• Title/Summary/Keyword: Noble metal-free catalyst

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Study of the Optimal Calcination Temperature of an Al/Co/Ni Mixed Metal Oxide as a DeNOx Catalyst for LNT

  • Jang, Kil Nam;Han, Kwang Seon;Hong, Ji Sook;You, Young-Woo;Suh, Jeong Kwon;Hwang, Taek Sung
    • Clean Technology
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    • v.21 no.3
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    • pp.184-190
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    • 2015
  • Most of LNT catalysts use noble metals such as Pt for low temperature NOx oxidation but there is an economic weakness. For the purpose of overcoming this, this study is to develop DeNOx catalyst for LNT excluding PGM (platinum group metal) such as Pt, Pd, Rh, etc. To do so, Al/Co/Ni catalyst selected as a preliminary test is used to study fundamental property and NOx’s conversion according to calcined temperature. Ultimately, that is, Al/Co/Ni mixed metal oxide which does not use PGM is selected and physicochemical characterization is performed by way of XRD, EDS, SEM, BET and ramp test and NOx conversion is also analyzed. This study shows that all samples consist of mixed oxides of spinel structure of Co2AlO4 and NiAl2O4 and have enough pore volume and size for redox. But as a result of NH3-TPD test, it is desired that calcined temperature needs to be maintained at 700 ℃ or lower. Also only samples which are processed under 500 ℃ satisfied NO and NOx conversion simultaneously through ramp test. Based on this study’s results, optimum calcined temperature for Al/Co/Ni=1.0/2.5/0.3 mixed metal oxide catalyst is 500 ℃.

A study on γ-Al2O3 Catalyst for N2O Decomposition (N2O 분해를 위한 γ-Al2O3 촉매에 관한 연구)

  • Eun-Han Lee;Tae-Woo Kim;Segi Byun;Doo-Won Seo;Hyo-Jung Hwang;Jueun Baek;Eui-Soon Jeong;Hansung Kim;Shin-Kun Ryi
    • Clean Technology
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    • v.29 no.2
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    • pp.126-134
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    • 2023
  • Direct catalytic decomposition is a promising method for controlling the emission of nitrous oxide (N2O) from the semiconductor and display industries. In this study, a γ-Al2O3 catalyst was developed to reduce N2O emissions by a catalytic decomposition reaction. The γ-Al2O3 catalyst was prepared by an extrusion method using boehmite powder, and a N2O decomposition test was performed using a catalyst reactor that was approximately 25.4 mm (1 in) in diameter packed with approximately 5 mm of catalysts. The N2O decomposition tests were carried out with approximately 1% N2O at 550 to 750 ℃, an ambient pressure, and a GHSV=1800-2000 h-1. To confirm the N2O decomposition properties and the effect of O2 and steam on the N2O decomposition, nitrogen, air, and air and steam were used as atmospheric gases. The catalytic decomposition tests showed that the 1% N2O had almost completely disappeared at 700 ℃ in an N2 atmosphere. However, air and steam decreased the conversion rate drastically. The long term stability test carried out under an N2 atmosphere at 700 ℃ for 350 h showed that the N2O conversion rate remained very stable, confirming no catalytic activity changes. From the results of the N2O decomposition tests and long-term stability test, it is expected that the prepared γ-Al2O3 catalyst can be used to reduce N2O emissions from several industries including the semiconductor, display, and nitric acid manufacturing industry.