Auto-thermal reforming of acetic acid for hydrogen production by ordered mesoporous Ni-xSm-Al-O catalysts: Effect of samarium promotion.

Biomass-derived acetic acid (HAc), as a hydrogen storage medium, can be transformed to hydrogen via on-board reformer for fuel cells. Steam reforming (SR) of HAc is a traditional hydrogen production process, but endothermicity of SR is a concern for heat management in dynamic on-board application. Auto-thermal reforming (ATR) of HAc is a promising route, while catalyst deactivation in harsh ATR atmosphere should be addressed. Samarium-promoted ordered mesoporous Ni-xSm-Al-O catalysts were synthesized via improved evaporation-induced self-assembly (EISA) method, and tested in ATR of HAc for hydrogen production. The Ni-2Sm-Al-O catalyst produced a stable HAc conversion near 100.0% and a hydrogen yield at 2.6 mol-H 2 /mol-HAc in a 30-h test. Meanwhile, the Ni-2Sm-Al-O catalyst shows resistance to oxidation, sintering and coking; this improved reactivity and durability can be attributed to basic Sm oxides and ordered mesoporous framework with confinement effect: the basic sites are beneficial to adsorption and activation of HAc, and the ordered mesoporous framework constrains the thermal agglutination of Ni metal and formation of coking, while intermediate carbonous species of *CH x (x = 0–3) can be gasified via the Sm 2 O 3 -Sm 2 O 2 CO 3 cycle. These Sm-promoted Ni-based catalysts are also tested with different temperatures and O/C, and show potentials in ATR of HAc for hydrogen production. Image 1 • Stable hydrogen production by auto-thermal reforming of acetic acid was achieved. • Conversion of CH 3 COOH at 100.0% and H 2 yield at 2.6 mol-H 2 /mol-HAc were obtained. • Ordered mesoporous Ni-xSm-Al-O synthesized by evaporation induced self-assembly. • Sm enhanced specific surface area and alkalinity of the Ni-xSm-Al-O catalysts. • Confinement effect by mesopores restrained coking and sintering of Ni0 species. [ABSTRACT FROM AUTHOR]