Monitoring the influence of steam on highly-active rhodium catalyst during the combined reforming of biogas by transient and steady-state operando spectroscopic studies

The impact derived from incorporating water into CH₄/CO₂ biogas stream for the generation of syngas was investigated over the Rh/MgAl₂O₄ catalyst using operando steady-state and transient DRIFT spectroscopy coupled with MS. The incorporation of steam resulted in improved CH₄ conversion rates and attained syngas streams with higher H₂/CO ratios. It was demonstrated that in the presence of steam, the generation of CH_xO species through the reaction of CO* with active *OH species is favored at the metal support surface. Besides, the enhanced resistance delivered by water molecules towards deactivating the coking phenomena was associated with easier carbonaceous decomposition and the exposition of the very active Rh (100) surfaces for methane decomposition. The Rh/MgAl₂O₄ catalyst was demonstrated to be an effective catalyst for the production of H₂-rich syngas streams. More importantly, the insights reported herein provide new evidences regarding the impact of steam on biogas reforming reactions.