the NCNT support, resulting in electron-deficient Cu catalysts with superior redox properties, which are essential for NH-SCO catalysis. By temperature-programmed surface reaction studies and systematic kinetic measurements, we unveiled that the NH-SCO reaction over Cu/NCNT proceeded via the internal selective catalytic reaction (-SCR) route; , NH was oxidized first to NO, which then reacted with NH and O to form N and HO. This study paves a new route for the design of highly active, HO-tolerant, and low-cost Cu catalysts for the abatement of slip NH from stationary emissions via selective oxidation to N.
选择性催化氨到氮气氧化（NH-SCO）对于从烟气净化装置中去除 NH 排放非常有前景。然而，对于实际应用，仍然缺乏高性能和具有成本效益的 NH-SCO 催化剂。在这里，使用氮掺杂碳纳米管（NCNT）作为载体制备了高度分散的电子缺Cu 基催化剂。在 NH-SCO 催化中，Cu/NCNT 在活性、所需产物 N 的选择性和耐 HO 方面优于在无 N 的 CNT（Cu/OCNT）和其他类型的载体（活性炭、AlO 和沸石）上负载的 Cu。此外，Cu/NCNT 表现出比 Cu/OCNT 更好的氧化结构稳定性和更高的 NH 存储能力（在 HO 蒸汽存在下）。X 射线光电子能谱表明，表面 N 物种促进了 Cu 向 NCNT 载体的电子转移，导致具有优越氧化还原性能的电子缺 Cu 催化剂，这对于 NH-SCO 催化至关重要。通过程序升温表面反应研究和系统动力学测量，我们揭示了 Cu/NCNT 上的 NH-SCO 反应通过内部选择性催化反应（-SCR）途径进行；也就是说，NH 首先被氧化为 NO，然后与 NH 和 O 反应形成 N 和 HO。这项研究为通过选择性氧化去除固定源排放中的泄漏 NH 设计高活性、耐 HO 和低成本的 Cu 催化剂开辟了一条新途径。
