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A Delaminated Defect‐Rich ZrO 2 Hierarchical Nanowire Photocathode for Efficient Photoelectrochemical Hydrogen Evolution
Author(s) -
Rahman Md Anisur,
Thomas Joseph P.,
Leung Kam Tong
Publication year - 2018
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201701234
Subject(s) - photocathode , materials science , photocurrent , water splitting , reversible hydrogen electrode , nanowire , hydrogen , faraday efficiency , oxygen evolution , energy conversion efficiency , hydrogen production , chemical engineering , photocatalysis , nanotechnology , electrode , optoelectronics , anode , electrochemistry , working electrode , catalysis , electron , biochemistry , chemistry , physics , organic chemistry , quantum mechanics , engineering
An efficient way to combat the energy crisis and the greenhouse gas effect of fossil fuels is the production of hydrogen fuel from solar‐driven water splitting reaction. Here, this study presents a p‐type ZrO 2 nanoplate‐decorated ZrO 2 nanowire photocathode with a high photoconversion efficiency that makes it potentially viable for commercial solar H 2 production. The composition of oxygen vacancy defects, low charge carrier transport property, and high specific surface area of these as‐grown hierarchical nanowires are further improved by an hydrofluoric acid (HF) treatment, which causes partial delamination and produces a thin amorphous ZrO 2 layer on the surface of the as‐grown nanostructured film. The presence of different types of oxygen vacancies (neutral, singly charged, and doubly charged defects) and their compositional correlation to the Zr x + oxidation states (4 > x > 2) are found to affect the charge transfer process, the p‐type conductivity, and the photocatalytic activity of the ZrO 2 nanostructured film. The resulting photocathode provides the highest overall photocurrent (−42.3 mA cm −2 at 0 V vs reversible hydrogen electrode (RHE)) among all the photocathodes reported to date, and an outstanding 3.1% half‐cell solar‐to‐hydrogen conversion efficiency with a Faradaic efficiency of 97.8%. Even more remarkable is that the majority of the photocurrent (69%) is produced in the visible light region.