Hydrogen Production by Aqueous-Phase Reforming of Model Compounds of Wet Biomass over Platinum Catalysts

This work describes hydrogen production by the catalytic aqueous-phase reforming of model compounds of microalgae and activated sludge over Pt/Al2O3 and Pt/Al2O3–CeO2 catalysts in a batch reactor. Glycerol, glucose, alanine, and humic acid were the chosen model compounds. They represented polyols, carbohydrates, amino acids, and humic substances in wet biomass. Both catalysts were characterized using nitrogen adsorption–desorption, scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy techniques. Process parameters such as reforming temperature, batch time, and catalyst loadings were varied using 1 wt % feed solutions of the compounds to identify the best reaction conditions (T = 245 °C, P = 3.5 MPa, and t = 3 h). The constituents of the gaseous product were H2, CH4, CO2, and CO. Carbon-to-gas phase conversions for reforming of glycerol, glucose, and alanine over Pt/Al2O3 were 66, 18.1, and 12.5%. The respective H2 yields were 12.2, 11.8, and 8%. When the Pt/CeO2–Al2O3 catalyst was used, conversion values changed to 45, 18, and 20%, while the respective H2 yields were 9.5, 10.9, and 8.7%. Humic acid, which is a constituent of sewage sludge, exhibited a low tendency to H2 production. In this way, a candidate option for the production of H2-containing gaseous product (with high heating value) from wet biomass was investigated. These findings will improve the technology for the production of sustainable advanced biofuels from aqueous biomass streams.