Platinum catalyst supported on hydrotalcite for hydrogen production by aqueous-phase reforming of glycerol, glucose, glycine and humic acid

Wet biomass such as waste sludge in effluent treatment plants and microalgae can be effectively utilized by producing H-2-rich gases through aqueous-phase reforming (APR). Polyols, carbohydrates, proteins and humic substances are some classes of compounds present in such biofeeds. In this work, platinum catalyst was supported on hydrotalcite (HTlc) carrier and applied for APR of the respective model compounds, viz. glycerol, glucose, glycine and humic acid. H-2, CH4 and carbon oxides were the gaseous products. It was found that the catalyst performance varied when it was made differently. The 1% Pt/HTlc and 5% Pt/HTlc catalysts were characterized using X-ray diffraction, N-2-physisorption, scanning electron microscopy. The optimal catalyst, whose Pt content was 5 wt %, was characterized using electron microscopy and X-ray photoelectron spectroscopy techniques. Catalyst efficacy trials were performed between 215 and 245 degrees C using catalyst loadings (omega) between 2 and 6 kg/m(3). The initial concentration of all substrates was 1 wt %. The system pressure was equal to 3.9 MPa. The values of carbon conversion to gas phase (C-to-G conversion) after 3 h at T = 245 degrees C and omega = 6 kg/m(3) were so: glycerol-37.3, glucose-26.7 and glycine-15.6%. The respective values of H-2 yield (Y-H-2) were: glycerol-22.8, glucose-14.7 and glycine-5.4%. The values of Y-H-2 were very low for the reaction with humic acid. The results of this model compound study will provide useful insight into APR of wet biofeeds.