WGS reaction over nanostructured CuO–CeO2 catalysts prepared by hard template method: Characterization, activity and deactivation

This study focuses on water–gas shift reaction (WGSR) activity of CuO–CeO2 catalysts containing 10, 15 and 20 mol% CuO synthesized by hard template method with KIT-6 silica acting as a template. The obtained solids were characterized by N2 adsorption/desorption, XRD, H2-TPR/TPD, N2O decomposition, in situ DRIFTS and NH3 chemisorption/TPD methods. The catalysts exhibited ordered mesoporous structure, which was identified as the negative replica of KIT-6 silica pore system with CuO dispersion values between 28 and 40%. H2-TPR/TPD experiments revealed facile and extensive CeO2 reduction in tested samples, which increased with CuO loading, indicating strong interactions between both oxide phases. On the other hand, abundance of surface acidic sites decreased with increasing CuO content. WGS reaction activity was tested at the stoichiometric CO/H2O ratio and low contact times in the temperature range from 250 to 450 °C. At reaction temperatures above 375 °C, catalyst deactivation was observed, regardless of CuO content. Despite rigorous reaction conditions, CO conversion up to 62% was attained, with H2 selectivity above 99% in the entire temperature range.