Highly flexible transparent substrate-free photoanodes using ZnO nanowires on nickel microfibers

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 363; pp. 13 - 22
• Main Authors: Seok Jo, Hong, Samuel, Edmund, Kwon, Hyuk-Jin, Joshi, Bhavana, Kim, Min-Woo, Kim, Tae-Gun, Swihart, Mark T., Yoon, Sam S.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.05.2019
• Subjects: Flexible; Microfibers; Nanowires; Nickel; Photoanode; Substrate-free; Transparent; ZnO; Flexible; Transparent; Microfibers; Substrate-free; ZnO; Nickel; Nanowires; Photoanode
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2019.01.099

•Breakthrough demonstration of freestanding flexible high-performance photoanodes.•Uniform growth of ZnO nanowires improves photoelectrochemical performance.•ZnO NW/Ni fiber photoanode produces photocurrent density of 1.14 mA/cm2 at 0.4 V vs Ag/AgCl.•Unique morphology provides exceptional stability even after 1000 bending cycles. We demonstrate impressive performance of photoanodes comprising ZnO nanowires grown over nickel fibers for efficient water splitting. The photoanode is substrate-free and flexible, exhibiting excellent stability (∼98%) in photocurrent density even after 1000 bending cycles. The hierarchically structured ZnO nanowires on nickel microfibers synergistically provide many accessible electrochemical sites and enhance the photocurrent density to 1.14 mA/cm2 at a voltage of 0.4 V vs. Ag/AgCl. The one- and two-dimensional structures of the ZnO nanowires over nickel microfibers enable an efficient charge-transport mechanism that supports high light-harvesting efficiency. Scanning and transmission electron microscopy are used to study the morphologies of the samples in detail, while X-ray diffraction confirms the metallic state of Ni and the crystallinity of ZnO.