Year-end Sale % OFF 
Abstract
For the first time, hematite (α-Fe2O3) crystals were electrochemically deposited over vertically aligned conductive zinc oxide nanorods (NR) to form a specially designed 3D heterostructure with a unique triple layer structure. The structure formed with a thin layer of ZnFe2O4 sandwiched between the hematite and the ZnO, which forms a barrier to reduce the back migration of holes. Hence, the charge separation is significantly improved. The small unequal bandgaps of α-Fe2O3 and ZnFe2O4 help to enhance and broaden visible light absorption. The electron transportation was further improved by yttrium doping in the ZnO (YZnO) NRs, resulting in increased conductivity. This allowed the vertically aligned NRs to perform as electron highways, which also behave as effective optical waveguides for improved light trapping and absorption, since ZnO absorbs little visible light. All these benefits made the unique structures suitable for high performance photoelectrochemical (PEC) water splitting. Optimisation of α-Fe2O3 thickness led to a photocurrent density improvement from 0.66 to 0.95 mA cm−2 at 1.23 VRHE. This was further improved to 1.59 mA cm−2 by annealing at 550 °C for 3 h, representing a record-breaking photocurrent for α-Fe2O3/ZnO systems. Finally IPCE confirmed the successful generation and transfer of photoelectrons under visible light excitation in the specifically designed heterostructure photoanode, with 5% efficiency for blue light, and 15% for violet light.
Highlights
Great innovation and radical new solutions are required to meet the threat posed by climate change [1]
This allowed the vertically aligned NRs to perform as electron highways, which behave as effective optical waveguides for improved light trapping and absorption, since ZnO absorbs little visible light
We present a 3D electrode platform based on vertically aligned transparent conductive oxide (TCO) nanorods
Summary
Great innovation and radical new solutions are required to meet the threat posed by climate change [1]. One of the key factors restricting electrification is energy storage [2]. PEC water splitting provides an elegant solution, harvesting and storing solar energy in chemical H2 bonds [3,4,5]. Requiring aqueous insolubility and band edge positions suitable to surmount the over potentials for water redox, metal oxides such as TiO2 and ZnO have been the focus of much literature for this application [6,7,8,9]. Boasting superior electronic properties and the simple solution growth of nanostructures, ZnO has yet to reach its full potential for solar water splitting [10]. The main restriction is its large band gap, 3.2 eV, rendering this material unable to absorb most sunlight, Nanotechnology 31 (2020) 265403 this factor can be negated through the use of doping and coating [11]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
