High-purity H2 production by sorption-enhanced water gas shift on a K2CO3-promoted Cu/MgO–Al2O3 difunctional material

Abstract

Sorption-enhanced water gas shift (SEWGS) that combines WGS and in situ CO₂ removal is a promising technology for production of high-purity H₂. However, it is a challenge to develop effective difunctional materials (DFMs) for the SEWGS process. Here, we prepared a novel type of K₂CO₃-promoted Cu/MgO–Al₂O₃ DFMs by a sol–gel method. In situ DRIFTS demonstrated that the WGS reaction and adsorption of produced CO₂ occurred simultaneously on the DFM. The composition-property-performance studies showed that the K/(Mg + Al) and Mg/Al atomic ratios have effects on the physicochemical properties of DFM, especially the morphology and the basicity distribution, which in turn affected the CO₂ adsorption performance. In addition, the regeneration temperature of DFM used in cyclic operation was found to influence the SEWGS performance. The best DFM with a K/(Mg + Al) ratio of 0.2 and a Mg/Al ratio of 9 can completely convert CO and yield >99.9% H₂ in 10 consecutive SEWGS-regeneration cycles between 300 °C (for SEWGS) and 380 °C (for regeneration).