Kinetics of Oxidative Steam Reforming of Ethanol Over Bimetallic Catalysts Supported on CeO2–SiO2: A Comparative Study

Abstract

The catalytic activity of M(Ag, Ru, Pt)–Ni/CeO2–SiO2 catalysts prepared by wet impregnation at different M loadings (0–3 wt%) for oxidative steam reforming of ethanol (OSR) was investigated at H2O/C2H5OH = 4, O2/C2H5OH = 0.5, T = 300–600 °C and WHSV = 61.7 h−1. Ag deposition on the Ni/CeO2–SiO2 sample resulted in lower H2 yields, whatever the silver content. Conversely, Ru and Pt addition improved the performances of the monometallic sample and catalyst activity was enhanced by the reduction of metals loading. Similar results were recorded over the catalysts prepared at the same metals content and a metal loading of 0.5 wt% was sufficient to reach the highest performance in the investigated temperature interval. The kinetic model able to predict the experimental results obtained over the most promising formulations includes ethanol decomposition, methane oxidation and steam reforming, water gas shift; Pt as well as Ru addition to the Ni/CeO2–SiO2 sample reduced the activation energy of the involved reactions and Ru was demonstrated to be a valid substitute of the Pt for OSR of ethanol. Thus, by employing smaller noble metal content and less expensive materials, it is possible to reduce the catalyst price.