Modulating lattice distortion of NiO/MgAl_2-<i>x</i>Fe_<i>x</i>O₄ for low-temperature methane decomposition with CO₂ reduction

Abstract

Methane decomposition technology is regarded as a promising pathway for one-step H₂ generation but suppressed by carbon deposition and catalyst deactivation. To solve these problems, a series of NiO/MgAl_2-xFe_xO₄ (0.50 ≤ x ≤ 2.00) catalysts were prepared for accomplishing low-temperature H₂ generation from catalytic methane dissociation and alleviating catalyst invalidation through a carbon dioxide reduction strategy. Results indicate that a methane conversion of 91.03% and a hydrogen concentration of 91.21 vol% were achieved at 650 °C using NiO/MgAlFeO₄. Long-term durability experiments were conducted under high-temperature and carbon-deposited conditions, and the NiO/MgAlFeO₄ material still had highly satisfactory activity and stability after 20 cycles. It is revealed that the lattice distortions of Fe-O and Al-O in NiO/MgAl_2-xFe_xO₄ could be the dominant factor for boosted hydrogen generation from methane decomposition, synergistically promoting methane activation and dehydrogenation. These findings provide new implications for advanced catalyst design, which will substantially promote methane decomposition in a highly efficient manner.