Promotion of methanation suppression by alkali and alkaline earth metals in Ni-CeO2 catalysts for water–gas shift reaction using waste-derived synthesis gas

Abstract

In this study, alkali and alkaline earth metal-promoted Ni-CeO2 catalysts were developed for the high-temperature water–gas shift reaction of waste-derived synthesis gas in which hydrogen is produced. The elements K, Ca, Mg, and Ba were selected to repress methanation, which is a major side reaction of Ni-based catalysts. The prepared catalysts were characterized using different techniques including the Brunauer–Emmett–Teller method, X-ray diffraction, H2-temperature programmed reduction, CO2-temperature programmed desorption, H2-chemisorption, and X-ray photoelectron spectroscopy to determine the correlations between the catalyst activity and their properties. The results show that the alkali and alkaline earth metal-promoted Ni-CeO2 catalyst effectively suppressed methanation. Among the promoted catalysts, the Ca/Ni-CeO2 catalyst exhibited the highest activity and stability for 18 h at a very high gas hourly space velocity of 1,050,957 h−1, which is mainly due to the high oxygen storage capacity.