Understanding oxygen carrier-support interactions in looping hydrogen production

Chemical looping hydrogen production (CLHP) offers a promising route for continuous high-purity H 2 generation with integrated carbon capture. Fe 2 O 3 is a commonly used oxygen carrier (OC) in CLHP but is limited by moderate reactivity and low stability. Employing ionic conductor as OC support has been proposed to overcome these limitations, yet the underlying mechanisms, particularly the OC-support interactions, remain unclear. Here, we investigated CaTiO 3 as a model support and Al 2 O 3 as a reference to elucidate the origins of enhanced performances. The CaTiO 3 -Fe 2 O 3 composite exhibited a substantially high reduction rate (~4 times), significantly increased H 2 yield (50% ~ 280%), and enhanced stability over multi redox cycles compared to the reference, comparable to Fe 2 O 3 supported on well-established ionic conductors. The improved performance is ascribed to increased oxide ion mobility within the bulk Fe 2 O 3 . DFT calculations revealed that the oxide ion mobility was synergistically driven by low-concentration Ti doping and CaTiO 3 induced tensile strain.