One dimensional nano-fiber structured Fe2O3/ZrO2 to enable efficient hydrogen production via water gas shift with chemical looping

Chemical looping provides a novel route to enable efficient hydrogen generation but is limited by lacking highly active and stable oxygen carriers. Here, we proposed the one-dimensional nano-fiber Fe2O3/ZrO2 for chemical looping water gas shift to produce hydrogen and studied the size effect on the redox chemistry. The results show that the reactivity and stability of nano-fibers is size dependent. Increasing the size can significantly strengthen the stability albeit reducing the activity. In particular, the nano-fiber with the diameter of similar to 99 nm shows both high hydrogen yield (9.07 mmol.g(-1)) and stable performance over 60 redox cycles at 750 degrees C. Mechanism study manifests that the small size can enhance the reduction depth in the initial few cycles, leading to high hydrogen production, but at the expense of severe sintering after repetitive cycles. Therefore, the selection of an optimal size (99 nm in diameter) is key to simultaneously ensure high reactivity and stability. We anticipate that the size effect on the redox chemistry will have extensive implications for the development of efficient oxygen carriers.

Automated summary

In this study, one-dimensional nano-fiber Fe2O3/ZrO2 was used as a catalyst for chemical looping water gas shift to produce hydrogen, and the effect of particle size on the redox chemistry was studied. The results showed that the reactivity and stability of nano-fibers were size dependent. Increasing the particle size significantly enhanced stability but reduced activity. Particularly, the nano-fiber with a diameter of about 99 nm exhibited high hydrogen yield and stable performance over 60 redox cycles at 750 degrees C. Mechanism study revealed that the small size could enhance reduction depth in the initial cycles for high hydrogen production, but caused severe sintering after repetitive cycles. Therefore, selecting an optimal size (99 nm in diameter) is crucial for simultaneously ensuring high reactivity and stability. We anticipate that the size effect on redox chemistry will have extensive implications for the development of efficient oxygen carriers.