Abstract
It is a major challenge to develop the low–temperature catalysts (LTC, <250 °C) with excellent efficiency and stability for selective catalytic reduction (SCR) of NOx by NH3 from stationary sources. Mn-based LTC have been widely investigated due to its various valence states and excellent redox performance, while the poisoning by H2O or/and SO2 is one of the severe weaknesses. This paper reviews the latest research progress on Mn-based catalysts that are expected to break through the resistance, such as modified MnOx–CeO2, multi-metal oxides with special crystal or/and shape structures, modified TiO2 supporter, and novel carbon supporter (ACF, CNTs, GE), etc. The SCR mechanisms and promoting effects of redox cycle are described in detail. The reaction kinetics will be a benefit for the quantitative study of Eley–Rideal (ER) and Langmuir–Hinshelwood (LH) mechanisms. This paper also introduces the applications of quantum-chemical calculation using density functional theory to analyze the physic-chemical properties, explicates the reaction and poisoning mechanisms, and directs the design of functional catalysts on molecule levels. The intensive study of H2O/SO2 inhibition effects is by means of the combination analysis of in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and density functional theory (DFT), and the amplification of tolerance mechanisms will be helpful to design an excellent SCR catalyst.
Highlights
NOx is a generic term for mono-nitrogen oxides, namely NO and NO2, which are produced during combustion at high temperatures
The NH3 –selective catalytic reduction (SCR) technique has been widely used for the purification of NOx from industrial stationary sources due to its outstanding efficiency and strong stability, which can achieve over 90% NOx conversion [8]
We found that the MnOx /TiO2 –GE catalyst showed high NH3 –SCR activity and N2 selectivity, and good stability during low-temperature SCR at a high gas hourly space velocity (GHSV) of 67,000 h−1 [153]
Summary
According to BP’s Energy Outlook (2016), fossil fuels will continue to remain the dominant source of energy powering the world’s economy, supplying 60% of the energy increase out to 2035. Nitrates (PAN) can be formed from nitric oxide and contribute significantly to global photoIn addition, NOx species are harmful to the human body, which can diffuse through the alveolar oxidation pollution [1,2]. The NOx emissions are mainly from stationary source An overview of the historical development of NH3 –SCR technology and catalysts is available by Smirniotis et al [3] SCR of NOx using ammonia was patented in the United States by the Englehard. The V2 O5 –WO3 (MoO3 )/TiO2 catalyst has been widely applied in the industry due to the excellent NOx removal efficiency at a high temperature (300–400 ◦ C) [16,17]. It has become a hot topic to explore the development of the catalysts with excellent efficiency and strong stability that can be placed in low-temperature locations behind dust removal and desulfurizer units [4]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
