Influence of physicochemical properties on the thermochemical water splitting performance and H2 production of CoFe2O4

This research investigates the impact of physicochemical properties on the thermochemical redox ability of CoFe2O4 for water splitting application. Three samples with different properties (CFO-A, CFO-B, and CFO-C) are evaluated. The results reveal that particle size, Co/Fe ratio, and the spinel inversion degree notably affect the redox behavior and sintering of the material. The sample with the smallest particle size (CFO-A, 14 nm) exhibits the most pronounced sintering and the lowest redox performance. Meanwhile, the H2 production results show the effect of the Co/Fe ratio and spinel inversion. The sample with Co/Fe = 0.5 (CFO-B), exhibits the highest H2 production (595 mu mol g-1), compared to the samples with Co/Fe = 0.6 (CFO-A and CFO-C). Thermodynamic calculations support these findings, suggesting that the thermochemical water splitting reaction is thermodynamically more favorable with a Co/Fe ratio = 0.5. The spinel inversion degree also influences the performance of the material, since CFO-B, the most efficient sample, shows the lowest inversion degree (67 %), compared to CFO-A and CFO-C (70 and 68 %). These results stress the importance of thoroughly controlling the physicochemical properties of the active redox material.