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Structures Self‐Assembled from Anionic Graphene and Cationic Manganese Porphyrin: Characterization and Application in Artificial Photosynthesis
Author(s) -
Kaplan Amir,
Korin Eli,
Bettelheim Armand
Publication year - 2014
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201400054
Subject(s) - chemistry , porphyrin , graphene , oxide , intercalation (chemistry) , inorganic chemistry , x ray photoelectron spectroscopy , cyclic voltammetry , cationic polymerization , electrochemistry , electrode , photochemistry , chemical engineering , organic chemistry , engineering
Carboxylic‐rich graphene oxide (CGO) and Mn III tetrakis( N ‐methyl‐4‐pyridinio)porphyrin (MnTMPyP) form self‐assembled leaf‐like structures. These were obtained through electrostatic and π–π stacking interactions, as indicated by the redshift of the metalloporphyrin Soret band throughout the pH range of 6–12. Voltammetry and XPS measurements confirmed that CGO does not significantly affect the chemical environment of the metal ion in MnTMPyP. However, the effect of CGO is apparent when determining by rotating ring disk electrode (RRDE) voltammetry the ability of CGO‐Mn IV TMPyP films to catalyze water oxidation and evolve oxygen. The amount of O 2 evolved at pH 10 and 1.6 V versus Ag/AgCl is 50 % higher than that of MnTMPyP films. When used for the photoelectrochemical oxidation of water, CGO‐MnTMPyP films on iron/hematite foams exhibited substantial activity, as evidenced by the current density (0.54 mA/cm 2 at 1.23 V vs. NHE) and incident photons to current efficiency (IPCE; 9.0 % at 1.43 V vs. NHE) measured at pH 10.