Activity and stability performance of multifunctional catalyst (Ni/CaO and Ni/Ca12Al14O33[sbnd]CaO) for bio-hydrogen production from sorption enhanced biogas steam reforming.

Modified sorbents (NiO CaO and Ca 12 Al 14 O 33 CaO) were synthesized by hydration followed by wet mixing (HW) and tested in terms of their CO 2 sorption/desorption performance over multiple cycles. The results indicated the sorption capacities for Ni–CaO-HW and Al–CaO-HW decreased by only 3.8% and 6.4%, respectively, over 10 cycles. Various sequences of Ni 2+ loading onto modified CaO were investigated. The results indicated Ni–Al–CaO-HW to be the best performing exhibiting a pre-breakthrough time 30 min longer than the other samples. However, the H 2 purity and CH 4 conversion did not differ significantly amongst the various sorbents (approx. 94% purity H 2 and approx. 90% CH 4 conversion pre-breakthrough). The stability of the Ni–Al–CaO-HW was also investigated and the results indicated that the pre-breakthrough CH 4 conversion could be maintained at steady values for five cycles. However, the post-breakthrough CH 4 conversion decreases slightly over five cycles. A plausible explanation is that the formation of CaCO 3 results in the blockage of pores and active sites, which is supported by XPS results. [ABSTRACT FROM AUTHOR]