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Controlled Surface Modification of ZnO Nanostructures with Amorphous TiO 2 for Photoelectrochemical Water Splitting
Author(s) -
Gasparotto Alberto,
Maccato Chiara,
Sada Cinzia,
Carraro Giorgio,
Kondarides Dimitris I.,
Bebelis Symeon,
Petala Athanasia,
La Porta Andrea,
Altantzis Thomas,
Barreca Davide
Publication year - 2019
Publication title -
advanced sustainable systems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.499
H-Index - 24
ISSN - 2366-7486
DOI - 10.1002/adsu.201900046
Subject(s) - materials science , photocurrent , water splitting , heterojunction , nanocomposite , amorphous solid , nanostructure , nanotechnology , chemical engineering , indium tin oxide , optoelectronics , photocatalysis , thin film , biochemistry , chemistry , organic chemistry , engineering , catalysis
The utilization of solar radiation to trigger photoelectrochemical (PEC) water splitting has gained interest for sustainable energy production. In this study, attention is focused on the development of ZnO–TiO 2 nanocomposite photoanodes. The target systems are obtained by growing porous arrays of highly crystalline, elongated ZnO nanostructures on indium tin oxide (ITO) by chemical vapor deposition. Subsequently, the obtained nanodeposits are functionalized with TiO 2 via radio frequency‐sputtering for different process durations, and subjected to final annealing in air. Characterization results demonstrate the successful formation of high purity composite systems in which the surface of ZnO nanostructures is decorated by ultra‐small amounts of amorphous titania, whose content can be conveniently tailored as a function of deposition time. Photocurrent density measurements in sunlight‐triggered water splitting highlight a remarkable performance enhancement with respect to single‐phase zinc and titanium oxides, with up to a threefold photocurrent increase compared to bare ZnO. These results, mainly traced back to the formation of ZnO/TiO 2 heterojunctions yielding an improved photocarrier separation, show that the target nanocomposites are attractive photoanodes for efficient PEC water splitting.