Aqueous phase reforming of xylitol and sorbitol over Pt/Al2O3 catalysts: Effect of Pt content on hydrogen production

HERNAN DUARTE; MARÍA EUGENIA SAD; CARLOS RODOLFO APESTEGUÍA

Pittsburgh

Congreso; 24 NAM (North American Meeting); 2015

ACS

Aqueous-phase reforming (APR) was proposed as a catalytic approach to produce H2 and/or alkanes from biomass-derived oxygenates [1]. In order to favor H2 production, the catalyst used must promote the cleavage of C?C, O-H, and C-H bonds in the oxygenated reactant (leading to H2, CO and CO2), and facilitate the water-gas shift (WGS), as opposed to the cleavage of C?O bonds (leading to alkanes). Pt/Al2O3 has been proved to be active and selective for APR due to its capability to break C?C bond and suitability to catalyze the WGS reaction. The APR process is very complex and many side reactions may also occurred over bifunctional catalysts as it is shown in Scheme 1 for xylitol APR. APR of ethylene glycol, glycerol and even sorbitol was widely studied [1] and few papers deals with C5 sugars, which are founded in lignocellulose biomass and are difficult to be used in biological fermentation process [2]. Even little work has been carried out so far to optimize the metal content in the catalysts. Therefore, we study in this work the effect of Pt loading when using Pt/Al2O3 over the selective production of H2 via APR reaction from xylitol and sorbitol. We study the effect of metal loading when using Pt/Al2O3 catalyst over H2 production via xylitol and sorbitol APR. When Pt content increases, the selective formation of gas-phase products also increases. However, similar H2 yield (54%) was achieved when using 1.5 or 2.77 % Pt/Al2O3 for xylitol APR showing that there is not necessary to impregnate with an excess of Pt as usually reported in literature for APR reaction.