In-situ formed interface with Fe0 and Gaδ+-Ov in garnets boosting H2 production in chemical looping H2O splitting

It is of great significance but challenge to achieve superior H 2 O splitting performance by tailoring active sites in novel Fe-based mixed oxides in order to boost H 2 O activation to achieve the oxidation of metallic Fe to Fe 3+ back into parent substrate rather than thermodynamically more favourable Fe 2+ (Fe-O v ) usually exhibiting low H 2 O activation in chemical looping water splitting (CLWS). Herein, we for the first time reported the performance of Ga-doped garnets (Y 3 Fe 2 Ga x Al 3-x O 12 abbreviated as YF 2 G x Al 3-x , x = 1 and 2) for CLWS which surpassed most of the state-of-the-art Fe-based oxides by virtue of marvelous peak H 2 production rate of 195.3 mL min −1 g −1 , H 2 productivity of 60.7 mL g −1 , 100 % H 2 purity and outstanding redox stability for YF 2 G 2 A 1 . It was clarified that Ga doping led to the formation of an interface with Fe 0 and Ga δ+ -O v in garnets, which synergistically improved H 2 O dissociation, leading to the direct oxidation of Fe 0 to Fe 3+ back into garnets and thus accounting for its prominent performance.