수소혼합물에 포함된 CO의 선택적 산화반응에서 CuO-CeO2 촉매와 chlorine이 첨가된 CuO-CeO2 촉매의 활성비교 = Selective CO oxidation on CuO-CeO2 and chlorine induced-CuO-CeO2 catalyst in the H2-rich gas mixture

다국어 초록 (Multilingual Abstract)

A series of CuO-CeO2 catalysts with Cu content in the range of 5~50 at% (the atomic percent of Cu/(Cu+Ce)) were prepared by co-precipitation method. The catalysts were tested for CO oxidation and selective CO oxidation with CO2, H2O and excess H2. The catalysts were highly active in the CO oxidation and also active and remarkably selective in the selective oxidation. CO2 and H2O, however, decreased the catalyst activity; between CO2 and H2O, H2O decreased the activity more than CO2. Among the catalysts, the 10 at%
Cu catalyst outperformed all the other catalysts in the CO oxidation without CO2 and H2O in the feed, whereas the 20 at% Cu exhibited the highest activity in the selective CO oxidation. This change in the optimum Cu content
could be ascribed to the adverse effect of H2O on the activity that was dependent on the Cu content of the catalysts.
CeO2 supported 3 wt% Cu catalysts were prepared from a chloride containing Cu precursor, a nitrate Cu precursor and a combination of both precursors. The catalysts were tested for the selective CO oxidation in the presence of excess hydrogen to investigate the effect of the chloride content on the catalytic performance. The residual chloride was found to affect the activity in three different ways: (i) it enhanced the dispersion of Cu particles, (ii) it reduced the CO2 inhibition by hindering formation of surface carbonate species, and (iii) it inhibited the catalytic activity by impeding the oxygen mobility on the surface. The increased Cu dispersion was beneficial to the activity and independent of the chloride content from 0.18 ~ 0.76 wt%. With increasing chloride content, however, the CO2 inhibition effect as well as the activity decreased. The decrease in the CO2 inhibition alone would make the catalyst perform better in the presence of CO2, but the decrease in the activity due to the impediment of the oxygen mobility more than offset the beneficial effect of the decreased CO2 inhibition with increasing chloride content. As a result of the combined effects of the chloride, the activity experiments showed that among the tested catalysts, the catalyst containing 0.18 wt% chloride outperformed other catalysts in the selective CO oxidation.

목차 (Table of Contents)

• 목차 i
• 표목록 ii
• 그림목록 iii
• 1. 서론 1
• 2. 실험 5
• 2.1. 촉매제조 5
• 2.1.1. 공침법 5
• 2.1.2. 함침법 6
• 2.2. 실험장치 및 방법 10
• 2.2.1. 유량조절부 10
• 2.2.2. 선택적 산화 반응기 12
• 2.2.3. 반응생성물 분석 12
• 2.3. 촉매 특성 분석 15
• 2.3.1. H2-TPR 15
• 2.3.2. CO2, H2O-TPD 15
• 3. Cu 함량에 따른 CuO-CeO2 촉매의 활성 17
• 3.1. Surface area와 XRD pattern 17
• 3.2. H2-TPR 19
• 3.3. 순수한CO산화반응 22
• 3.4. H2, H2O, CO2의 존재 하에서 선택적CO산화반응 24
• 3.5. H2O, CO2 존재 하에서 순수한CO산화반응 28
• 3.6. H2O, CO2 존재 하에서 순수한 수소산화반응 31
• 4. CuO-CeO2 촉매에 첨가된 chlorine 영향 34
• 4.1. Characteristics of the Cu catalysts 34
• 4.2. CO2, H2O-TPD 38
• 4.3. H2-TPR 42
• 4.4. Cu 함량에 따른 CuO-CeO2 촉매의 활성 45
• 4.5. 순수한CO산화반응에서 chlorine 영향 47
• 4.6. H2O, CO2 존재 하에서 순수한CO산화반응 49
• 4.7. H2, H2O, CO2의 존재 하에서 선택적CO산화반응 53
• 5. 결론 56
• 6. 참고문헌 58
• 영문 초록 62
• 표 목 록
• Table 1. Gas Chromatography operating condition 13
• Table 2. Characteristics of the Cu catalysts. 36
• 그림목록
• Fig. 1. Scheme of co-precipitation method 8
• Fig. 2. Scheme of impregnation method 9
• Fig. 3. Schematic diagram of the apparatus 11
• Fig. 4. Typical Chromatogram 14
• Fig. 5. XRD profiles for CuO-CeO2 catalysts with various Cu loading 18
• Fig. 6. TPR profiles with various reducing mixtures
• on the CuO-CeO2 catalyst 21
• Fig. 7. Effect of Cu loading in CuO-CeO2 catalyst
• on CO oxidation activity 23
• Fig. 8. CO conversion and selectivity vs. temperature 26
• Fig. 9. Effect of Cu loading on CO conversion
• in selective CO oxidation 27
• Fig. 10. CO conversion versus temperature in CO oxidation
• without CO2 and H2O, with CO2 or with H2O
• over 10 at% CuO-CeO2 and 20 at% CuO-CeO2 30
• Fig. 11. O2 conversion versus temperature in H2 oxidation
• without CO2 and H2O, with CO2 or with H2O
• over 10 at% CuO-CeO2 and 20 at% CuO-CeO2 33
• Fig. 12. XRD patterns of CuO-CeO2 catalysts
• with various chlorine content 37
• Fig. 13. CO2-TPD profiles for various chlorine content
• in the 3 wt% CuO-CeO2 40
• Fig. 14. H2O-TPD profiles for various chlorine content
• in the 3 wt% CuO-CeO2 41
• Fig. 15. TPR profiles with various reducing mixtures
• on the CuO-CeO2 catalyst 44
• Fig. 16. Effect of different Cu loading in CuO-CeO2 catalyst
• on CO oxidation activity 46
• Fig. 17. Effect of various chlorine content in CuO-CeO2 catalyst on CO oxidation activity 48
• Fig. 18. CO conversion vs. temperature in CO oxidation with various chlorine contained CuO-CeO2 catalysts with CO2 or with H2O 51
• Fig. 19. CO conversion with various chlorine content
• in CO oxidation with CO2 or H2O 52
• Fig. 20. Effect of chlorine in the CuO-CeO2 catalyst
• in selective CO oxidation 54
• Fig. 21. Selectivity for various chlorine contained
• CuO-CeO2 catalysts 55