Canadian advances in the copper–chlorine thermochemical cycle for clean hydrogen production: A focus on electrolysis

Thermochemical looping technologies for clean hydrogen production – Current status and recent advances

“…High mechanical strength and thermal stability of the cell have been achieved by utilizing polybenzimidazole (PBI) based membranes modified with zirconium phosphate (ZrP) (Kamaroddin et al, 2019). A three-electrode half-cell and single-cell study have been recently conducted at CNL, and the effects of CuCl concentration, temperature, current density, and flow rate have been investigated (Li et al, 2020). It is depicted that a 50 L/h hydrogen production is achieved at the current density of around 0.4 A/cm 2 at 353 K with 2M CuCl solution accomplished with a dynamically responsive and robust operation.…”

Studies on Reaction Products, Byproducts, and Intermediates in Thermal Steps of the Cu–Cl Thermochemical Cycle for Hydrogen Generation

“…The maximum operation temperature of the Cu–Cl thermochemical cycle ( T max = 530 °C) is much lower as compared to sulfur-based cycles ( T max = 850 °C), thus offering advantages in the selection of materials of construction, and also enhances the practicability for the Cu–Cl process to be coupled with a solar energy source . A four-step Cu–Cl cycle has been widely accepted and studied by several institutes globally; the prominent are the Canadian Nuclear Laboratories (CNL) and University of Ontario Institute of Technology (UOIT) in Canada. , All four steps of the Cu–Cl cycle and chemical reactions involved are shown in Figure . In spite of the advantages, the Cu–Cl cycle encounters few challenges in each step, which needs to be addressed for efficient and economical hydrogen production.…”

“…In spite of the advantages, the Cu–Cl cycle encounters few challenges in each step, which needs to be addressed for efficient and economical hydrogen production. First, in the electrochemical step, copper crossover takes place across the membrane during CuCl/HCl electrolysis, which lowers the efficiency of the electrolyzer; another hindrance is incomplete recovery of the spent electrolyte from the anolyte . Water as a reactant enters into the hydrolysis step of the Cu–Cl cycle followed by the decomposition step.…”

“…18 A four-step Cu−Cl cycle has been widely accepted and studied by several institutes globally; the prominent are the Canadian Nuclear Laboratories (CNL) and University of Ontario Institute of Technology (UOIT) in Canada. 18,19 All four steps of the Cu−Cl cycle and chemical reactions involved are shown in Figure 1. In spite of the advantages, the Cu−Cl cycle encounters few challenges in each step, which needs to be addressed for efficient and economical hydrogen production.…”

“…First, in the electrochemical step, copper crossover takes place across the membrane during CuCl/HCl electrolysis, which lowers the efficiency of the electrolyzer; another hindrance is incomplete recovery of the spent electrolyte from the anolyte. 19 Water as a reactant enters into the hydrolysis step of the Cu−Cl cycle followed by the decomposition step. In the hydrolysis step, the side reaction of CuCl 2 thermolysis to CuCl and requirement of a high steam/ copper ratio are main challenges and were addressed using a fixed-bed reactor in our earlier publication.…”