Low-temperature total oxidation of methane by pore- and vacancy-engineered NiO catalysts

Designing methane combustion catalysts operated under low temperature (<400°C) remains a huge challenge, especially for noble-metal–free catalytic systems. With NaCl as a crystalline scaffold, NiO catalyst with abundant oxygen vacancies and an ultra-high–specific surface area of 181 m 2 g −1 is obtained. The mesoporous NiO exhibits outstanding CH 4 combustion performance ( T 90 = 370°C at the weight hourly space velocity (WHSV) = 20,000 mL g −1 h −1 ). X-ray photoelectron spectroscopy (XPS), H 2 -temperature-programmed reduction (TPR), kinetic measurements, and O 18 isotope-labeling experiments together disclose the key role of surface lattice oxygen and reaction mechanism by NiO catalysts. More importantly, the excellent stability of NiO by doping La was obtained (low-temperature thermal stability: 385°C, 400 h, 4 vol% H 2 O).