Ab initio studies of bimetallic-doped {0001} hematite surface for enhanced photoelectrochemical water splitting

dc.contributor.authorSimfukwe, Joseph
dc.contributor.authorMapasha, Refilwe Edwin
dc.contributor.authorBraun, Artur
dc.contributor.authorDiale, M. (Mmantsae Moche)
dc.contributor.emailmmantsae.diale@up.ac.zaen_ZA
dc.date.accessioned2021-09-13T08:00:43Z
dc.date.available2021-09-13T08:00:43Z
dc.date.issued2021-08
dc.description.abstractFirst-principles calculations based on density functional theory (DFT) were carried out to study the energetic stability and electronic properties of a bimetallic-doped α-Fe2O3 photoanode surface with (Zn, Ti) and (Zn, Zr) pairs for enhanced PEC water splitting. The doped systems showed negative formation energies under both O-rich and Fe-rich conditions which make them thermodynamically stable and possible to be synthesised. It is found that in a bimetallic (Zn, Ti)- doped system, at a doping concentration of 4.20% of Ti, the bandgap decreases from 2.1 eV to 1.80 eV without the formation of impurity states in the bandgap. This is favourable for increased photon absorption and efficient movement of charges from the valance band maximum (VBM) to the conduction band minimum (CBM). In addition, the CBM becomes wavy and delocalised, suggesting a decrease in the charge carrier mass, enabling electron–holes to successfully diffuse to the surface, where they are needed for water oxidation. Interestingly, with single doping of Zr at the third layer (L3) of Fe atoms of the {0001} α-Fe2O3 surface, impurity levels do not appear in the bandgap, at both concentrations of 2.10% and 4.20%. Furthermore, at 2.10% doping concentration of α-Fe2O3 with Zr, CBM becomes delocalised, suggesting improved carrier mobility, while the bandgap is altered from 2.1 eV to 1.73 eV, allowing more light absorption in the visible region. Moreover, the photocatalytic activities of Zr-doped hematite could be improved further by codoping it with Zn because Zr is capable of increasing the conductivity of hematite by the substitution of Fe3+ with Zr4+, while Zn can foster the surface reaction and reduce quick recombination of the electron–hole pairs.en_ZA
dc.description.departmentPhysicsen_ZA
dc.description.librarianpm2021en_ZA
dc.description.sponsorshipThe Copperbelt University and Ministry of Higher Education in Zambia through the Support to Science Technology and Engineering Project (SSTEP); Production of Liquid Solar Fuels from CO2 and Water: Using Renewable Energy Resources Swiss South African Joint Research Programme (SSAJRP) NRF—Research Foundation.en_ZA
dc.description.urihttp://www.mdpi.com/journal/catalystsen_ZA
dc.identifier.citationSimfukwe, J.; Mapasha, R.E.; Braun, A.; Diale, M. Ab Initio Studies of Bimetallic-Doped {0001} Hematite Surface for Enhanced Photoelectrochemical Water Splitting. Catalysts 2021, 11, 940. https://doi.org/10.3390/catal11080940.en_ZA
dc.identifier.issn2073-4344 (online)
dc.identifier.other10.3390/catal11080940
dc.identifier.urihttp://hdl.handle.net/2263/81785
dc.language.isoenen_ZA
dc.publisherMDPIen_ZA
dc.rights© 2021 by the authors. Licensee: MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license.en_ZA
dc.subjectFirst principlesen_ZA
dc.subjectBimetallic dopingen_ZA
dc.subjectWater splittingen_ZA
dc.subjectBandgapen_ZA
dc.subjectDensity functional theory (DFT)en_ZA
dc.titleAb initio studies of bimetallic-doped {0001} hematite surface for enhanced photoelectrochemical water splittingen_ZA
dc.typeArticleen_ZA

Files

Original bundle

Now showing 1 - 1 of 1
Loading...
Thumbnail Image
Name:
Simfukwe_AbInitio_2021.pdf
Size:
2.94 MB
Format:
Adobe Portable Document Format
Description:
Article

License bundle

Now showing 1 - 1 of 1
Loading...
Thumbnail Image
Name:
license.txt
Size:
1.75 KB
Format:
Item-specific license agreed upon to submission
Description: