An intelligent oxygen carrier of La2−xSrxNiO4−λ for hydrogen production by chemical looping reforming of ethanol

This work studied an intelligent perovskite of La2−xSrxNiO4−λ as oxygen carrier (OC) to produce hydrogen in chemical looping reforming (CLR) process. It was prepared by co-precipitation method and investigated by XRD, TEM, ICP-OES, H2-TPR, TGA technologies and fixed-bed experiment. The 'intelligence' refers to the self-regeneration ability and structural flexibility of perovskite. The former was verified by the movement that Ni ions repeatedly immerse into and out of perovskite bulk during CLR process. The movement suppressed the growth of Ni particles and maintained its high dispersion. The latter was confirmed by the addition of promoters. The insertion of Sr increased lattice oxygen mobility and greatly strengthened the reversible evolution of metallic Ni, which boosted the carbon-resistance and hold favorable stability of OC. The La1.4Sr0.6NiO4−λ was the optimized composition owing to the superior activity, higher hydrogen selectivity (87%) and admirable stability. Moreover, shortened 'dead time' and more ideal self-regeneration property of perovskite were attained due to easier reducibility of Ni ions.