학술논문
Hydrogenative CO2 Conversion using Nanoporous Spinel Oxide-Based Catalysts / 나노다공성 스피넬 산화물 기반 촉매를 이용한 이산화탄소 수소화 반응 연구
Document Type
Dissertation/ Thesis
Author
Source
Subject
Language
English
Abstract
대기 중의 CO2 농도는 여러 환경 문제를 야기할 만큼 이미 많이 증가되어 왔다. 세계의 많은 연구자들은 CO2 배출을 줄이고, 대기 중의 CO2 농도를 줄이기 위한 많은 노력을 한다. CO2를 고부가가치 화합물로의 전환은 연구자들의 많은 관심을 끌어당긴다. CO2 전환으로부터 생산되는 화합물들은 CO, 메탄올, 메탄, 탄화수소들이다. CO2를 탄화수소로 전환하는 반응에는 두 가지 경로들이 있다. 한 경로는 메탄올을 경유한다. 다른 하나의 경로는 CO를 경유한다. 열역학적 이점 때문에 CO를 경유하는 경로가 선호된다. 이 경로는 CO2가 CO로 전환되고, 그 CO는 탄화수소로 전환된다. 앞선 연구에서, CO2를 CO로 전환하는 촉매들을 연구하였다. 다양한 종류의 스피넬 산화물들(ZnAl2O4, CuAl2O4, CoAl2O4, MgAl2O4)을 준비하였다. 다양한 종류의 스피넬 산화물들을 이용한 RWGS 반응을 수행하였다. CuAl2O4 촉매가 높은 CO2 전환과 CO 선택성을 가지는 것을 확인하였다. 나아가, CuAl2O4 지지체에 Fe, K을 Loading한 다기능의 K-promoted Fe/CuAl2O4 촉매를 개발하였다. 22Fe3K/CuAl2O4 촉매는 다양한 탄화수소들을 CO2로부터 생산했다. 특히 22Fe3K/CuAl2O4 촉매는 높은 C5+ 생산성을 보여주었다. 이 연구에서는, CuAl2O4 촉매를 이용한 RWGS 반응에서 CuAl2O4의 촉매적 특성을 연구하였다. 그리고 CuAl2O4의 구조적 특성이 22Fe3K/CuAl2O4 촉매를 이용한 CO2 수소화 반응에 미치는 영향을 연구했다. 마지막으로, CO2 수소화 반응에 촉진제 금속의 효과를 연구했다. 첫 번째, 합성 변수들이 조절된 CuAl2O4 촉매들을 준비했다. 두 번째, 앞서서 준비된 촉매를 이용해 22Fe3K/CuAl2O4 촉매들을 준비했다. 세 번째, 다양한 프로모터 금속들을 이용한 22Fe3M/CuAl2O4 촉매들을 준비했다. 세 카테고리의 촉매들을 구조적 특성을 확인하기 위해 X-선 회절(XRD), N2 흡착-탈착 등온선, CO2-TPD, H2-TPR 그리고 ICP-OES 분석을 실시했다. 그리고 촉매들을 이용한 CO2 수소화 반응들을 수행했다. CuAl2O4 촉매들의 합성 변수들은 CuAl2O4 촉매들의 상과 그 함량, 결정성 그리고 결정 크기에 영향을 주었다. 준비된 CuAl2O4 촉매들을 이용한 RWGS 반응의 결과들은 그 촉매들의 비표면적과 염기성에 영향을 받았다. CuAl2O4의 구조적 특성들은 22Fe3K/CuAl2O4 촉매들을 이용한 CO2 수소화 반응 결과들에도 영향을 주었다. 또한, 탄화수소를 생산하는 CO2 수소화 반응은 프로모터 금속들에 영향을 받는다. 우리는 촉매들의 특성들과 반응 결과들 사이의 상관관계를 확인했다.
