Systematic exploration of WO3/TiO2 heterojunction phase space for applications in photoelectrochemical water splitting

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Title: Systematic exploration of WO3/TiO2 heterojunction phase space for applications in photoelectrochemical water splitting
Authors: Pinto, F
Wilson, A
Moss, B
Kafizas, A
Item Type: Journal Article
Abstract: Recent work has shown that heterojunction photoelectrodes can achieve synergistically higher water splitting activity than their parent materials. To optimize the performance in such layered systems, it is necessary to develop new methods capable of assessing heterojunction phase space. Herein, we explore WO3/TiO2 heterojunction phase space as a model system. Using chemical vapor deposition, 71 unique photoanodes were grown (15 single-layer; 56 heterojunctions). The materials were physically characterized using X-ray diffraction, Raman spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy analysis, and ultraviolet–visible transmission spectroscopy. Various key performance indicators were measured. Within this WO3/TiO2 heterojunction phase space, the onset potentials ranged from ∼0.45 to ∼0.81 VRHE; the incident-photon-to-current efficiencies at 350, 375, and 400 nm ranged from ∼0.6 to ∼50.9, ∼0.1 to ∼30.0, and ∼0 to ∼15.6%, respectively; and the theoretical solar photocurrents ranged from ∼0.01 to ∼0.94 mA cm–2. Contour plots allowed us to identify regions of heterojunction phase space with high activity and establish trends. We identified an electronic barrier to charge transfer between the heterojunction layers that required a sufficiently high applied potential (≥1.0 VRHE) to be surpassed for synergetic improvements in activity to be observed. We recommend that the methods developed herein, for assessing the performance of sample libraries of heterojunction photoelectrodes, be used alongside combinatorial synthesis methods and high-throughput photoelectrochemical measurements to optimize promising heterojunction systems more rigorously and rapidly.
Issue Date: 7-Jan-2022
Date of Acceptance: 1-Jan-2022
URI: http://hdl.handle.net/10044/1/94829
DOI: 10.1021/acs.jpcc.1c08403
ISSN: 1932-7447
Publisher: American Chemical Society
Start Page: 871
End Page: 884
Journal / Book Title: The Journal of Physical Chemistry C: Energy Conversion and Storage, Optical and Electronic Devices, Interfaces, Nanomaterials, and Hard Matter
Volume: 126
Issue: 2
Copyright Statement: © 2022 American Chemical Society
Sponsor/Funder: The Royal Society
Funder's Grant Number: RSG\R1\180434
Keywords: Science & Technology
Physical Sciences
Technology
Chemistry, Physical
Nanoscience & Nanotechnology
Materials Science, Multidisciplinary
Chemistry
Science & Technology - Other Topics
Materials Science
NANOTUBE ARRAYS
TIO2 NANOTUBES
WO3
FILMS
PHOTOANODES
PERFORMANCE
PHOTOLYSIS
STABILITY
CATALYSTS
KINETICS
Science & Technology
Physical Sciences
Technology
Chemistry, Physical
Nanoscience & Nanotechnology
Materials Science, Multidisciplinary
Chemistry
Science & Technology - Other Topics
Materials Science
NANOTUBE ARRAYS
TIO2 NANOTUBES
WO3
FILMS
PHOTOANODES
PERFORMANCE
PHOTOLYSIS
STABILITY
CATALYSTS
KINETICS
Physical Chemistry
03 Chemical Sciences
09 Engineering
10 Technology
Publication Status: Published
Online Publication Date: 2022-01-07
Appears in Collections:Chemistry