Microwave-assisted surface attachment of aluminium ions on <i>in situ</i> diluted titanium-doped hematite photoanodes for efficient photoelectrochemical water-splitting

Hwang, Jun Beom; Dhandole, Love Kumar; Anushkkaran, Periyasamy; Chae, Weon‐Sik; Choi, Sun Hee; Lee, Hyun Hwi; Jang, Jum Suk

doi:10.1039/d2se00459c

Cited by 9 publications

(8 citation statements)

References 54 publications

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“…The Sn 3d spectra exhibit a peak centered at 486.4 eV for Sn 3d 5/2 , confirming that the Sn 4+ dopants are diffused from the FTO and incorporated into the hematite lattice (Figure S5b). We can observe that the 8% Nb-HT shows a lower Sn content than the Bare-HT, which might be due to the Nb doping suppressing Sn 4+ ions from being diffused/doped into the crystal lattice. To further investigate the change in the crystal structure of the Nb-doped hematite photoanodes, Raman spectra have been studied.…”

Section: Resultsmentioning

confidence: 89%

Unveiling the Synchronized Effect of Bulk and Surface Dual Modification of In Situ Nb-Doping and Microwave-Assisted Co(OH)_x Cocatalyst for Boosting Photoelectrochemical Water Splitting of Fe₂O₃ Photoanodes

Anushkkaran

Koh

Chae

et al. 2023

ACS Sustainable Chem. Eng.

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Herein, in order to improve the conductivity and slack water oxidation kinetics of the hematite (α-Fe 2 O 3 ) photoanode, we propose the Nb-doped and Co(OH) x cocatalyst-deposited α-Fe 2 O 3 thin film photoanode (Nb-HT/Co(OH) x ) via in situ diluted hydrothermal and microwave-assisted methods. The as-prepared Nb-HT/ Co(OH) x thin-film photoanode exhibited a photocurrent density of 1.78 mA cm −2 at 1.23 V versus a reversible hydrogen electrode (RHE), which is 1.7-fold higher than that of the Bare-Fe 2 O 3 photoanode. The dual effect of Nb-doping and Co(OH) x deposition markedly improved the PEC performance through enhancing the charge carrier mobility and donor density in hematite, as well as accelerating the interfacial charge transfer kinetics at the electrode/electrolyte interface of the α-Fe 2 O 3 thin film photoanode. The Nb-HT/Co(OH) x photoanode displayed a high charge separation efficiency of 90% (at 1.23 V RHE ) and excellent stability over a 10 h period without any decrease. Detailed electrochemical analyses using electrochemical impedance spectroscopy (EIS), opencircuit potential (OCP), and accumulated charge density techniques disclosed the charge separation and transfer processes. This strategy of bulk and surface modification highlights a new approach to constructing a stable photoanode for sustainable solar energy conversion.

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Section: Resultsmentioning

confidence: 89%

Unveiling the Synchronized Effect of Bulk and Surface Dual Modification of In Situ Nb-Doping and Microwave-Assisted Co(OH)_x Cocatalyst for Boosting Photoelectrochemical Water Splitting of Fe₂O₃ Photoanodes

Anushkkaran

Koh

Chae

et al. 2023

ACS Sustainable Chem. Eng.

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“…This is due to the fact that Be 2+ does not generate Fe 2+ ions within the lattice. 41,42 On the other hand, however, Hf/Be-HT exhibited a higher N D compared to the Hf-HT. This phenomenon can be attributed to the Be 2+ is capable of modulating the effective charge of Fe 3+ to Fe 2+ on Table 1.…”

Section: ■ Results and Discussionmentioning

confidence: 93%

Unveiling the Significance of Diverse Valence State Second Dopants on Hf-Doped Fe₂O₃ Photoanodes for Enhanced Photoelectrochemical Water Splitting

Anushkkaran,

Kwon,

Koh

et al. 2024

ACS Sustainable Chem. Eng.

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Hematite (α-Fe 2 O 3 )-based photoanodes offer great potential for use in solar hydrogen production as part of efforts to construct a sustainable and renewable energy economy based on photoelectrochemical (PEC) water splitting. A co-doping modification is of the utmost significance for improving PEC performance. To develop an efficient photoanode, a comprehensive grasp of co-dopants with diverse valence states is necessary. Herein, we describe a hydrothermal and dip-coating approach to the fabrication of Hfdoped Fe 2 O 3 (Hf-HT) photoanodes co-doped with Be 2+ , Al 3+ , Si 4+ , and Nb 5+ and evaluate the influence of each co-dopant on PEC performance. The PEC characteristic results revealed that Be 2+ and Al 3+ co-dopants enhanced surface charge separation efficiency, thus accelerating charge transfers at the photoanode−electrolyte interface. Meanwhile, the PEC performance of the Hf-HT photoanode co-doped with Nb did not significantly improve because of the thick Nb 2 O 5 overlayer. However, the use of a Si 4+ co-dopant improved the bulk properties of the photoanode. An optimized Hf-HT photoanode co-doped with Be achieved a photocurrent density of 1.98 mA/cm 2 at 1.23 V RHE . This demonstrates that ex situ co-doping can have both positive and negative impacts on the PEC activity of photoelectrodes, and the co-dopants used to accomplish the desired outcomes should be considered in detail.

