CuCl/HCl Electrolyzer Kinetics for Hydrogen Production Via Cu-Cl Thermochemical Cycle

Abstract

An investigation of kinetic properties of the CuCl/HCl electrolytic cell verified methods applied in this study to significantly reduce the catalyst loadings required to achieve a current density of 0.5 A/cm2 at 0.7 V. The CuCl/HCl electrolytic cell is a key component of the Cu-Cl thermochemical cycle. The economic viability of the Cu-Cl thermochemical cycle was significantly improved by reducing the platinum loading required to achieve higher current densities. Electrochemical impedance spectroscopy (EIS) and linear sweep voltammetry (LSV) were employed to investigate overpotentials of the individual electrodes and the electrolytic cell. A laboratory scale CuCl/HCl electrolytic cell was used to verify that the catalyst loading could be reduced by 68 % and still maintain a current density of 0.5 A/cm2 at 0.7 V.

Thermodynamics and Efficiency of a CuCl(aq)/HCl(aq) Electrolyzer

“…In previous research [2], copper deposition at the cathode from copper permeation through the membrane was a significant obstacle. However, recent studies have since demonstrated that the obstacle can be overcome by increasing the concentration of HCl(aq) at the cathode [3,[14][15][16]. When copper deposition is not occurring, the current efficiency measurements of hydrogen production in the electrolytic cell have consistently been greater than 90 %.…”

Kinetic and electrochemical analyses of a CuCI/HCl electrolyzer

“…Canada Nuclear Laboratories (formerly Atomic Energy of Canada Limited) demonstrated hydrogen production by a CuCl electrolyzer continuously for several days and reported that electrolysis is feasible at low potentials (0.6‐0.7 V) at a current density of 0.1 A cm −2 using inexpensive materials . The Pennsylvania State University has carried out comprehensive experiments and theoretical developments on the cycle . Balashov et al performed an experimental study on a CuCl/HCl electrolyzer and reported a voltage efficiency of 80% and a current efficiency of 98%, which is with a good agreement with Faraday law.…”

“…Balashov et al performed an experimental study on a CuCl/HCl electrolyzer and reported a voltage efficiency of 80% and a current efficiency of 98%, which is with a good agreement with Faraday law. Hall et al experimentally investigated the activation overpotentials of anode and cathode half‐reactions as well as full‐cell overpotentials and concluded that the magnitude of the overpotential is higher for the cathode half‐reaction than the anode half‐reaction. The overall cell's overpotential to trigger hydrogen production was 0.55 V .…”

“…The overall cell's overpotential to trigger hydrogen production was 0.55 V . Also, by applying precise Pt loading on the cathode, Hall et al were able to reduce the required catalyst amount by 68% while maintaining the same performance. In another study, the CuCl/HCl electrolysis efficiency was found to be 20% for a current density of 0.5 A cm −2 , while the electrolyzer efficiency decreased with rising current density.…”

“…Hall et al 22 experimentally investigated the activation overpotentials of anode and cathode half-reactions as well as full-cell overpotentials and concluded that the magnitude of the overpotential is higher for the cathode half-reaction than the anode half-reaction. The overall cell's overpotential to trigger hydrogen production was 0.55 V. 22 Also, by applying precise Pt loading on the cathode, Hall et al 22 were able to reduce the required catalyst amount by 68% while maintaining the same performance. In another study, 23 the CuCl/HCl electrolysis efficiency was found to be 20% for a current density of 0.5 A cm −2 , while the electrolyzer efficiency decreased with rising current density.…”