Suspension-washcoat optimization for preparing copper-manganese oxide structured catalyst towards flue gas CO purification

Abstract

Structured catalysts play significant role in nowaday environmental industry. The copper-manganese oxide (Cu-Mn) is a low cost and efficient catalyst for CO purification from flue gas, for which a robust preparation regarding stabilized suspension and washcoat process is still lacked. This work addressed this challenge by constructing the catalyst suspension by introducing absorbent polymer (SAP), polyvinyl alcohol (PVA), and nano-silica sol (SiO2-NA). The effects of the dosage of SAP, PVA, and SiO2-NA on suspension properties including viscosity, water-retention capacity and stability were systematically studied. The combined effect of the three additives regarding electrostatic-sterical stability and regionalized coating is demonstrated to avoids the destruction of connection between SiO2-NA and Cu-Mn due to the thermal stress during the drying process. After calcination, SiO2-NA is efficiently utilized, evenly distributed and tightly bonded to Cu-Mn catalyst, rendering strongly-attached, crack-free and compact washcoated layer. The optimized structured catalyst shows appreciable balance of loading (up to 182kg/m3) and strength (powder shedding rate <1wt%) without blockage. The potential of practical application was verified by CO purification from realistic iron-ore sintering flue gas with catalytic efficiency of above 90% for 240h. These findings indicated a promising strategy to design Cu-Mn structured catalysts efficient for industrial use.