Promotional Effect of Manganese on Selective Catalytic Reduction of NO by CO in the Presence of Excess O2 over M@La–Fe/AC (M = Mn, Ce) Catalyst

Abstract

The catalytic performance of a series of La-Fe/AC catalysts was studied for the selective catalytic reduction (SCR) of NO by CO. With the increase in La content, the Fe2+/Fe3+ ratio and amount of surface oxygen vacancies (SOV) in the catalysts increased; thus the catalytic activity improved. Incorporating the promoters to La3-Fe1/active carbon (AC) catalyst could affect the catalyst activity by changing the electronic structure. The increase in Fe2+/Fe3+ ratio after the promoter addition is possibly due to the extra synergistic interaction of M (Mn and Ce) and Fe through the redox equilibrium of M3+ + Fe3+ ↔ M4+ + Fe2+. This phenomenon could have improved the redox cycle, enhanced the SOV formation, facilitated NO decomposition, and accelerated the CO-SCR process. The presence of O2 enhanced the formation of the C(O) complex and improved the activation of the metal site. Mn@La3-Fe1/AC catalyst revealed an excellent NO conversion of 93.8% at 400 °C in the presence of 10% oxygen. The high catalytic performance of MnOx and double exchange behavior of Mn3+ and Mn4+ can increase the number of SOV and improve the catalytic redox properties.

Carbon dioxide enrichment in a decarbonised future

“…There are two main approaches to removing NO x : ad/absorption, or destruction of NO x by transforming it into benign compounds (Gholami, Tomas, Gholami, & Vakili, 2020).…”

“…Selective catalytic reduction (SCR) is the most common approach to removing NO x (Gholami et al 2020). There are multiple variants, of which the most commonly-used in greenhouse horticulture is urea injection, for cleaning CHP flue gases on site (Vermeulen & van der Lans, 2011).…”

Shear Stress on the Structure Control of a Supported Fly Ash‐Based Catalyst and Its Application in SCR* Denitration

“…However, the common problems of these two methods are uneven loading of active components, non-compliance with the calculation standard, long impregnation and roasting time, and complicated process. [32] The classical shear model theory studies the nucleation process of catalysts from the perspective of thermodynamic instability. The experiments show that the critical bubble core grows into a stable bubble through thermodynamic diffusion, and the shear effect of flow field also promotes the transition from the critical bubble core to a stable bubble.…”

“…methods can embed the active components into the carrier in different forms, thus generating catalytic effect. However, the common problems of these two methods are uneven loading of active components, non‐compliance with the calculation standard, long impregnation and roasting time, and complicated process [32] …”

Photodegradation of Methylene Blue and Evans Blue by Iron and Sulphur Doped TiO2 Nanophotocatalyst under Ultraviolet and Visible Light Irradiation

“…Various fabrication methods have been performed to synthesis TiO2 NPs such as sol-gel [28,29], microemuolsion, reverse micells [30][31][32][33], Co-precipitation [34,35], pyrolysis [36,37], laser ablation [38,39], chemical vapor deposition [40,41], physical vapor deposition [42,43], solvo-thermal [44,45], electrochemical deposition [46,47], mechano-chemical [48,49], combustion [50,51], sono-chemical microwave [52,53] and hydrothermal [54,55]. Among of them, the hydrothermal method possesses more benefits such as cheap cost, controllable in synthesis, productive, no needing thermal operation and low pollutions [56][57][58].…”