Highly stable and active catalyst for hydrogen production from biogas

• We used a La-promoted catalyst obtained from a hydrotalcite precursor.
• The catalyst was tested for dry reforming of methane to syngas during 300 h.
• No sign of deactivation was detected, although carbon deposited.
• The deposited carbon consists of carbon nanotubes and nanofibres with defects in their structure.

A La-NiMgAlO catalyst, obtained after calcination of a hydrotalcite precursor, was evaluated in dry reforming of methane. The catalyst showed no sign of deactivation during a 300 h test. CH4 and CO2 conversion were higher than thermodynamic equilibrium estimation which suggests the participation of other reactions.Used catalyst was characterized by several techniques (TPO, XPS and Raman spectroscopy and SEM and TEM microscopy) in order to establish whether carbon was deposited and its nature. Two different types of carbon were present: carbon nanotubes (CNTs) and carbon nanofibres (CNFs). These filamentous carbons were well-crystallize but with many structural defects, which can increase the resistivity to fracture and therefore prevent the encapsulation of active sites. In addition, graphite can act as a CHx collector, limiting the deactivation process. The small Ni particles diameter, together with its broad distribution, seems to have also a beneficial effect on the catalytic performance.