Effect of Catalyst Crystallinity on V-Based Selective Catalytic Reduction with Ammonia

Lee, Min Seong; Kim, Sun-I; Lee, Myeung-jin; Ye, Bora; Kim, Taehyo; Kim, Hong-Dae; Lee, Jung Woo; Lee, Jun Young

doi:10.3390/nano11061452

Cited by 8 publications

(7 citation statements)

References 41 publications

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“…Vanadium is mainly present in the form of + 4 or + 5 oxide states, but the rate at which side reactions such as SO 2 oxidation and N 2 O generation occur and the low-temperature catalytic efficiency change, depend on the ratio of oxidation states present [ 73 ]. Therefore, studies on pH control in an aqueous vanadium precursor solution, changing the calcination temperature and maintenance time, and using various precursors are of great interest [ 54 , 74 , 75 ]. Previous studies have shown that the vanadium-oxalate complex undergoes thermal decomposition to V 2 O 5 in the presence of + 4 and + 5 compounds at approximately 270 °C.…”

Section: Vanadium-based Scr Catalystsmentioning

confidence: 99%

Recent trends in vanadium-based SCR catalysts for NOx reduction in industrial applications: stationary sources

Jeong

Lee

et al. 2022

Nano Convergence

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Vanadium-based catalysts have been used for several decades in ammonia-based selective catalytic reduction (NH3-SCR) processes for reducing NOx emissions from various stationary sources (power plants, chemical plants, incinerators, steel mills, etc.) and mobile sources (large ships, automobiles, etc.). Vanadium-based catalysts containing various vanadium species have a high NOx reduction efficiency at temperatures of 350–400 °C, even if the vanadium species are added in small amounts. However, the strengthening of NOx emission regulations has necessitated the development of catalysts with higher NOx reduction efficiencies. Furthermore, there are several different requirements for the catalysts depending on the target industry and application. In general, the composition of SCR catalyst is determined by the components of the fuel and flue gas for a particular application. It is necessary to optimize the catalyst with regard to the reaction temperature, thermal and chemical durability, shape, and other relevant factors. This review comprehensively analyzes the properties that are required for SCR catalysts in different industries and the development strategies of high-performance and low-temperature vanadium-based catalysts. To analyze the recent research trends, the catalysts employed in power plants, incinerators, as well as cement and steel industries, that emit the highest amount of nitrogen oxides, are presented in detail along with their limitations. The recent developments in catalyst composition, structure, dispersion, and side reaction suppression technology to develop a high-efficiency catalyst are also summarized. As the composition of the vanadium-based catalyst depends mostly on the usage in stationary sources, various promoters and supports that improve the catalyst activity and suppress side reactions, along with the studies on the oxidation state of vanadium, are presented. Furthermore, the research trends related to the nano-dispersion of catalytically active materials using various supports, and controlling the side reactions using the structure of shaped catalysts are summarized. The review concludes with a discussion of the development direction and future prospects for high-efficiency SCR catalysts in different industrial fields.

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Section: Vanadium-based Scr Catalystsmentioning

confidence: 99%

Recent trends in vanadium-based SCR catalysts for NOx reduction in industrial applications: stationary sources

Jeong

Lee

et al. 2022

Nano Convergence

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“…Thus, many nations and governments have strengthened their emission regulation policies to control nitrogen oxide emissions . Several processes have been proposed to either eliminate or control nitrogen oxide emissions: for example, selective catalytic reduction (SCR), selective noncatalytic reduction, and non-selective catalytic reduction. − Among these technologies, SCR is the most advanced and efficient; it works by converting NO X in exhaust gas into N 2 and H 2 O, using ammonia (NH 3 ) as a reducing agent. − This technology can reduce up to 60–90% of NO X in exhaust gas, contain secondary pollutant emission, and can operate at a relatively low temperature (∼350 °C) . Many transition-metal catalysts have been used for SCR reactions, such as vanadium, tungsten, copper, iron, and manganese oxides.…”

Section: Introductionmentioning

confidence: 99%

Nitration-Promoted Vanadate Catalysts for Low-Temperature Selective Catalytic Reduction of NO_X with NH₃

