Isolated Pt Atoms Embedded in CuO Nanocatalysts for Selective Oxidation of Ammonia

Abstract

Establishing a binary synergy is promising to break the scaling relationship in heterogeneous catalysis. In this study, we created CuO nanocatalysts with isolated Pt atoms to selectively oxidize NH3 to N2, which helps to reduce fine particulate matter air pollution. These nanocatalysts had a reaction rate 30 times higher than CuO catalysts at 160 °C and 30% higher N2 selectivity than Pt catalysts at 99% NH3 conversion. Our experimental and theoretical findings showed that a reaction field separation strategy was responsible for the improved performance. Specifically, isolated Pt atoms facilitated the adsorption/activation of O2 while adjacent Cu atoms facilitated NH3 adsorption/activation. Through operando infrared spectroscopy and theoretical calculations, we found that the weaker adsorption of the NO2 intermediate on Cu sites was crucial for better performance. This research sets the foundation for developing high-performance heterogeneous catalysts.

Exploring the Impact of Palladium Species’ State on Catalytic Ammonia Elimination over Palladium Catalysts

“…Thus far, researchers have studied various materials for NH 3 oxidation, including noble metal catalysts (such as Pd, Pt, Ag, Ir, Ru, and Au), − transition metal oxide catalysts (like CuO, Fe 3 O 4 , Co 3 O 4 , NiO, and V 2 O 5 ), − and modified zeolite catalysts (such as ZSM-5, mordenite, Y, and beta). − Generally, noble metal catalysts show superior low-temperature activity while transition metal oxide catalysts and modified zeolite catalysts achieve higher N 2 selectivity. ,, Of these catalysts, the supported Pd catalyst is considered one of the most efficient AOC catalysts and is well known for its exceptional catalytic performance and high N 2 selectivity. ,,, …”

Unraveling the Mechanistic Origin of High N2 Selectivity in Ammonia Selective Catalytic Oxidation on CuO-Based Catalyst

“…Unfortunately, for those catalysts with high NH 3 conversions at low temperatures, appreciable amounts of N 2 O and NO are usually generated as byproducts. − N 2 O is a major greenhouse gas that has 300 times greater warming potential than CO 2 , and NO could contribute to the formation of acid rain and PM 2.5 , both of which can damage the atmospheric environment seriously. The contradiction between NH 3 oxidation activity and N 2 selectivity is the bottleneck of NH 3 –SCO. ,− …”

Research progress in ceria-based catalysts for the selective catalytic oxidation of NH<sub>3</sub>

“…考虑到治理成本, 降 解效率和实际工作条件, NH 3 催化燃烧(氧化)法被认 为是目前最合适的处理工厂固定源和机动车移动源 尾气氨逃逸的治理工艺. 因为在机动车尾气治理领域 中NH 3 催化氧化的目标产物一般是氮气和水, 因此催 化燃烧(氧化)法在机动车尾气治理领域中一般指的 是NH 3 选择性催化氧化法(Selective catalytic oxidation of NH 3 , NH 3 -SCO) [28,35] . .…”