Ethanol Steam Reforming over cobalt catalysts: operando XANES and NAP-XPS studies

CRISTIÁN HUCK IRIART; ALBERT CASANOVAS; LLUIS SOLER; CARLO MARINI; JORDI PRAT; JORDI LLORCA PIQUÉ; CARLOS ESCUDERO

Shanghai

Workshop; The 4th Annual Workshop on Ambient Pressure X-ray Photoelectron Spectroscopy; 2017

The Ethanol Steam Reforming (ESR) reactionis a well-known process used for hydrogen generation and especially interestingfor the on-site production of this gas. Three different Co-based catalysts havebeen studied for the ESR reaction using operandoNear Ambient Pressure XPS (NAP-XPS) and X-ray Absorption Near Edge Structure(XANES) at the ALBA Synchrotron Light Source. The Co-based catalysts studied wereCo3O4 (Co-spinel), Co3[Si2O5]2(OH)2(Co- talc) and  [Co2Mg4Al2(OH)16]CO3·4H2O(Co-hydrotalcite or Co-HT). The use of Cobalt-based catalysts allows decreasingthe reaction temperature since there is no methane generation in theintermediate reaction steps as opposed to other catalysts that do produce thisgas, which can only be reformed at high temperature. Furthermore, the possibilityto operate at lower temperatures shifts the WGS reaction balance towards theformation of hydrogen. However, Co-based catalysts can be deactivated under ESRreaction conditions due to carbon deposition and this fact has been attributed tothe formation of metallic Co[1]. Our results show that whenusing Co-spinel and Co-talc for ESR metallic Co is detected while for Co-HT,which exhibits an excellence performance for ESR, there is no formation ofmetallic Co. This interesting result allows designing cobalt-based catalystsfor ESR without coke deposition by placing in appropriate environments Coδ+active species.