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Changes on texture and crystalline phase of activated carbon-supported NI-Ca catalyst during dry methane reforming

Abstract:

Changes on texture and crystalline phase of AC-supported Ni-Ca catalyst during dry methane reforming were verified. Characterization by N2 adsorption, XPS, XRD, TEM and HR-TEM was performed. XPS and XRD analysis suggest that the initial activity can be attributed to a nickel reduced phase formed during helium pre-treatment. TEM showed that a homogeneous distribution of Ni nanoparticles between 10-20nm at the tip of multi-walled carbon nanotubes is formed during reaction. HR-TEM showed diffusion of Ni nanoparticles and the formation of carbon-like nano onions with an interlayer separation of 0.5nm suggesting the formation of a ultra-microporous carbon structure. An increase in surface area from 231m2.g-1 to 2405m2.g-1 after 90min reaction was found and attributed to an in situ activation of carbon deposits by CO2 gasification. The present results suggest that introducing CO2 pulses during reaction carbon-supported Ni-Ca could be employed as potential catalysts for methane and other hydrocarbon reforming reactions at mild experimental conditions. © Matos et al.