Mesoporous NiCu–CeO2 oxide catalysts for high-temperature water–gas shift reaction

Abstract

Mesoporous NiCu–CeO₂ oxide catalysts were synthesized by using the evaporation-induced self-assembly method applied to the high-temperature, water–gas shift reaction (HT-WGS) between 350 to 550 °C. Nickel and copper loadings on mesoporous ceria were tailored to achieve high activity and selectivity by suppressing methane formation in HT-WGS. Among the prepared catalysts, NiCu(1 : 4)–CeO₂ exhibited the highest selectivity to CO₂ and H₂ with 85% CO conversion at a very high GHSV of 83 665 h⁻¹. The higher activity of the catalysts was due to the mesoporous architecture, which provides more accessible active sites for the WGS reaction. Powder X-ray diffraction (XRD), small angle X-ray scattering (SAXS), N₂-adsorption/desorption isotherm, high-resolution transmission electron microscopy (HR-TEM), and H₂-temperature-programmed reduction (TPR) techniques were used to understand the role of mesoporosity and bimetallic composition of various NiCu–CeO₂ oxides in enhancing catalytic activity for HT-WGS.