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“…Also, the dopant created surface-trapping states, causing the ZF2Q photoanode to exhibit an anodic shift in onset potential. 36 Furthermore, the PD of the TiO 2 underlayered TZF2Q photoanodes was substantially superior to that (1.3 mA cm −2 ) of the F2Q photoanode at 1.23 V RHE . The extrinsic Ti 4+ self-diffusion from the TiO 2 underlayer during high-temperature quenching is responsible for this enhanced PD.…”

Section: Resultsmentioning

confidence: 94%

Co-dependency of TiO₂ underlayer and ZrO₂ top layer in sandwiched microwave-assisted Zr-Fe₂O₃ photoanodes for photoelectrochemical water splitting

Hwang¹,

Mahadik²,

Anushkkaran³

et al. 2023

Sustainable Energy Fuels

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Microwave-assisted surface attachment of aluminium ions on in situ diluted titanium-doped hematite photoanodes for efficient photoelectrochemical water-splitting

Abstract: Al/Ti co-doping was performed through an effective microwave-assisted surface attachment method. The synergistic effect of Al/Ti co-doping and an Al2O3 passivation layer significantly boosts the PEC performance in the Al(5 mM)/Ti(4%):Fe2O3 photoanode.

Cited by 9 publications

References 54 publications

Unveiling the Synchronized Effect of Bulk and Surface Dual Modification of In Situ Nb-Doping and Microwave-Assisted Co(OH)_x Cocatalyst for Boosting Photoelectrochemical Water Splitting of Fe₂O₃ Photoanodes

Unveiling the Synchronized Effect of Bulk and Surface Dual Modification of In Situ Nb-Doping and Microwave-Assisted Co(OH)_x Cocatalyst for Boosting Photoelectrochemical Water Splitting of Fe₂O₃ Photoanodes

Unveiling the Significance of Diverse Valence State Second Dopants on Hf-Doped Fe₂O₃ Photoanodes for Enhanced Photoelectrochemical Water Splitting

Co-dependency of TiO₂ underlayer and ZrO₂ top layer in sandwiched microwave-assisted Zr-Fe₂O₃ photoanodes for photoelectrochemical water splitting

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Microwave-assisted surface attachment of aluminium ions on in situ diluted titanium-doped hematite photoanodes for efficient photoelectrochemical water-splitting

Abstract: Al/Ti co-doping was performed through an effective microwave-assisted surface attachment method. The synergistic effect of Al/Ti co-doping and an Al2O3 passivation layer significantly boosts the PEC performance in the Al(5 mM)/Ti(4%):Fe2O3 photoanode.

Cited by 9 publications

References 54 publications

Unveiling the Synchronized Effect of Bulk and Surface Dual Modification of In Situ Nb-Doping and Microwave-Assisted Co(OH)x Cocatalyst for Boosting Photoelectrochemical Water Splitting of Fe2O3 Photoanodes

Unveiling the Synchronized Effect of Bulk and Surface Dual Modification of In Situ Nb-Doping and Microwave-Assisted Co(OH)x Cocatalyst for Boosting Photoelectrochemical Water Splitting of Fe2O3 Photoanodes

Unveiling the Significance of Diverse Valence State Second Dopants on Hf-Doped Fe2O3 Photoanodes for Enhanced Photoelectrochemical Water Splitting

Co-dependency of TiO2 underlayer and ZrO2 top layer in sandwiched microwave-assisted Zr-Fe2O3 photoanodes for photoelectrochemical water splitting

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Unveiling the Synchronized Effect of Bulk and Surface Dual Modification of In Situ Nb-Doping and Microwave-Assisted Co(OH)_x Cocatalyst for Boosting Photoelectrochemical Water Splitting of Fe₂O₃ Photoanodes

Unveiling the Synchronized Effect of Bulk and Surface Dual Modification of In Situ Nb-Doping and Microwave-Assisted Co(OH)_x Cocatalyst for Boosting Photoelectrochemical Water Splitting of Fe₂O₃ Photoanodes

Unveiling the Significance of Diverse Valence State Second Dopants on Hf-Doped Fe₂O₃ Photoanodes for Enhanced Photoelectrochemical Water Splitting

Co-dependency of TiO₂ underlayer and ZrO₂ top layer in sandwiched microwave-assisted Zr-Fe₂O₃ photoanodes for photoelectrochemical water splitting