Kim,

Choi,

Lee

et al. 2023

ACS Omega

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Vanadium-based catalysts have been commercially used in selective catalytic reduction (SCR), owing to their high catalytic activity and effectiveness across a wide temperature range; however, their catalytic efficiency decreases at lower temperatures under exposure to SO X . This decrease is largely due to ammonium sulfate generation on the catalyst surface. To overcome this limitation, we added ammonium nitrate to the V2O5-WO3/TiO2 catalyst, producing a V2O5-WO3/TiO2 catalyst with nitrate functional groups. With this approach, we found that it was possible to adjust the amount of these functional groups by varying the amount of ammonium nitrate. Overall, the resultant nitrate V2O5-WO3/TiO2 catalyst has large quantities of NO3 – and chemisorbed oxygen, which improves the density of Brønsted and Lewis acid sites on the catalyst surface. Furthermore, the nitrated V2O5-WO3/TiO2 catalyst has a high NO X removal efficiency and N2 selectivity at low temperatures (i.e., 300 °C); this is because NO3 – and chemisorbed oxygen, generated by nitrate treatment, facilitated the occurrence of a fast SCR reaction. The approach outlined in this study can be applied to a wide range of SCR catalysts, allowing for the development of more, low-temperature SCR catalysts.

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“…NO X is a compound of nitrogen and oxygen, including NO, NO 2 , N 2 O, and N 2 O 3 ; it can result in ozone layer depletion, greenhouse effect, photochemical smog, and acid rain. Accordingly, various environmental protection regulations have been strengthened, and NO X emission standards have become more stringent [2,3]. Generally, most NO X emissions originate from combustion in stationary, such as coal-fired power plants [4,5].…”

Section: Introductionmentioning

confidence: 99%

High-Dispersed V2O5-CuOX Nanoparticles on h-BN in NH3-SCR and NH3-SCO Performance

Lee

Kim

et al. 2022

Nanomaterials

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Typically, to meet emission regulations, the selective catalytic reduction of NOX with NH3 (NH3-SCR) technology cause NH3 emissions owing to high NH3/NOX ratios to meet emission regulations. In this study, V-Cu/BN-Ti was used to remove residual NOX and NH3. Catalysts were evaluated for selective catalytic oxidation of NH3 (NH3-SCO) in the NH3-SCR reaction at 200–300 °C. The addition of vanadium and copper increased the number of Brønsted and Lewis acid sites available for the reaction by increasing the ratio of V5+ and forming Cu+ species, respectively. Furthermore, h-BN was dispersed in the catalyst to improve the content of vanadium and copper species on the surface. NH3 and NOX conversion were 98% and 91% at 260 °C, respectively. Consequently, slipped NH3 (NH3-Slip) emitted only 2% of the injected ammonia. Under SO2 conditions, based on the NH3 oxidation reaction, catalytic deactivation was improved by addition of h-BN. This study suggests that h-BN is a potential catalyst that can help remove residual NOX and meet NH3 emission regulations when placed at the bottom of the SCR catalyst layer in coal-fired power plants.

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Effect of Catalyst Crystallinity on V-Based Selective Catalytic Reduction with Ammonia

Cited by 8 publications

References 41 publications

Recent trends in vanadium-based SCR catalysts for NOx reduction in industrial applications: stationary sources

Recent trends in vanadium-based SCR catalysts for NOx reduction in industrial applications: stationary sources

Nitration-Promoted Vanadate Catalysts for Low-Temperature Selective Catalytic Reduction of NO_X with NH₃

High-Dispersed V2O5-CuOX Nanoparticles on h-BN in NH3-SCR and NH3-SCO Performance

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Effect of Catalyst Crystallinity on V-Based Selective Catalytic Reduction with Ammonia

Cited by 8 publications

References 41 publications

Recent trends in vanadium-based SCR catalysts for NOx reduction in industrial applications: stationary sources

Recent trends in vanadium-based SCR catalysts for NOx reduction in industrial applications: stationary sources

Nitration-Promoted Vanadate Catalysts for Low-Temperature Selective Catalytic Reduction of NOX with NH3

High-Dispersed V2O5-CuOX Nanoparticles on h-BN in NH3-SCR and NH3-SCO Performance

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Product

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About

Nitration-Promoted Vanadate Catalysts for Low-Temperature Selective Catalytic Reduction of NO_X with NH₃