Kinetic studies of carbon nanofibre and hydrogen evolution via ethane decomposition over fresh and steam regenerated Ni/La2O3 catalyst

The co-precipitated Ni/La2O3 catalyst had low total surface area and adsorption–desorption isotherm of nearly type II. The X-ray diffractogram demonstrates that NiO, LaNiO3, and La2O3 were the phases present in Ni/La2O3 catalyst. The decomposition of ethane over Ni/La2O3 catalyst has been investigated using temperature-programmed reaction (TPRn). TPRn profile exhibited both low temperature and high temperature range of carbon deposition and indicated the production of H2 and CH4 in the gas phase from decomposition of ethane. Methane may be evolved from hydrogenation of surface methyl group from the decay of ethylidyne intermediate. The content, type of carbon, and kinetics of reaction of carbon with oxygen were determined by using temperature-programmed oxidation (TPO). Succeeding the regeneration of Ni/La2O3 catalyst after carbon deposition for three times with steam, this catalyst exhibited the similar TPRn spectra and had still initial activity toward ethane decomposition and carbon nanofibres production. Results of isothermal gasification of carbon nanofibres with steam at temperatures of 823–923 K showed that most of the carbon nanofibres are removed during reaction with steam.

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► The co-precipitated Ni/La2O3 as catalyst for stepwise steam reforming of ethane.
► NiO, LaNiO3, and La2O3 phases are present in catalyst.
► The similar TPRn spectra and initial activity toward ethane decomposition for four times.
► Steam gasification can be as potential routes for the regeneration of Ni/La2O3 catalyst.
► Ni/La2O3 catalyst could be a good candidate for use as a steam reforming catalyst.