La2Ce2O7 Carrier Catalyst for Prominent Steam Reforming Conversion from Medical Waste Pyrolysis Gas to Hydrogen

Abstract

An efficient catalyst was studied for the steam reforming reaction of the simulated pyrolysis gas from medical waste (MW) in this paper. The impact of Rh supported on different carrier catalysts on the MW pyrolysis steam reforming performance was investigated. In order to acquire the optimum conditions for hydrogen generation, the impact of reaction temperature, steam/medical waste pyrolysis gas ratio, and gas hourly space velocity on hydrogen production efficiency was studied in the steam reforming reaction. Notably, the reforming and stability performance of 1 wt%Rh/La₂Ce₂O₇ surpassed those of 1 wt%Rh/Al₂O₃. The former achieved an approximately 60% H₂ content and sustained stable hydrogen increment (I_H2) and hydrogen selectivity (S_H2) values around 520% and 99.5–99.7%, respectively. Moreover, the conversions for C₁–C₅ (X_i) all exceeded 98%. 1 wt%Rh/La₂Ce₂O₇ has such prominent catalytic performance because H₂-TPR and XPS results show that RhO_x species were more reducible, and more Rh active species are formed due to strong interaction between Rh and the La₂Ce₂O₇ carrier, which are helpful to the hydrocarbon species adsorption to form intermediate CH* species on Rh metal sites. Besides, the high concentration of oxygen vacancies and active oxygen species on the 1 wt%Rh/La₂Ce₂O₇ catalyst enhanced the adsorption and activation of H₂O to form intermediate O*, which facilitates the timely oxidation of intermediate CH* species on the Rh metal surface, ultimately alleviating catalyst surface carbon deposition.