Accelerated Oxygen Dual Activation and Acetic Acid Activation for Hydrogen Production via Autothermal Reforming of Acetic Acid

Catalytic conversion of the biomass-derived secondary product, namely, autothermal reforming of acetic acid (HAc), into hydrogen offers a potential route to alleviate current energy problems. Hitherto, the precise activation of oxygen species, including lattice O^2– and molecular O₂, has not been achieved, which restrains the oxygen catalytic cycle and carbon precursor gasification. Herein, Sm–Ce–O solid solution (SC)-supported dual-site Ni (single atom (SA) + nanoparticle (NP)) catalysts were obtained. The redox couples of Sm²⁺/Sm³⁺ and Ce³⁺/Ce⁴⁺ induced support lattice distortion, which facilitated lattice O^2– activation. Simultaneously, the abundant oxygen vacancies near the nickel single atom sites accelerated the chemisorption and activation of molecular O₂. Furthermore, the constructed Ni_SA-SC interface promoted migration of subsurface lattice O^2– to the surface, which in turn was supplemented by molecular O₂. Although with higher oxygen activation ability, the poor reactivity in adsorption and C–C bond breaking of CH₃CO* for the Ni_SA-SC interface led to undesirable HAc conversion, which could be improved by introducing the Ni_NP-SC interface. Consequently, with the Ni_SA-SC interface and solid solution activated molecular O₂ and lattice O^2–, respectively, and the Ni_NP-SC interface promoted HAc conversion, the optimal Ni_0.32Sm_0.88Ce_0.12O_1.88 ±δ catalyst with dual-site Ni ran for 10 h without deactivation and exhibited a high hydrogen yield of 2.6 mol-H₂/mol-HAc.