Conventional and New Materials for Selective Catalytic Reduction (SCR) of NO_x

Abstract

It is important and necessary to minimize NOx pollutant released into the atmosphere owing to the harmful environmental and health effects brought by NOx emission. Many techniques are available to reduce NOx emission, among of them, Selective Catalytic Reduction (SCR) is considered as one of the most efficient techniques. Conventional SCR systems involve ammonia (NH3) or urea (CO(NH2)2) as a reducing reagent to reduce NOx to N2 and H2O at high temperatures 300–400 °C. Research on developing novel low‐temperature catalysts (LTC) for SCR of NOx still remains of interest. This work reviewed and compared conventional SCR catalysts with newly emerging Metal‐Organic‐Frame (MOFs) materials as potential alternatives for SCR catalysts.

WO3–V2O5 Active Oxides for NOx SCR by NH3: Preparation Methods, Catalysts’ Composition, and Deactivation Mechanism—A Review

“…Agriculture, industries, power generation plants, and transportation are the major sources responsible of air pollution [1]: Ozone depletion, eutrophication, smog, global warming, and acid rain have attracted wide attention from human beings [2,3]. In order to reduce air pollution, new regulations have been introduced in the latest years, such as the Directive 2010/75/EU of the European Parliament and of the Council concerning industrial activities, European standards for vehicles' exhaust gas emissions in Europe, as well as EPA (Environmental Protection Agency) tier regulations in the USA and analogous emission standards developed by the Japanese government.…”

“…Many techniques have been applied for the abatement of NO x emissions, such as pre-combustion and combustion modifications [6,7], as well tail-end control equipment [2,8]. Tail-end control devices are the most efficient in the removal of NO x , including selective noncatalytic reduction (SNCR) [9,10], selective catalytic reduction (SCR) [11], NO x storage/reduction (NSR) [12], and electron beam radiation [2]. Among the above-mentioned methods, NOx-SCR, which was firstly developed in Japan in the 1970s, is applied worldwide today, being regarded as a promising technology [13].…”

Spatially Nanoconfined Architectures: A Promising Design for Selective Catalytic Reduction of NOx

“…Therefore, enormous researches continue to develop NH 3 −SCR catalysts with the aim to improve the catalytic performance [6] . Many excellent reviews have been published in this field, focusing on the catalysts, mechanisms, and practical application for NH 3 −SCR [3,4b,7] . However, the strategies of structural modifications for NH 3 −SCR catalysts are rarely discussed.…”

Effect of Ordered Mesoporous Alumina Support on the Structural and Catalytic Properties of Mn−Ni/OMA Catalyst for NH3−SCR Performance at Low‐temperature

“…NO x exhausted from the consumption of fossil fuel, including the stationary source and mobile source, maintain a principle source of air pollution. They would not only bring about a great deal of environmental issues for instance the depletion of ozonosphere, acid rain, photochemical smoke, and fine particle contamination but also pose threat to human health . NH 3 −SCR of NO x is identified as one of the most effective technique to alleviate NO x emitted from stationary emission to meet the ever‐tightening emission standard …”