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Kinetic and electrochemical analyses of a CuCI/HCl electrolyzer
Author(s) -
Soltani Reza,
Dincer Ibrahim,
Rosen Marc A.
Publication year - 2019
Publication title -
international journal of energy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.808
H-Index - 95
eISSN - 1099-114X
pISSN - 0363-907X
DOI - 10.1002/er.4703
Subject(s) - overpotential , electrolysis , anode , electrochemistry , cathode , chemistry , inorganic chemistry , electrolysis of water , current density , electrochemical cell , analytical chemistry (journal) , electrode , organic chemistry , physics , electrolyte , quantum mechanics
Summary An electrochemical analysis is carried out from a kinetic electrochemistry perspective of a CuCl/HCl electrolysis cell, within the CuCl thermochemical water splitting process for hydrogen production. The anolyte is a solution of 2 mol L −1 CuCl(aq) and 10 mol L −1 HCl(aq) while the catholyte solution is 11 mol L −1 HCl(aq) . The cell current density of 0.5 A cm −2 and voltage of 0.7 V are the desired working conditions for a CuCl/HCl electrolyzer. The current density of 0.5 A cm −2 is assumed to occur at a 5% anolyte conversion degree. At 25 °C , the activation overpotential of the anode half‐reaction is found to be 53 mV for a current density of 0.5 A cm −2 while the activation overpotential of the cathode half‐reaction for the same condition is 87 mV. An increase in working temperature decreases the overpotential of the anode half‐reaction and increases the cathode half‐reaction activation overpotential. The ohmic overpotential of the cell membrane is almost 1000 times smaller than that of the activation overpotentials of the electrode half‐reactions for the same temperature and current density. A higher working temperature results in a lower membrane ohmic overpotential. The required voltage to trigger electrolysis for a current density of 0.5 A cm −2 is found to be 0.53 V at 25 °C and 0.59 V at 80 °C and a higher temperature results in a higher electrochemical efficiency. The cell electrochemical efficiency increases linearly with working temperature while the voltage efficiency peaks at 75% at 60 °C .