Clean Technology (청정기술)

The Korean Society of Clean Technology (한국청정기술학회)
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Catalytic CO2 Methanation over Ni Catalyst Supported on Metal-Ceramic Core-Shell Microstructures

금속-세라믹 코어-쉘 복합체에 담지된 Ni 금속 촉매를 적용한 CO2 메탄화 반응 특성연구

  • Lee, Hyunju (Department of Chemical Engineering, University of Seoul) ;
  • Han, Dohyun (Department of Chemical Engineering, University of Seoul) ;
  • Lee, Doohwan (Department of Chemical Engineering, University of Seoul)
  • 이현주 (서울시립대학교 화학공학과) ;
  • 한도현 (서울시립대학교 화학공학과) ;
  • 이두환 (서울시립대학교 화학공학과)
  • Received : 2022.04.06
  • Accepted : 2022.05.06
  • Published : 2022.06.30
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Abstract

Microstructured Al@Al2O3 and Al@Ni-Al LDH (LDH = layered double hydroxide) core-shell metal-ceramic composites are prepared by hydrothermal reactions of aluminum (Al) metal substrates. Controlled hydrothermal reactions of Al metal substrates induce the hydrothermal dissolution of Al ions at the Al-substrate/solution interface and reconstruction as porous metal-hydroxides on the Al substrate, thereby constructing unique metal-ceramic core-shell composite structures. The morphology, composition, and crystal structure of the core-shell composites are affected largely by the ions in the hydrothermal solution; therefore, the critical physicochemical and surface properties of these unique metal-ceramic core-shell microstructures can be modulated effectively by varying the solution composition. A Ni/Al@Al2O3 catalyst with highly dispersed catalytic Ni nanoparticles on an Al@Al2O3 core-shell substrate was prepared by a controlled reduction of an Al@Ni-Al LDH core-shell prepared by hydrothermal reactions of Al in nickel nitrate solution. The reduction of Al@Ni-Al LDH leads to the exolution of Ni ions from the LDH shell, thereby constructing the Ni nanoparticles dispersed on the Al@Al2O3. The catalytic properties of the Ni/Al@Al2O3 catalyst were investigated for CO2 methanation reactions. The Ni/Al@Al2O3 catalyst exhibited 2 times greater CO2 conversion than a Ni/Al2O3 catalyst prepared by conventional incipient wetness impregnation and showed high structural stability. These results demonstrate the high effectiveness of the design and synthesis methods for the metal-ceramic composite catalysts derived by hydrothermal reactions of Al metal substrates.

알루미늄 (Al) 금속을 전구체 및 구조체로 이용, 수열 반응을 통하여 Al@Al2O3와 Al@Ni-Al LDH (LDH = layered double hydroxide) 코어-쉘 복합 구조체를 합성하였다. 제조된 구조체의 형상, 조성, 결정 구조는 수용액에 존재하는 이온들에 의하여 크게 영향을 받았으며, 이를 활용하여 다양한 특성의 촉매 구조체 유도가 가능하였다. Al@Ni-Al LDH 코어-쉘 구조체의 환원을 통하여 Ni 나노 입자가 고정화된 Ni/Al@Al2O3 촉매를 제조하였고, CO2 메탄화 반응에 적용하여 촉매의 특성을 평가하였다. Ni/Al@Al2O3 촉매는 전통적 incipient wetness impregnation 방법에 의하여 제조된 Ni/Al2O3 촉매에 비교하여 Ni 입자의 분산도와 균일성이 매우 높았으며 약 2 배 이상의 CO2 전환율로 높은 촉매적 활성과 더불어 구조의 안정성을 보여 주었다. 이러한 Ni/Al@Al2O3 구조체 촉매의 우수한 특성은 Al 금속을 기반으로 한 새로운 개념의 촉매 구조체 설계와 합성 방법의 타당성을 보여준다.

Keywords

Acknowledgement

이 논문은 2020년도 서울시립대학교 연구년교수 연구비 지원으로 연구되었으며, 부경대학교 화학공학과 우희철 교수님의 정년을 기념하여 투고되었습니다.

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