Characterization of hematite nanowire arrays synthesized by atmospheric plasma.

Hematite;Water splitting;Photoelectrochemistry;Nanowire;Solar cell;Iron oxide

Harry Benjamin Russell

University:University of Louisville

Department:Chemical Engineering

关键词: Hematite;    Water splitting;    Photoelectrochemistry;    Nanowire;    Solar cell;    Iron oxide;   

Others  :  https://ir.library.louisville.edu/cgi/viewcontent.cgi?article=2241&context=etd

美国|英语

来源: The Universite of Louisville's Institutional Repository

【 摘 要 】

Hematite synthesized by low pressure oxygen plasma has been shown previously to exhibit promising characteristics as a photo-anode for a photoelectrochemical water splitting cell. It is cheap, stable and has a 2.1 eV bandgap and exhibits a significant photoactivity due to the presence of a thin interfacial layer and oxygen vacancy planes throughout the sample. Unfortunately, due to the nature of vacuum systems, this process would be difficult to scale-up and as such atmospheric plasma synthesis was explored. Photoactive hematite nanowire arrays were synthesized using an atmospheric microwave plasma jet reactor. They exhibited all of the characteristics of those synthesized under low pressure except for poor photoactivity due to a thin amorphous oxide layer on the surface layer. This oxide layer was removed by hydrofluoric acid etching and subsequently produced a significant photoactivity. Further synthesis improvements have yielded hematite nanowire arrays with no amorphous oxide layer present. Removal of nanowires from the nanowire array decreased the subsequent photoactivity of the electrode, indicating that photoactivity is due to the nanowires present on the sample and not due to the thin interfacial layer. Testing at different light intensities under constant voltage shows that photoactivity of hematite nanowire arrays is linearly dependent on light intensity.