Highly efficient methane decomposition to H2 and CO2 reduction to CO via redox looping of Ca2FexAl2-xO5 supported NiyFe3-yO4 nanoparticles

Abstract

Catalytic methane decomposition (CMD) due to its various potentials including production of COx free H2 and technically simpleness, but is very challenging due to the lack of efficient, stable, and carbon-separable catalysts. An innovative chemical looping methane decomposition with CO2 reduction (CLMDCR) was developed to bridge the gap via the reduction → CMD → oxidation looping of a catalytic oxygen carrier (COC) for H2 production, deposited carbon separation, and CO2 reduction to CO. As high as 96.3 vol.% and 95.2 vol.% purities of H2 and CO can be generated using the COC (NiyFe3-yO4-Ca2FexAl2-xO5), superior to those obtained with state-of-the-art CH4 dry reforming. The COC shows not only high activities but also remarkable durability as demonstrated with 20 cyclic CLMDCR tests. Experimental results indicate that the long-term redox durability of COC is attributed to its atomic homogenization through the phase transformations of NiyFe3-yO4 ↔ Ni-Fe and Ca2Fe1.52Al0.48O5 ↔ CaO + Fe + Ca2FexAl2-xO5.