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Robust Sub‐Monolayers of Co 3 O 4 Nano‐Islands: A Highly Transparent Morphology for Efficient Water Oxidation Catalysis
Author(s) -
Liu Guanyu,
Karuturi Siva Krishna,
Simonov Alexandr N.,
Fekete Monika,
Chen Hongjun,
Nasiri Noushin,
Le Nhien H.,
Reddy Narangari Parvathala,
Lysevych Mykhaylo,
Gengenbach Thomas R.,
Lowe Adrian,
Tan Hark Hoe,
Jagadish Chennupati,
Spiccia Leone,
Tricoli Antonio
Publication year - 2016
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201600697
Subject(s) - overpotential , materials science , water splitting , monolayer , catalysis , oxygen evolution , chemical engineering , aqueous solution , nanoparticle , electrochemistry , photocatalysis , nanotechnology , electrode , chemistry , biochemistry , engineering
The scalable synthesis of highly transparent and robust sub‐monolayers of Co 3 O 4 nano‐islands, which efficiently catalyze water oxidation, is reported. Rapid aerosol deposition of Co 3 O 4 nanoparticles and thermally induced self‐organization lead to an ultra‐fine nano‐island morphology with more than 94% light transmission at a wavelength of 500 nm. These transparent sub‐monolayers demonstrate a remarkable mass‐weighted water oxidation activity of 2070–2350 A g Co3O4 −1 and per‐metal turnover frequency of 0.38–0.62 s −1 at an overpotential of 400 mV in 1 m NaOH aqueous solution. This mixed valent cobalt oxide structure exhibits excellent long‐term electrochemical and mechanical stability preserving the initial catalytic activity over more than 12 h of constant current electrolysis and 1000 consecutive voltammetric cycles. The potential of the Co 3 O 4 nano‐islands for photoelectrochemical water splitting has been demonstrated by incorporation of co‐catalysts in GaN nanowire photoanodes. The Co 3 O 4 ‐GaN photoanodes reveal significantly reduced onset overpotentials, improved photoresponse and photostability compared to the bare GaN ones. These findings provide a highly performing catalyst structure and a scalable synthesis method for the engineering of efficient photoanodes for integrated solar water‐splitting cells.