Fuel-cell grade hydrogen production by coupling steam reforming of ethanol and carbon monoxide removal

The integration of H2 production and purification is an essential step in the development of sustainable power generation in proton exchange membrane fuel cells. Thence, coupling of steam reforming of ethanol (SRE) and carbon monoxide removal was evaluated for further hydrogen production in fuel cells. Firstly, SRE on RhPt/CeO2-SiO2 catalyst was carried out at 700 °C, displaying a stable product distribution for 120 h. Then, CO removal from the actual post-reforming stream was evaluated over several AuCu/CeO2 catalysts with different Au:Cu weight ratios (1:0, 3:1, 1:1, 1:3, and 0:1). The role of each active metal was identified: Au favors CO conversion by the formation of carbon intermediates, and Cu improves CO2 selectivity due to its redox properties. A 1:1 Au:Cu weight ratio on the AuCu/CeO2 catalyst at 210 °C favors complete CO removal from the post-reforming stream, achieving fuel-cell grade hydrogen production. However, 25% of H2 was loss during the CO removal step, which is very high compared to studies with synthetic feeds. These high H2 loss would be the result of a complex network of reactions occurring during the real post-reforming cleaning. Characterization tests allowed us to identify that CeO2, combined with the Cu redox properties, favors water decomposition and CO conversion. Likewise, catalyst reduction might favor Au-Cu alloy formation due to the similar crystal lattice. Finally, stability tests showed that Au1.0Cu1.0/CeO2 catalyst is susceptible to rearrangement due to the cumulative oxidation of its surface during operation. Nonetheless, periodic in-situ reduction treatment contributes to the Au-Cu alloy formation and stabilization, maintaining high activity and mitigating H2 loss. Indeed, Au1.0Cu1.0/CeO2 catalyst was active for 95 h when reduced every 24 h, achieving fuel-cell grade hydrogen with a minimum of 14% H2 loss.

• Autores: Cifuentes Vanegas, Bernay; Bustamante Londoño, Felipe; Conesa, Juan A.; Cobo Ángel, Martha Isabel; Córdoba Castrillón, Luis Fernando
• Tipo de recurso: Article of investigation
• Fecha de publicación: 2018
• Institución: Universidad de Antioquia
• Repositorio: Repositorio UdeA
• Idioma: eng
• OAI Identifier: oai:bibliotecadigital.udea.edu.co:10495/46201
• Acceso en línea: https://hdl.handle.net/10495/46201
• Palabra clave: Óxidos metálicos; Reacciones de hidrogenación; Catalizadores bimetálicos; Reacciones químicas; Producción de energía; Tecnología del hidrógeno; 2. Ingeniería y Tecnología; Bimetallic catalysts; Ceria; CO-PROX; Methanation; Water gas shift reaction; ODS 7: Energía asequible y no contaminante. Garantizar el acceso a una energía asequible, fiable, sostenible y moderna para todos
• Rights: openAccess
• License: CC BY-NC-ND