Impacts of La addition on formation of the reaction intermediates over alumina and silica supported nickel catalysts in methanation of CO2

Chuanfei Liang, Tao Wei, Hui Wang, Zhengjie Yu, Dehua Dong, Shu Zhang, Qing Liu, Guangzhi Hu, Xun Hu

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27 Citations (Scopus)

Abstract

This study aimed to investigate impacts of Al2O3 and SiO2, the supports of Ni catalysts with distinct properties, and the additive of La on catalytic behaviors and reaction intermediates formed during methanation of CO2. The results showed that the addition of La to either Ni/Al2O3 or Ni/SiO2 led to the reduced size of metallic nickel, the reduced reduction degree of nickel oxide, the increased alkalinity number and the increased activity for methanation of CO2. Furthermore, the addition of La to the Ni/SiO2 catalyst could suppress the formation of CO via the reverse water gas shift (RWGS) reaction. Ni/SiO2 was much more active than the Ni/Al2O3, even though nickel size was much bigger. The in situ Diffuse Reflection Infrared Fourier Transform Spectroscopy (DRIFTS) studies showed that the addition of La to Ni/Al2O3 interfered with integration of hydroxyl group with *CO2 species and formation of the bicarbonate and carbonate, while favored formation of the formate specie, enhancing the catalytic activity. For Ni/SiO2, instead of formate, CO* became the main reaction intermediate. The strong absorption of CO* favored its further conversion and explained the low selectivity of the silica-based catalysts toward CO. The addition of La to Ni/SiO2 catalyst facilitated further hydrogenation of CO* species to CH4 and promoted the catalytic activity.

Original languageEnglish
Pages (from-to)723-738
Number of pages16
JournalJournal of the Energy Institute
Volume93
Issue number2
DOIs
Publication statusPublished - Apr 2020
Externally publishedYes

Keywords

  • Different supports
  • In situ DRIFTS
  • La promoter
  • Methanation of CO
  • Reaction intermediates

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