A sintered Ni-YSZ catalytic reactor for highly efficient synthesis of green CH4

Abstract

Methane synthesis from CO₂ is an important process for transforming and storing renewable electrical energy, and one of the main issues facing methanation catalysts is stability. Herein, a plate-and-tube structured porous metal-ceramic Ni-YSZ reactor with high-temperature sintering was designed to produce CH₄ from CO₂ at atmospheric pressure and 325°C. The reactor was steadily operated for 1000 hours. The results showed that both the CO₂ conversion and the CH₄ selectivity continuously stayed over 90 % and 99.9 %, respectively. The results of in situ infrared and in situ programmed warming characterizations demonstrated that the hydrogenation of oxygen vacancies on the surface of Ni-O-Zr was the main pathway by which CO₂ was converted to CH₄ in this reactor. Moreover, the strongly basic adsorbed HCOO* and CO* intermediates facilitated further hydrogenation. This reactor structure decreases the reduction in reaction activity associated with catalyst sintering, coalescence, and carbon accumulation. Moreover, it provides a novel approach to reactor design for the stable operation of CO₂-derived methane at high temperatures.