title: Formation of Semimetallic Cobalt Telluride Nanotube Film via Anion Exchange Tellurization Strategy in Aqueous Solution for Electrocatalytic Applications.
abstract: Metal telluride nanostructures have demonstrated several potential applications particularly in harvesting and storing green energy. Metal tellurides are synthesized by tellurization process performed basically at high temperature in reducing gas atmosphere, which makes the process expensive and complicated. The development of a facile and economical process for desirable metal telluride nanostructures without complicated manipulation is still a challenge. In an effort to develop an alternative strategy of tellurization, herein we report a thin film formation of self-standing cobalt telluride nanotubes on various conducting and nonconducting substrates using a simple binder-free synthetic strategy based on anion exchange transformation from a thin film of cobalt hydroxycarbonate nanostructures in aqueous solution at room temperature. The nanostructured films before and after ion exchange transformation reaction are characterized using field emission scanning electron microscope, energy dispersive X-ray analyzer, X-ray photoelectron spectroscopy, thin film X-ray diffraction technique, high resolution transmission electron microscope, and selected area electron diffraction analysis technique. After the ion exchange transformation of nanostructures, the film shows conversion from insulator to highly electrical conductive semimetallic characteristic. When used as a counter electrode in I3(-)/I(-) redox electrolyte based dye-sensitized solar cells, the telluride film exhibits an electrocatalytic reduction activity for I3(-) with a demonstration of solar-light to electrical power conversion efficiency of 8.10%, which is highly competitive to the efficiency of 8.20% exhibited by a benchmarked Pt-film counter electrode. On the other hand, the telluride film electrode also demonstrates electrocatalytic activity for oxygen evolution reaction from oxidation of water.
authors.affiliation: Department of Chemistry, Hanyang University , Seongdong-gu, Haengdang-dong 17, Seoul 133-791, Republic of Korea.
authors.forename: Supriya A
authors.initials: SA
authors.lastname: Patil
authors.affiliation: Department of Chemistry, Hanyang University , Seongdong-gu, Haengdang-dong 17, Seoul 133-791, Republic of Korea.
authors.forename: Eun-Kyung
authors.initials: EK
authors.lastname: Kim
authors.affiliation: Department of Chemistry, Hanyang University , Seongdong-gu, Haengdang-dong 17, Seoul 133-791, Republic of Korea.
authors.forename: Nabeen K
authors.initials: NK
authors.lastname: Shrestha
authors.affiliation: Sungshin Women's University, School of Biological Science and Chemistry , 55 Dobong-ro 76 ga-gil, Gangbuk-gu, Seoul 142-732, Republic of Korea.
authors.forename: Jinho
authors.initials: J
authors.lastname: Chang
authors.affiliation: Energy Storage Research Centre, Korea Institute of Science and Technology ,Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136791, Republic of Korea.
authors.forename: Joong Kee
authors.initials: JK
authors.lastname: Lee
authors.affiliation: Department of Chemistry, Hanyang University , Seongdong-gu, Haengdang-dong 17, Seoul 133-791, Republic of Korea.
authors.forename: Sung-Hwan
authors.initials: SH
authors.lastname: Han
keywords: cobalt telluride; electrocatalysis; ion exchange; tellurization; thin film