(220d) Solar Hydrogen Production Via a Thermochemical FeSO4/FeO Water Splitting Cycle

The utilization of solar thermochemical water splitting cycles has been identified as one of the most favorable and viable options for producing hydrogen. Solar thermochemical water splitting cycles are a promising technology for sustainable hydrogen production. Among the various cycles, the sulfur-iodine cycle and its variant, the hybrid sulfur cycle, have garnered particular attention due to their lower operating temperatures compared to other thermochemical cycles. This characteristic renders them more feasible and economical for practical implementation. For both cycles, the most energy-intensive step is the dissociation of SO₃ into SO₂ and O₂, which is possible only under catalytic conditions. Observations have shown that noble metal catalysts can induce the endothermic dissociation of SO₃, even though sulfation poisoning remains a major concern in such reactions. While these types of reactions can benefit from the use of noble metal catalysts, these catalysts may not always be the top choice due to their high cost and limited availability. Our proposed solution to address the challenge at hand entails the utilization of a solar-driven water-splitting cycle based on metal oxide – metal sulfate (MO-MS) for hydrogen production. In this study, Bhosale and his team of researchers develop a thermodynamic model for the FeSO₄/FeO water splitting cycle. Computational thermodynamic analysis was carried out to estimate various process parameters by considering different temperatures, molar flow rates of inert sweep gas, and the inclusion of gas separators, heat exchangers, heaters, coolers, and fuel cell for determining the solar-to-fuel energy conversion efficiency.