Current techniques of hydrogen production (primarily reformation of fossil fuels) are unsustainable, releasing CO₂ into the atmosphere, as well as consuming limited reserves of fossil fuels. The copper-chlorine cycle is a promising thermochemical process which can cost-effectively produce hydrogen with less environmental impact. In this thesis, new predictive formulations and experimental data are presented to improve the conversion extent and reaction rates of the hydrolysis reactor in the Cu-Cl cycle. This reactor has critical implications for the design, operation, and efficiency of the Cu-Cl cycle and hydrogen production. The relatively high temperature needed to drive the reaction requires a significant input of thermal energy. This thesis focuses on methods and analysis to reduce the unreacted steam in the hydrolysis reactor, in order to reduce the thermal energy input and improve the cycle’s thermal efficiency. A key outcome from this thesis is the experimental verification of reducing the steam to copper chloride ratio from 16:​1 (past studies) to about 3:​1. The results of this thesis provide key new data to design a more efficient hydrolysis reactor that can be effectively integrated within the Cu-Cl cycle.