Steam-biogas reforming over a metal-foam-coated (Pd–Rh)/(CeZrO2–Al2O3) catalyst compared with pellet type alumina-supported Ru and Ni catalysts

• SBR, SMR and DMR processes were experimentally evaluated with a focus on reactant conversion and product distribution.
• The Pd–Rh catalyst performed better than the commercial catalysts for SBR and other reforming processes.
• Net CO2 reduction was achieved over Pd–Rh catalyst at temperatures above 1010 K.

Metal-foam-coated 0.09 wt% [Pd(7)–Rh(1)]/(CeZrO2–Al2O3) catalyst was compared with commercially available alumina-supported 8.0 wt% Ru and 13.0 wt% Ni catalysts for steam reforming of a model biogas. The experiments were conducted in a tubular reactor using a feedstock with the steam-to-methane ratio of 1.50 at 1 atm pressure and 20,000 h−1 GHSV. CH4 reforming reactions by steam alone and by CO2 alone were also studied over these catalysts in order to explain the catalyst activity. The Pd–Rh catalyst is superior in a number of ways, including better activity for CH4 and CO2 conversion in spite of much less ingredient loading per unit volume. The Pd–Rh catalyst also exhibited higher syngas production index [(H2 LHV + CO LHV)/(Feed CH4 LHV)], lower syngas H2/CO ratio and coke formation. The results were supported by BET measurement, CO chemisorption and electron microscopy. The experimental results demonstrate that the metal-foam-coated Pd–Rh/(CeZrO2–Al2O3) catalyst performs better for syngas production through steam-biogas reforming compared to the Ru and Ni catalysts.