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Optimization of $α-Fe_{2}O_{3}$ Nanopillars Diameters for Photoelectrochemical Enhancement of $α-Fe_{2}O_{3}-TiO_{2}$ Heterojunction
| Content Provider | MDPI |
|---|---|
| Author | Baldovi, Herme |
| Copyright Year | 2021 |
| Description | Global warming is pushing the world to seek to green energy sources and hydrogen is a good candidate to substitute fossil fuels in the short term. In future, it is expected that production of hydrogen will be carried out through photo-electrocatalysis. In this way, suitable electrodes that acts as photoanode absorbing the incident light are needed to catalyse water splitting reaction. Hematite $(α-Fe_{2}O_{3}$) is one of the most attractive semiconductors for this purpose since it is a low-cost material and it has a suitable band gap of 2.1 eV, which allows the absorption of the visible region. Although, hematite has drawbacks such as low carrier mobility and short holes diffusion lengths, that here it has been tried to overcome by nanoengineering the material, and by using a semiconductor as a scaffold that enhances charge carrier separation processes in the electrode. In this work, we fabricate ultrathin quasi transparent electrodes composed by highly ordered and self-standing hematite nanopillars of a few tens of nanometers length on FTO and $TiO_{2}$ supports. Photoanodes were fabricated utilizing electron beam evaporation technique and anodized aluminum oxide templates with well-defined pores diameters. Thus, the activity of the compact layer hematite photoanode is compared with the photoanodes fabricated with nanopillars of controllable diameters (i.e., 90, 260 and 400 nm) to study their influence on charge separation processes. Results indicated that optimal $α-Fe_{2}O_{3}$ photoanodes performance are obtained when nanopillars reach hundreds of nanometers in diameter, achieving for photoanodes with 400 nm nanopillars onto $TiO_{2}$ supports the highest photocurrent density values. |
| Starting Page | 2019 |
| e-ISSN | 20794991 |
| DOI | 10.3390/nano11082019 |
| Journal | Nanomaterials |
| Issue Number | 8 |
| Volume Number | 11 |
| Language | English |
| Publisher | MDPI |
| Publisher Date | 2021-08-07 |
| Access Restriction | Open |
| Subject Keyword | Nanomaterials Electrochemistry Hematite Nanopillars Diameter Electron Beam Evaporation Water Splitting Tio2 Support Hydrogen Heterojunctions |
| Content Type | Text |
| Resource Type | Article |
