Mn-doped NiTiO₃ catalysts for hydrogen production via auto-thermal reforming of acetic acid

Auto-thermal reforming (ATR) of acetic acid (HAc) offers a feasible, carbon-neutral way to produce hydrogen, and Ni-based catalysts were found effective in ATR, while catalytic deactivation by sintering and carbon deposition needs to be addressed. Therefore, novel Mn-doped NiTiO3 catalysts were prepared by evaporation induced self-assembly method and tested in ATR; characterizations were used to explore the internal catalytic relationship between the carrier and active metals. The experimental results indicated the NiTiO3 catalyst doped with 10 wt.% of MnO exhibited the highest activity and enhanced stability: the conversion of HAc was stable at 100% and the yield of hydrogen was recorded near 2.5 mol-H2/mol-HAc. The characterization results showed that the NiTiO3 catalyst presented the highest specific surface area at 7.5 m2/g. After reduction and activation, NiTiO3 was transformed into Ni0, while Mn replaced Ni in NiTiO3 and formed a stable phase of MnTiO3 perovskite, which presented confinement effect on Ni0, preventing migration of Ni0 at high temperature with a relatively stable particle size within 41.6-44.5nm. These MnTiO3-supported nickel species effectively promoted the conversion of intermediate products such as CH3CO*, inhibited carbon deposition and improved hydrogen selectivity, showing application potential for hydrogen production via ATR of HAc.