TITLE:
Production of Carbon Nanotubes and Hydrogen Catalyzed with Ni/MCM-41 Catalysts
AUTHORS:
Zhiqi Wang, Juan Navarrete
KEYWORDS:
Methane Catalytic Decomposition; Hydrogen, Carbon Nanotubes; Catalysts; Ni/MCM-41
JOURNAL NAME:
Green and Sustainable Chemistry,
Vol.2 No.3,
August
20,
2012
ABSTRACT: Methane catalytic decomposition (MCD) over Ni/MCM-41 catalysts was tested in a microreactor to simultaneously produce hydrogen and carbon nanotubes (CNTs). The methane conversion reached 30% to 47% at a moderate temperature range from 400°C to 600°C and the catalytic activity of the catalysts remains stable during 500 min steam on time. CNTs were chiefly formed through tip-growth mode, due to the weak interaction between the metallic Ni and the support. Most of the Ni particles are located on the tip of the produced CNTs, which avoids rapid deactivation of the catalyst resulted from carbon encapsulation. Large Ni particles usually lead to the formation of CNTs with big diameter. During the reaction, the shape of Ni particles changed from pseudo-sphere to diamond-like. All the CNTs consist of multiple layer walls and are curved in certain degree.