Clean Technology, Vol.24, No.1, 35-40, March, 2018
N2O 분해반응용 Co3O4 기반 촉매의 K첨가 효과
K Addition Effect of Co3O4-based Catalyst for N2O Decomposition
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초록
N2O 촉매 분해 반응을 위한 Co3O4 촉매는 공침법을 이용하여 제조하였으며, 조촉매로서 Ce 및 Zr의 양을 (Ce 또는 Zr)/Co =0.05의 몰비로 고정하여 제조하였다. 또한 K가 촉매에 미치는 영향을 조사하기 위해 1 wt%의 K2CO3를 함침하여 촉매를 제조하였다. 제조된 촉매의 특성은 BET, SEM, XRD, H2-TPR, XPS를 통해 분석하였다. Co3O4 촉매는 스피넬 결정상을 나타냈으며, 조촉매의 첨가는 입자 크기와 결정 크기를 감소시켜 비표면적을 증가시키는 것으로 나타났다. K의 도핑은 촉매 활성 물질인 Co의 활성 종인 Co2+의 농도를 증가시켜 촉매 활성을 향상시키는 것으로 확인되었다. N2O 분해 반응 테스트는 GHSV = 45,000 h-1, 250 ~ 375 ℃에서 수행되었으며 Co3O4 촉매에 조촉매를 첨가하였을 때도 반응성이 증가하였지만, K를 함침하면 활성이 더욱 크게 증가하는 것으로 나타났다. K의 도핑이 활성 종인 Co2+의 농도를 증가시키며, 환원온도를 낮춰 주어 활성에 큰 영향을 주는 것으로 확인하였다.
Co3O4 catalysts for N2O decomposition were prepared by co-precipitation method. Ce and Zr were added during the preparation of the catalyst as promoter with the molar ratio (Ce or Zr) / Co = 0.05. Also, 1 wt% K2CO3 was doped to the prepared catalyst with impregnation method to investigate the effect of K on the catalyst performance. The prepared catalysts were characterized with SEM, BET, XRD, XPS and H2-TPR. The Co3O4 catalyst exhibited a spinel crystal phase, and the addition of the promoter increased the specific surface area and reduced the particle and crystal size. It was confirmed that the doping of K improves the catalytic activity by increasing the concentration of Co2+ in the catalyst which is an active site for catalytic reaction. The catalytic activity tests were carried out at a GHSV of 45,000 h-1 and a temperature range of 250 ~ 375 ℃. The K-impregnated Co3O4 catalyst showed much higher activity than Co3O4 catalysts with promoter only. It is found that the K-impregnation increased the concentration of Co2+ more than the added of promoter did, and lowered the reduction temperature to a great extent.
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