CeO2-ZrO2 nanocomposite-stabilized Ni/CaO bifunctional material: Novel candidate for sustainable hydrogen production via SESR of bio-oil

• CeO2-ZrO2 nanocomposite (CZ)-stabilized Ni/CaO bifunctional material (BFM) was developed • BFM was applied in intensified sorption-enhanced bio-oil steam reforming (SESRBO) • Incorporation of CZ improved the cyclic stability of CaO-based sorbent • Max H2 purity of 94% was achieved during the 1st cycle SESRBO and lasted for 33 min • Ni/(CaO-20CZ) BFM exhibited high stability over 10 SESRBO cyclic operations A well-designated CeO 2 -ZrO 2 nanocomposite (CZ) was successfully synthesized using a hydrothermal approach. For the first time, CZ was examined as i) supporting material for Ni catalyst (Ni-CZ) during steam reforming of bio-oil (SRBO) and ii) stabilizing material for Ni/CaO catalyst/sorbent bifunctional material (Ni/(CaO-xCZ)) during the intensified sorption-enhanced SRBO (SESRBO) process. The impact of CZ wt.% (x: ranging from 0% to 25%) and mixing pattern (mechanical mixture and bifunctional material (BFM)) on sorption capacity and stability were evaluated over 15 carbonation/calcination cycles. All CZ-stabilized CaO (CaO-xCZ) materials, especially CaO-20CZ, demonstrated high cyclic stability due to the generation of CaZrO 3 perovskite structure that serves as a barrier against CaO sintering. Compared to mechanical mixing pattern (Ni-CZ (catalyst) + CaO (sorbent)), Ni/(CaO-20CZ) displayed 27% higher CaO conversion at 15 th carbonation cycle. At 600°C and steam-to-carbon (S/C) ratio of 3, bio-oil conversion of 96.2% and H 2 yield of 75.8% were achieved over Ni-CZ catalyst during SRBO reaction. Furthermore, Ni/(CaO-20CZ) BFM led to a hydrogen purity of approximately 94% during the pre-breakthrough period (maximum intensified period), sustained for 33 min. Ni/(CaO-20CZ) also maintained a high cyclic stability without noticeable decline in terms of H 2 purity and yield over 10 consecutive SESRBO cycles.