Dry Reforming of Methane over Ni-based LDH Catalyst: effect of H2S and O2

The extensive utilization of fossil fuels needed to meet the increasing global energy demand associated with population growth has led to major environmental challenges worldwide. Environmental pollution, global warming and extreme weather events are among the main consequences linked to anthropogenic greenhouse gas emissions. Among these gases, CH4 and CO2 play a particularly important role due to their large emissions and global warming potential. A possible strategy, to mitigate their effects, could be the Dry Reforming of Methane reaction (DRM) which converts these greenhouse gases into syngas, a mixture of CO and H2 that serves as key intermediate to produce important chemicals in the industry. CH4 and CO2 can be obtained from the anaerobic digestion of waste biomass dealing at the same time with these abundant pollutants and with waste valorization. One of the main challenges associated with this process is that depending on the feed, impurities such as H2S and O2 can be present in the outlet gas of the anaerobic digestion reactor. The aim of this work is to synthesize and evaluate the behavior of different catalysts for the DRM reaction under this unconventional feed. Five catalysts were synthesized by the co-precipitation method, characterized by XRD, XRF, SEM-EDS, H2-TPR, N2-physisorption, TGA and tested in a quartz tube reactor. Among the investigated catalysts, 10Ni0.5Co-LDH exhibited the highest sulfur resistance and regeneration efficiency. In contrast, the Cu-promoted catalyst displayed the lowest sulfur tolerance and the highest irreversible activity loss. Overall, the results demonstrate that the addition of suitable promoter metals can significantly enhance catalyst durability under sulfur-containing reforming conditions, making these materials promising candidates for the upgrading of biomass-derived gas streams and the sustainable production of syngas for downstream fuel synthesis.