Controlled Surface Modification of ZnO Nanostructures with Amorphous TiO2 for Photoelectrochemical Water Splitting. (3rd June 2019)

• Record Type: Journal Article
• Authors: Gasparotto, Alberto; Maccato, Chiara; Sada, Cinzia; Carraro, Giorgio; Kondarides, Dimitris I.; Bebelis, Symeon; Petala, Athanasia; La Porta, Andrea; Altantzis, Thomas; Barreca, Davide
• Is Part Of: Advanced sustainable systems. Volume 3:Number 9(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-06-03
• Subjects: heterojunctions -- photoelectrochemistry -- TiO2 -- water splitting -- ZnO; Sustainable living -- Periodicals; Sustainability -- Periodicals; Green technology -- Periodicals; Periodicals; 628
• DOI: 10.1002/adsu.201900046
• Languages: English
• ISSNs: 2366-7486

Abstract

Abstract: 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–TiO2 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 TiO2 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/TiO2 heterojunctions yielding an improved photocarrier separation, show that the target nanocomposites are attractive photoanodes for efficient PEC water splitting. Abstract : ZnO–TiO2 nanocomposites for photoelectrochemical water splitting are fabricated by chemical vapor deposition of ZnO nanosystems on ITO substrates, functionalized with TiO2 through sputtering, and finally annealed in air. A proper tailoring of processing conditions enables photocurrents of ≈0.9 mA cm −2 at 0.25 V versus Ag/AgCl under simulated sunlight, opening the doors to future implementations for sustainable energy generation.