Hydrogen production from the oxidative steam reforming of methanol over Au/CeO2 catalysts

Abstract

The production of hydrogen by the oxidative steam reforming of meth (OSRM) was investigated on a series of Au/CeO₂ catalysts prepared by depoesition-precipitation. The influences of the main parameters considered on the methanol conversion are the H₂O/CH₃OH and O₂/CH₃OH feed molar ratios, content of Au loading, calcination temperature, and operating reaction temperature. Among all the samples studied, l%wt Au/CeO₂ exhibited nearly a 100 % methanol conversion and 23.63% H₂ yield at 300 ℃. Optimum operating conditions— GHSV = 30,000 ml/ h- gcat, T = 300 ℃, H₂O/CH₃OH molar ratio = 2/1, and O₂/CH₃OH molar ratio = 1.25/1 — could be suggested to obtain the high methanol conversion and hydrogen yield. Interestingly, 5% wt Au/ CeO₂ exhibited the highest activity under the optimum conditions with 100% methanol conversion and 24.5% H₂ yield since larger Au particle sizes might be more active in OSRM without metal sintering during the reaction. In the stability test, methanol conversion dropped rapidly from 100% to 88.8 % after 40 h due to a blocking of pores by coke formation; whereas an average H₂ yield at 16.12% was still steady.