The concentration of CO2 in the atmosphere has increased so much that it causes several environmental problems. Many researchers around the world are making great efforts to reduce the concentration of CO2 in the atmosphere and CO2 emissions. The conversion of CO2 to high-value compounds attracts a lot of attention from researchers. The compounds produced from the CO2 conversion are CO, methanol, methane, and hydrocarbons. There are two pathways for converting CO2 to hydrocarbons. One pathway is via methanol. The other pathway is via CO. The route via CO is preferred because of its thermodynamic advantages. This pathway consists of the reverse water-gas shift (RWGS) reaction to convert CO2 to CO and Fischer-Tropsch synthesis (FTS) to convert CO to hydrocarbons. In a previous study, Catalysts were studied for CO2 conversion to produce CO. Various kinds of mesoporous spinel oxides (ZnAl2O4, CuAl2O4, CoAl2O4, MgAl2O4) were prepared. The RWGS reactions were performed using them. It was confirmed that the CuAl2O4 catalyst has high CO2 conversion and CO selectivity. Furthermore, a multifunctional K-promoted Fe/CuAl2O4 catalyst loaded Fe and K on the CuAl2O4 as support was prepared. The 22Fe3K/CuAl2O4 catalyst converts CO2 to various hydrocarbons. In particular, the 22Fe3K/CuAl2O4 catalyst showed high C5+ productivity. In this study, the catalytic properties of the CuAl2O4-based catalysts in the RWGS reaction were investigated. And the effect of the structural properties of the CuAl2O4 as a support was studied in the CO2 hydrogenation reaction using the 22Fe3K/CuAl2O4 catalysts. Finally, the effects of the promoter metals in the CO2 hydrogenation reaction are investigated. First, the CuAl2O4 catalysts with controlled synthesis parameters were prepared. Second, the 22Fe3K/CuAl2O4 catalysts using the previously prepared catalysts as supports were prepared. Third, the 22Fe3M/CuAl2O4 catalysts were prepared by using various promoter metals. The prepared catalysts are analyzed by N2 adsorption-desorption isotherm, inductively coupled plasma optical emission spectroscopy (ICP-OES), CO2 temperature-programmed desorption (TPD), H2 temperature-programmed reduction (TPR), and X-ray diffraction (XRD). The CO2 hydrogenation reactions were performed using the prepared catalysts. The synthetic parameters of CuAl2O4 catalysts affected the phase, content, crystallinity, and crystal size of catalysts. The results of the RWGS reaction using the prepared CuAl2O4 catalysts were affected by the basicity and the specific surface area of the catalysts. The structural properties of CuAl2O4 also influenced CO2 hydrogenation to produce hydrocarbons using the 22Fe3K/CuAl2O4 catalysts. Additionally, the CO2 hydrogenation reaction to produce hydrocarbons is affected by promoter metals. The correlation between the reaction results and the properties of the catalysts was confirmed.
The concentration of CO2 in the atmosphere has increased so much that it causes several environmental problems. Many researchers around the world are making great efforts to reduce the concentration of CO2 in the atmosphere and CO2 emissions. The conversion of CO2 to high-value compounds attracts a lot of attention from researchers. The compounds produced from the CO2 conversion are CO, methanol, methane, and hydrocarbons. There are two pathways for converting CO2 to hydrocarbons. One pathway is via methanol. The other pathway is via CO. The route via CO is preferred because of its thermodynamic advantages. This pathway consists of the reverse water-gas shift (RWGS) reaction to convert CO2 to CO and Fischer-Tropsch synthesis (FTS) to convert CO to hydrocarbons. In a previous study, Catalysts were studied for CO2 conversion to produce CO. Various kinds of mesoporous spinel oxides (ZnAl2O4, CuAl2O4, CoAl2O4, MgAl2O4) were prepared. The RWGS reactions were performed using them. It was confirmed that the CuAl2O4 catalyst has high CO2 conversion and CO selectivity. Furthermore, a multifunctional K-promoted Fe/CuAl2O4 catalyst loaded Fe and K on the CuAl2O4 as support was prepared. The 22Fe3K/CuAl2O4 catalyst converts CO2 to various hydrocarbons. In particular, the 22Fe3K/CuAl2O4 catalyst showed high C5+ productivity. In this study, the catalytic properties of the CuAl2O4-based catalysts in the RWGS reaction were investigated. And the effect of the structural properties of the CuAl2O4 as a support was studied in the CO2 hydrogenation reaction using the 22Fe3K/CuAl2O4 catalysts. Finally, the effects of the promoter metals in the CO2 hydrogenation reaction are investigated. First, the CuAl2O4 catalysts with controlled synthesis parameters were prepared. Second, the 22Fe3K/CuAl2O4 catalysts using the previously prepared catalysts as supports were prepared. Third, the 22Fe3M/CuAl2O4 catalysts were prepared by using various promoter metals. The prepared catalysts are analyzed by N2 adsorption-desorption isotherm, inductively coupled plasma optical emission spectroscopy (ICP-OES), CO2 temperature-programmed desorption (TPD), H2 temperature-programmed reduction (TPR), and X-ray diffraction (XRD). The CO2 hydrogenation reactions were performed using the prepared catalysts. The synthetic parameters of CuAl2O4 catalysts affected the phase, content, crystallinity, and crystal size of catalysts. The results of the RWGS reaction using the prepared CuAl2O4 catalysts were affected by the basicity and the specific surface area of the catalysts. The structural properties of CuAl2O4 also influenced CO2 hydrogenation to produce hydrocarbons using the 22Fe3K/CuAl2O4 catalysts. Additionally, the CO2 hydrogenation reaction to produce hydrocarbons is affected by promoter metals. The correlation between the reaction results and the properties of the catalysts was confirmed.