Advances in Heterogeneous Catalysis for Hydrogen Production via Steam Reforming of Biomass-Derived Alcohols: Catalytic Structure-Activity Relationships from Ethanol to Glycerol Systems

• • Ni-based catalysts, often alloyed with Fe, Co, or Cu, achieve high C–C bond activation for ethanol steam reforming, but require rare-earth oxide promoters (Ce, Pr, La) to maintain stability against coking; for instance, Ni–Co/MgAl2O4 systems demonstrate stable operation at temperatures around 600–700°C, with hydrogen yields exceeding 70% and minimal deactivation over 100 h on stream. • • Noble metal catalysts (Pt, Rh, Ir) offer superior low-temperature activity (e.g., complete ethanol conversion below 400°C) but are cost-prohibitive; recent strategies employ single-atom Rh on high-index CeO2 facets, achieving turnover frequencies up to 0.5 s−1 at 150°C for CO oxidation, indicating potential for low-temperature reforming. • • Glycerol steam reforming suffers from severe coking due to its trihydroxy structure; catalysts such as promoted Co/MgO with rare-earth additives (La, Ce) exhibit improved coke resistance, maintaining >80% glycerol conversion and >60% H2 selectivity for 50 h at 650°C, whereas unpromoted catalysts deactivate within 10 h. • • The review emphasizes that catalyst design must be tailored to the specific alcohol: ethanol requires suppression of dehydration and methanation, ethylene glycol benefits from enhanced C–C cleavage, and glycerol demands robust coke resistance; this is achieved by tuning metal-support interactions and oxygen mobility, as demonstrated by Ni–Cu/SiO2 catalysts that reduce methanation selectivity by 30% compared to monometallic Ni.