Development of catalysts for hydrogen production through the integration of steam reforming of methane and high temperature water gas shift

摘要

There is great concern about the increasing demand for energy with respect to carbon emissions, but hydrogen (H-2), a clean fuel, could help alleviate this concern. The replacement of fossil fuels with H-2 is cost prohibitive, but integration of SRM (steam reforming of methane) and WGS (water gas shift) could greatly decrease production costs. A composite catalyst of nickel, cerium, zirconium, and zinc was designed to provide activity in both the SRM and WGS reactions. The catalysts were characterized by a variety of techniques including BET (Brunauer Emmett Teller), TEM (transmission electron microscopy), SEM (scanning electron microscopy), TGA (thermogravimetric analysis), and XRD (X-ray diffraction). It was found that the addition of zinc decreased the surface area, and therefore activity of the SRM reaction, although it increased WGS activity as observed by improved carbon dioxide selectivity and H2 production. Zinc also increased resistance to carbon deposition. Additionally, aging of precipitates during catalyst synthesis improved stability. A Ce/Zr/Zn catalyst doped with 10% Ni and aged for 2 h was found to have a final conversion of nearly 20% at 650 degrees C, and high CO2 selectivity around 55%. This catalyst is an important step in the emerging field of low temperature SRM, a field that could lead to a reduction in carbon emissions. (C) 2015 Elsevier Ltd. All rights reserved.