Effects of precipitants on the catalytic performance of Cu/CeO2 catalysts for the water–gas shift reaction

Abstract

The water–gas shift (WGS) reaction has been attracting interest for on-site small-scale production of hydrogen. This study discusses the fabrication of inexpensive, high-performance Cu/CeO₂ catalysts. To synthesize these catalysts, CeO₂ supports were prepared using K₂CO₃/KOH as precipitants in different ratios. First, 20 wt% Cu was loaded onto the prepared CeO₂ supports through incipient wetness impregnation. The ratios of the precipitants affect the physicochemical properties of the Cu/CeO₂ catalysts, which in turn affects the catalytic performance. On increasing the K₂CO₃/KOH ratio, the surface area, oxygen storage capacity, and reducibility increased, while Cu dispersion decreased. To achieve high activity of Cu/CeO₂ catalysts, the CeO₂ support should be synthesized at the K₂CO₃ : KOH ratio of 3 : 1. This Cu/CeO₂ catalyst exhibits the highest CO conversion between 200 and 400 °C, even at a very high gas hourly specific velocity of 50 102 h⁻¹. This result shows that the catalytic performance is greatly influenced by various physicochemical properties such as surface area, oxygen storage capacity, Cu dispersion, and reducibility.