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Enabling unassisted solar water splitting by iron oxide and silicon.

Jang JW, Du C, Ye Y, Lin Y, Yao X, Thorne J, Liu E, McMahon G, Zhu J, Javey A, Guo J, Wang D - Nat Commun (2015)

Bottom Line: Here we show that, by using the prototypical photoanode material of haematite as a study tool, structural disorders on or near the surfaces are important causes of the low photovoltages.We develop a facile re-growth strategy to reduce surface disorders and as a consequence, a turn-on voltage of 0.45 V (versus reversible hydrogen electrode) is achieved.This result permits us to construct a photoelectrochemical device with a haematite photoanode and Si photocathode to split water at an overall efficiency of 0.91%, with NiFeOx and TiO2/Pt overlayers, respectively.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Merkert Chemistry Center, Boston College, 2609 Beacon St, Chestnut Hill, Massachusetts 02467, USA.

ABSTRACT
Photoelectrochemical (PEC) water splitting promises a solution to the problem of large-scale solar energy storage. However, its development has been impeded by the poor performance of photoanodes, particularly in their capability for photovoltage generation. Many examples employing photovoltaic modules to correct the deficiency for unassisted solar water splitting have been reported to-date. Here we show that, by using the prototypical photoanode material of haematite as a study tool, structural disorders on or near the surfaces are important causes of the low photovoltages. We develop a facile re-growth strategy to reduce surface disorders and as a consequence, a turn-on voltage of 0.45 V (versus reversible hydrogen electrode) is achieved. This result permits us to construct a photoelectrochemical device with a haematite photoanode and Si photocathode to split water at an overall efficiency of 0.91%, with NiFeOx and TiO2/Pt overlayers, respectively.

No MeSH data available.


Related in: MedlinePlus

Morphology evolution of haematite as a result of the re-growth treatments.Scanning electron micrographs image of (a) sdH, (b) rgH I, (c) rgH II and (d) rgH III; scale bars, 100 nm. Magnified views of selected areas in the main frames are presented in the insets. Transmission electron micrographs of focused ion beam prepared cross-sectional samples of (e) sdH, (f) rgH I, (g) rgH II and (h) rgH III, scale bars, 500 nm.
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f3: Morphology evolution of haematite as a result of the re-growth treatments.Scanning electron micrographs image of (a) sdH, (b) rgH I, (c) rgH II and (d) rgH III; scale bars, 100 nm. Magnified views of selected areas in the main frames are presented in the insets. Transmission electron micrographs of focused ion beam prepared cross-sectional samples of (e) sdH, (f) rgH I, (g) rgH II and (h) rgH III, scale bars, 500 nm.

Mentions: Electron micrographs (Fig. 3) landed us further support on the understanding that the re-growth strategy is effective in re-organizing haematite surfaces. Small (∼70 nm), random structures were most prominent for sdH; the orderliness of the structures was clearly improved after the second regrowth treatment (rgH II). Further regrowth (rgH III), nevertheless, resulted in overgrowth that affects the PEC performance negatively (Supplementary Fig. 2). The PEC behaviours are well corroborated with the changes in the LO peak intensities (Fig. 2b) and increased (104) peak intensities (Fig. 2a).


Enabling unassisted solar water splitting by iron oxide and silicon.

Jang JW, Du C, Ye Y, Lin Y, Yao X, Thorne J, Liu E, McMahon G, Zhu J, Javey A, Guo J, Wang D - Nat Commun (2015)

Morphology evolution of haematite as a result of the re-growth treatments.Scanning electron micrographs image of (a) sdH, (b) rgH I, (c) rgH II and (d) rgH III; scale bars, 100 nm. Magnified views of selected areas in the main frames are presented in the insets. Transmission electron micrographs of focused ion beam prepared cross-sectional samples of (e) sdH, (f) rgH I, (g) rgH II and (h) rgH III, scale bars, 500 nm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4490416&req=5

f3: Morphology evolution of haematite as a result of the re-growth treatments.Scanning electron micrographs image of (a) sdH, (b) rgH I, (c) rgH II and (d) rgH III; scale bars, 100 nm. Magnified views of selected areas in the main frames are presented in the insets. Transmission electron micrographs of focused ion beam prepared cross-sectional samples of (e) sdH, (f) rgH I, (g) rgH II and (h) rgH III, scale bars, 500 nm.
Mentions: Electron micrographs (Fig. 3) landed us further support on the understanding that the re-growth strategy is effective in re-organizing haematite surfaces. Small (∼70 nm), random structures were most prominent for sdH; the orderliness of the structures was clearly improved after the second regrowth treatment (rgH II). Further regrowth (rgH III), nevertheless, resulted in overgrowth that affects the PEC performance negatively (Supplementary Fig. 2). The PEC behaviours are well corroborated with the changes in the LO peak intensities (Fig. 2b) and increased (104) peak intensities (Fig. 2a).

Bottom Line: Here we show that, by using the prototypical photoanode material of haematite as a study tool, structural disorders on or near the surfaces are important causes of the low photovoltages.We develop a facile re-growth strategy to reduce surface disorders and as a consequence, a turn-on voltage of 0.45 V (versus reversible hydrogen electrode) is achieved.This result permits us to construct a photoelectrochemical device with a haematite photoanode and Si photocathode to split water at an overall efficiency of 0.91%, with NiFeOx and TiO2/Pt overlayers, respectively.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Merkert Chemistry Center, Boston College, 2609 Beacon St, Chestnut Hill, Massachusetts 02467, USA.

ABSTRACT
Photoelectrochemical (PEC) water splitting promises a solution to the problem of large-scale solar energy storage. However, its development has been impeded by the poor performance of photoanodes, particularly in their capability for photovoltage generation. Many examples employing photovoltaic modules to correct the deficiency for unassisted solar water splitting have been reported to-date. Here we show that, by using the prototypical photoanode material of haematite as a study tool, structural disorders on or near the surfaces are important causes of the low photovoltages. We develop a facile re-growth strategy to reduce surface disorders and as a consequence, a turn-on voltage of 0.45 V (versus reversible hydrogen electrode) is achieved. This result permits us to construct a photoelectrochemical device with a haematite photoanode and Si photocathode to split water at an overall efficiency of 0.91%, with NiFeOx and TiO2/Pt overlayers, respectively.

No MeSH data available.


Related in: MedlinePlus