Deciphering the interaction mechanism of components in bio-oil catalytic reforming for hydrogen production

Abstract

To elucidate the complex reaction mechanism of hydrogen production by catalytic reforming of bio-oil and reveal the interactions between the various components, this study selected four minimal model compounds (formic acid, methanol, acetone, and phenol) as typical representatives of acids, alcohols, ketones, and phenols, respectively, to avoid interference from multiple functional groups. Experiments were conducted using an in-situ gasification fixed-bed reactor (800 °C, WCR = 15, Ni/Al₂O₃ catalyst). The results show that methanol exhibits the best hydrogen production performance due to its high H/C ratio (4:1) and [-OH] with 75 mol% H₂ concentration and >97 % selectivity. When blended with formic acid, acetone, or phenol, methanol's hydrogen yield increased by 25 %, 8 %, 8 %, respectively. Formic acid-acetone mixtures enhanced H₂ concentration. However, [-C=O] promoted carbon chain elongation, resulting in fibrous carbon deposition and accelerated catalyst deactivation. Despite the presence of [-OH] in phenol, the stability of its aromatic ring structure limited reforming efficiency, yielding H₂ concentrations of 60–64 mol%. TG-DTG, SEM and FTIR analyses revealed that fibrous carbon deposition was predominantly driven by [-C=O], whereas [-OH] effectively suppressed carbon growth. This study elucidates the mechanistic role of bio-oil component interactions in hydrogen production, providing a theoretical foundation for optimizing catalyst design and feedstock formulations to advance sustainable hydrogen production from bio-oil.