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A Stand‐Alone Module for Solar‐Driven H 2 Production Coupled with Redox‐Mediated Sulfide Remediation
Author(s) -
Obata Keisuke,
Shinohara Yuuki,
Tanabe Shinichi,
Waki Ichitaro,
Kotsovos Konstantinos,
Ohkawa Kazuhiro,
Takanabe Kazuhiro
Publication year - 2019
Publication title -
energy technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.91
H-Index - 44
eISSN - 2194-4296
pISSN - 2194-4288
DOI - 10.1002/ente.201900575
Subject(s) - redox , electrochemistry , sulfide , chemistry , cathode , anode , chemical engineering , inorganic chemistry , materials science , electrode , organic chemistry , engineering
Efficient electrochemical devices are required to convert electric power by intermittent renewable energy sources into a chemical form. The choice of combination in reduction–oxidation reactions can vary depending on the target, which provides different thermodynamics and kinetics. A promising approach for H 2 production coupled with sulfide remediation is demonstrated to utilize the intermediate redox media. H 2 is produced on the cathode, and soluble redox ions in a reduced form are oxidized on the anode. The ions are then transferred to a separate reactor to oxidize the sulfide ions via a homogeneous reaction, and the reduced redox ions are recirculated. A solar‐driven redox photovoltaic‐electrochemical (PV‐EC) system is operated as a stand‐alone module and is composed of Cu(In,Ga)(S,Se) 2 (CIGS) PVs and EC cells in series and operated under natural solar irradiation. A unique EC cell is established in an aqueous‐phase membraneless configuration at ambient temperature, and a cathode is decorated with a semipermeable CrO x ‐based nanomembrane. This allows for selective H 2 evolution without causing Fe redox reduction. Remaining issues associated with the stability of the CrO x permselective layer on the cathode are also discussed, which are associated with the formation constant of a soluble metal complex in the presence of ligand counterions.