Methane steam reforming for hydrogen production using low water-ratios without carbon formation over ceria coated Ni catalysts

摘要

There are many advantages for hydrogen production from the catalytic methane steam reforming reaction(MSR)using low water to methane ratios.However,conventional Ni based catalysts suffer from severe carbon deposition under these conditions.A typical supported Ni catalyst at water to methane ratios<1 at 800°C shows rapid deactivation(within few hours).Incorporation of CeO2 is known to offer a kinetic resistance to carbon deposition for many hydrocarbon oxidation reactions because of its facilitated redox activity.As a result,a study of blending ceria into a supported Ni catalyst by a number of deposition methods has been carried out.Catalyst characterization including DRIFTS,XRD,TPR,TGA,TEM and EDX suggests the prime importance of an intimate contact between Ni and CeO2 in reducing the extent of carbon deposition during the reforming reaction,which critically depends on the preparation method in catalyst synthesis.As a result,a stable and high level of hydrogen production with no significant carbon deposition for over 110 h is demonstrated over the same Ni commercial catalyst pre-coated with ceria using a sol-gel method,which offers the best interface for the reaction.