Clean Technology (청정기술)

The Korean Society of Clean Technology (한국청정기술학회)
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A Study on the Characteristics of CO Oxidation by NO Poisoning in Pt/TiO2 Catalyst

Pt/TiO2 촉매에서의 NO 피독에 의한 CO 산화반응특성 연구

  • Kim, Min Su (Department of Environmental Energy Engineering, Graduate school of Kyonggi University) ;
  • Kim, Se Won (Thermochemical Energy System Group, Korea Institute of Industrial Technology) ;
  • Hong, Sung Chang (Department of Environmental Energy Engineering, Kyonggi University)
  • 김민수 (경기대학교 일반대학원 환경에너지공학과) ;
  • 김세원 (한국생산기술연구원 고온에너지시스템그룹) ;
  • 홍성창 (경기대학교 환경에너지공학과)
  • Received : 2019.08.30
  • Accepted : 2019.09.17
  • Published : 2019.12.31
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Abstract

This study was conducted to investigate the characteristics of CO oxidation by NO poisoning in Pt/TiO2 catalyst prepared by wet impregnation method and calcined at 400 ℃. In order to confirm the NO poisoning effect of the Pt/TiO2 catalyst, the change of reaction activity was observed when NO was injected during the CO+O2 reaction where it was ascertained that the CO conversion rate rapidly decreased below 200 ℃. Also, CO conversion was not observed below 125 ℃. Recovery of initial CO conversion was not verified even if NO injection was blocked at 125 ℃. Accordingly, various analyses were performed according to NO injection. First, as a result of the TPD analysis, it was confirmed that NO pre-adsorption in catalyst inhibited CO adsorption and conversion desorption from adsorbed CO to CO2. When NO was pre-adsorbed, it was confirmed through H2-TPR analysis that the oxygen mobility of the catalyst was reduced. In addition, it was validated through FT-IR analysis that the redox cycle (Pt2+→Pt0→Pt2+) of the catalyst was inhibited. Therefore, the presence of NO in the Pt/TiO2 catalyst was considered to be a poisoning factor in the CO oxidation reaction, and it was determined that the oxygen mobility of the catalyst is required to prevent NO poisoning.

본 연구는 습윤함침법으로 제조하여 400 ℃에서 소성한 Pt/TiO2 촉매를 이용하여 NO 피독에 의한 CO 산화반응특성에 대하여 확인하였다. Pt/TiO2 촉매의 NO 피독영향을 확인하기 위하여 CO + O2 반응 중 NO를 주입하면서 반응활성의 변화를 관찰하였으며, 200 ℃ 이하에서 CO 전환율이 급격하게 저하되는 것을 확인하였다. 또한125 ℃ 이하에서 CO 전환율을 나타내지 않았다. 125 ℃에서 NO의 주입을 차단하더라도 초기 CO 전환율의 회복이 확인되지 않았다. 이에 따라 NO 주입에 따른 다양한 분석을 수행하였다. 먼저, TPD 분석 결과, 촉매에 NO의 선흡착은 CO 흡착을 방해하였으며 흡착된 CO에서 CO2로의 전환탈착을 억제하는 것을 확인하였다. 다음으로, NO가 선흡착될 경우, 촉매의 산소전달능력을 감소함을 H2-TPR 분석을 통하여 확인하였다. 또한 FT-IR 분석을 통하여, 촉매의 redox cycle (Pt2+→Pt0→Pt2+)을 방해하는 것을 확인하였다. 따라서 Pt/TiO2 촉매에서 NO의 존재는 CO 산화반응에서의 피독 인자으로 작용을 하였으며, NO 피독을 방지하기 위해서는 촉매의 산소전달능력의 증진이 필요하다고 판단되어진다.

Keywords

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