Pt/Re/CeO2 Based Catalysts for CO-Water-Gas Shift Reaction: from Powders to Structured Catalyst

This work focuses on the development of a Pt/Re/CeO2-based structured catalyst for a single stage water-gas shift process. In the first part of the work, the activity in water-gas shift reactions was evaluated for three Pt/Re/CeO2-based powder catalysts, with Pt/Re ratio equal to 1/1, 1/2 ad 2/1 and total loading approximate to 1 wt%. The catalysts were prepared by sequential dry impregnation of commercial ceria, with the salts precursors of rhenium and platinum; the activity tests were carried out by feeding a reacting mixture with a variable CO/H2O ratio, equal to 7/14, 7/20 and 7/24, and the kinetic parameters were determined. The model which better described the experimental results involves the water-gas shift (WGS) reaction and CO as well as CO(2)methanation. The preliminary tests showed that the catalyst with the Pt/Re ratio equal to 2/1 had the best performance, and this was selected for further investigations. In the second part of the work, a structured catalyst, obtained by coating a commercial aluminum alloy foam with the chosen catalytic formulation, was prepared and tested in different reaction conditions. The results demonstrated that a single stage water-gas shift process is achievable, obtaining a hydrogen production rate of 18.7 mmol/min at 685 K, at tau = 53 ms, by feeding a simulated reformate gas mixture (37.61 vol% H-2, 9.31 vol% CO2, 9.31 vol% CO, 42.19 vol% H2O, 1.37 vol% CH4).