Title: Fe Substitutions Improve Spectral Response of Bi ₂ WO ₆ -Based Photoanodes

Abstract

The quest for a scalable solar fuel technology has stimulated a concerted effort to develop a metal oxide semiconductor for solar-driven photoelectrochemical water oxidation (oxygen evolution reaction) in an efficient and durable manner. So far, the search for such a metal oxide photoanode has highlighted the promise of Bi-based oxides, which have also been extensively studied for other photocatalyst applications. Bi₂WO₆ is a durable photocatalyst whose primary shortcoming is a 2.8 eV band gap that limits utilization of the solar spectrum. Improvements in visible photoresponse upon incorporation of Fe have been reported in the photocatalysis literature, motivating our use of high-throughput synthesis and photoelectrochemistry to determine the spectral photoresponse for Bi–W–Fe oxides synthesized under nonequilibrium conditions based on thermal oxidation of metallic films. Photoactivity down to 2 eV was achieved over a broad range of compositions, with detailed characterization of optimal compositions revealing that Fe incorporation increases the valence band position by 0.75 eV. Density functional theory calculations of Fe substitutions on W sites in Bi₂WO₆ are consistent with this valence band shift, providing a plausible explanation for the experiments. This Fe-mediated band tuning yields a ca. 2 eV band gap while retaining a turn-on potential for photoanodic current nearmore » 0.4 V versus RHE, which combined with the operational durability motivates continuous study and development of this promising class of metal oxide photoanodes.« less

Authors:

Zhou, Lan ^[1]; Peterson, Elizabeth A.  ^[2];

• Search DOE PAGES for author "Peterson, Elizabeth A."
• Search DOE PAGES for ORCID "0000-0001-5379-3604"

Richter, Matthias H.  ^[1];

• Search DOE PAGES for author "Richter, Matthias H."
• Search DOE PAGES for ORCID "0000-0003-0091-2045"

Lai, Yungchieh ^[1]; Neaton, Jeffrey B. ^[3]; Gregoire, John M.  ^[1]

• Search DOE PAGES for author "Gregoire, John M."
• Search DOE PAGES for ORCID "0000-0002-2863-5265"

---

+ Show Author Affiliations

1. Division of Engineering and Applied Science, California Institute of Technology, Pasadena, California91125, United States, Liquid Sunlight Alliance, California Institute of Technology, Pasadena, California91125, United States
2. Department of Physics, University of California, Berkeley, Berkeley, California94720, United States, Liquid Sunlight Alliance, Lawrence Berkeley National Laboratory, Berkeley, California94720, United States
3. Department of Physics, University of California, Berkeley, Berkeley, California94720, United States, Liquid Sunlight Alliance, Lawrence Berkeley National Laboratory, Berkeley, California94720, United States, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California94720, United States, Kavli Energy NanoSciences Institute, University of California, Berkeley, Berkeley, California94720, United States

Publication Date:

Thu Dec 15 00:00:00 EST 2022

Research Org.:

California Institute of Technology (CalTech), Pasadena, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1905148

Alternate Identifier(s):

OSTI ID: 1906936

Grant/Contract Number:  

SC0021266; AC02-05CH11231

Resource Type:

Published Article

Journal Name:

ACS Applied Energy Materials

Additional Journal Information:

Journal Name: ACS Applied Energy Materials Journal Volume: 5 Journal Issue: 12; Journal ID: ISSN 2574-0962

Publisher:

American Chemical Society

Country of Publication:

United States

Language:

English

Subject:

25 ENERGY STORAGE; combinatorial material discovery; electronic structure theory; magnetron co-sputtering; photoelectrochemistry; oxygen evolution reaction; metal oxide photoanode; bismuth tungstate