An intensity modulated photocurrent spectroscopy study of the role of titanium in thick hematite photoanodes

Author(s)

Rodriguez-Gutierrez, Ingrid ^{[1, 2]} ; Souza Junior, Joao B. ^[1] ; Leite, Edson R. ^{[3, 1]} ; Vayssieres, Lionel ^[4] ; Souza, Flavio L. ^{[1, 2]}

Affiliation

^[1] Brazilian Ctr Res Energy & Mat CNPEM, Brazilian Nanotechnol Natl Lab LNNano, BR-13083970 Campinas - Brazil

^[2] Fed Univ ABC UFABC, Ctr Ciencias Nat & Humanas CCNH, BR-09210580 Santo Andre, SP - Brazil

^[3] Univ Fed Sao Carlos, Dept Quim, BR-13565905 Sao Carlos - Brazil

^[4] Xi An Jiao Tong Univ, Int Res Ctr Renewable Energy IRCRE, Sch Energy & Power Engn, State Key Lab Multiphase Flow Power Engn, Xian 710049 - Peoples R China

• Document type: Journal article
• Source: Applied Physics Letters; v. 119, n. 7 AUG 16 2021.
• Web of Science Citations: 0

Abstract

In this Letter, the role of Ti addition in thick hematite mesoporous photoanodes was elucidated by performing intensity modulated photocurrent spectroscopy (IMPS) monitoring its charge carrier dynamics during water oxidation. Interface engineering associated with doping of hematite is crucial to develop highly efficient thick photoanodes. Photoelectrochemical data recorded under front- and back-side illumination show that Ti insertion mitigates the collection deficit faced by hematite due to an energy barrier decrease between the grains and a change in the surface chemistry. IMPS reveals that Ti clearly influences the hematite film performance by increasing the charge separation efficiency due to its segregation at the hematite interface. However, Ti insertion does not enhance the kinetics of water oxidation at the solid-liquid interface. These facts indicate that Ti mainly affects the hematite electronic properties instead of accelerating the surface processes. This comprehensive understanding of the electronic transport and charge carrier dynamics in Ti:hematite photoanodes enables the control and design of better interfaces for more efficient photoelectrochemical water splitting. (AU)

• FAPESP's process: 19/06654-9 - Incorporation of metallic nanoparticles in hematite photoelectrodes: effect of solid-solid interface on optical and electrical properties
• Grantee: Ingrid Guadalupe Rodriguez Gutierrez
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 17/11986-5 - Generation and storage of New Energy: bringing technological development for the country
• Grantee: Ana Flávia Nogueira
• Support Opportunities: Research Grants - Research Centers in Engineering Program
• FAPESP's process: 13/07296-2 - CDMF - Center for the Development of Functional Materials
• Grantee: Elson Longo da Silva
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 17/02317-2 - Interfaces in materials: electronic, magnetic, structural and transport properties
• Grantee: Adalberto Fazzio
• Support Opportunities: Research Projects - Thematic Grants