Solid solution-type Sm–Pr–O supported nickel-based catalysts for auto-thermal reforming of acetic acid: the role of Pr in solid solution

Abstract

Hydrogen, as a promising energy carrier, can be extracted from renewable biomass derived acetic acid (HAc). Ni-based catalysts supported on solid solution of Sm_2−xPr_xO_3±δ were prepared using a coprecipitation method and evaluated in auto-thermal reforming (ATR) of HAc for hydrogen production. The results revealed that Pr species infiltrated the Sm₂O₃ lattice and formed a solid solution structure with oxygen vacancy defects, in which the redox process of Sm³⁺ + Pr³⁺ ⇌ Sm²⁺ + Pr⁴⁺ enhanced oxygen mobility, facilitating gasification of the coking precursor and suppressing carbon deposition. DFT analysis also confirmed that Pr doping into the Sm_2−xPr_xO_3±δ solid solution significantly lowered the energy barrier by 112 kJ mol⁻¹ for formation of oxygen vacancies. Additionally, the interaction between Ni⁰ and Sm_2−xPr_xO_3±δ effectively improved the dispersion of Ni⁰ metal particles, inhibiting sintering of Ni species. Consequently, the NSP10 catalyst (Ni_0.80Sm_1.72Pr_0.24O_3.74±δ) exhibited outstanding catalytic performance for hydrogen production: the conversion of HAc approached 100%, while the hydrogen yield remained stable at 2.75 mol-H₂/mol-HAc.