Aqueous-phase reforming of methanol, acetic acid, 4-methylcatechol, and phenol over supported nickel and platinum catalysts

The aqueous phase reforming of methanol, acetic acid, phenol, and 4-methylcatechol was studied to evaluate the potential of using process water from hydrothermal liquefaction of black liquor for hydrogen production. Various catalysts, including Cu- or Co-doped nickel and commercial Pt/AC, were tested under plug-flow conditions (230 °C, 32 bar). The platinum catalyst showed superior stability, maintaining high conversion with methanol and acetic acid. However, it showed no activity with phenol and deactivated rapidly when exposed to 4-methylcatechol. Doped nickel catalysts experienced severe deactivation, particularly with acetic acid and phenolic compounds. While nickel catalyst deactivated in the presence of acetic acid, Pt showed stable conversion but favored decarboxylation reaction. APR of methanol primarily produced H₂ and CO₂, with NiCu/γ-Al₂O₃ being the most selective for H₂. Co-doped nickel favored hydrogenation, forming CH₄ and thus reducing H₂ yield. APR of phenol and 4-methylcatechol produced H₂, CO₂, and hydrodeoxygenated or hydrogenated liquid products.