Improving Photoelectrochemical Hydrogen Generation from Water Splitting using Ultrathin Overlayers on Hematite Photo-anodes

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dc.contributor.authorLevinsson, Alexander
dc.contributor.departmentChalmers tekniska högskola / Institutionen för fysik (Chalmers)sv
dc.contributor.departmentChalmers University of Technology / Department of Physics (Chalmers)en
dc.date.accessioned2019-07-03T14:31:37Z
dc.date.available2019-07-03T14:31:37Z
dc.date.issued2017
dc.description.abstractSolar energy is the energy source for the future, because it is renewable and environmentally safe. An application to convert the solar energy into a useful energy form is photoelectrochemical (PEC) water splitting, in which the solar energy is converted to chemical energy in hydrogen gas. Hematite (-Fe2O3) is one of the most promising semiconductors that are used in PEC cells, mainly because of its band gap of 1.9 − 2.2 eV, its chemical stability, and that it is an abundant material. Hematite is used as a photo-anode in the PEC cell, but its performance is limited due to for instance poor oxidation kinetics at the hematite/electrolyte interface. In this work, three different ultrathin overlayers (FeOOH, NiOOH, NiFeOx) are deposited on hematite in order to improve the performance of the PEC cell by reducing recombination of photogenerated electron−hole pairs and facilitate hole transport at the hematite/overlayer/electrolyte interface. With these overlayers, the photocurrent density of hematite is increased and the onset potential is lowered. The hematite electrode with the FeOOH overlayer shows the best performance, where the photocurrent density is increased from 0.087 mA/cm2 for bare hematite to 0.275 mA/cm2 at 1.23 VRHE under 1 sun illumination, and the onset potential is lowered by 220 mV compared to bare hematite. This improved performance is a result of the improved oxidation kinetics, which for instance can be attributed to an increased surface charge transfer efficiency.
dc.identifier.urihttps://hdl.handle.net/20.500.12380/250402
dc.language.isoeng
dc.setspec.uppsokPhysicsChemistryMaths
dc.subjectFysik
dc.subjectBuilding Futures
dc.subjectGrundläggande vetenskaper
dc.subjectHållbar utveckling
dc.subjectKemi
dc.subjectKemiteknik
dc.subjectEnergi
dc.subjectInnovation och entreprenörskap (nyttiggörande)
dc.subjectMaterialvetenskap
dc.subjectPhysical Sciences
dc.subjectBuilding Futures
dc.subjectBasic Sciences
dc.subjectSustainable Development
dc.subjectChemical Sciences
dc.subjectChemical Engineering
dc.subjectEnergy
dc.subjectInnovation & Entrepreneurship
dc.subjectMaterials Science
dc.titleImproving Photoelectrochemical Hydrogen Generation from Water Splitting using Ultrathin Overlayers on Hematite Photo-anodes
dc.type.degreeExamensarbete för masterexamensv
dc.type.degreeMaster Thesisen
dc.type.uppsokH
local.programmeApplied physics (MPAPP), MSc
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