title: The crucial role of the K+-aluminium oxide interaction in K+-promoted alumina- and hydrotalcite-based materials for CO2 sorption at high temperatures.
abstract: CO(2)-free hydrogen can be produced from coal gasification power plants by pre-combustion decarbonisation and carbon dioxide capture. Potassium carbonate promoted hydrotalcite-based and alumina-based materials are cheap and excellent materials for high-temperature (300-500 degrees C) adsorption of CO(2), and particularly promising in the sorption-enhanced water gas shift (SEWGS) reaction. Alkaline promotion significantly improves CO(2) reversible sorption capacity at 300-500 degrees C for both materials. Hydrotalcites and promoted hydrotalcites, promoted magnesium oxide and promoted gamma-alumina were investigated by in situ analytical methods (IR spectroscopy, sorption experiments, X-ray diffraction) to identify structural and surface rearrangements. All experimental results show that potassium ions actually strongly interact with aluminium oxide centres in the aluminium-containing materials. This study unambiguously shows that potassium promotion of aluminium oxide centres in hydrotalcite generates basic sites which reversibly adsorb CO(2) at 400 degrees C.
authors.affiliation: Hydrogen Production and Clean Fossil Fuels, Energy Research Centre of the Netherlands (ECN), Westerduinweg 3, Petten, The Netherlands. walspurger@ecn.nl
authors.forename: Stéphane
authors.initials: S
authors.lastname: Walspurger
authors.forename: Luciaan
authors.initials: L
authors.lastname: Boels
authors.forename: Paul D
authors.initials: PD
authors.lastname: Cobden
authors.forename: Gerard D
authors.initials: GD
authors.lastname: Elzinga
authors.forename: Wim G
authors.initials: WG
authors.lastname: Haije
authors.forename: Ruud W
authors.initials: RW
authors.lastname: van den Brink
mesh_terms: D000327:Adsorption; D000536:Aluminum Hydroxide / Q000737:chemistry*; D000537:Aluminum Oxide / Q000737:chemistry*; D002245:Carbon Dioxide / Q000737:chemistry*; D002254:Carbonates / Q000737:chemistry; D008276:Magnesium Hydroxide / Q000737:chemistry*; D011188:Potassium / Q000737:chemistry*; D013696:Temperature
chemical_list: D002254:Carbonates; D002245:Carbon Dioxide; C010467:hydrotalcite; D000536:Aluminum Hydroxide; D000537:Aluminum Oxide; D008276:Magnesium Hydroxide; D011188:Potassium