Uplifting the charge carrier separation and migration in Co-doped CuBi2O4/TiO2 p-n heterojunction photocathode for enhanced photoelectrocatalytic water splitting

Mary, Angelina; Murugan, C.; Pandikumar, Alagarsamy

doi:10.1016/j.jcis.2021.10.172

Cited by 54 publications

(10 citation statements)

References 78 publications

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“…When light falls on the BiVO 4 /CuO electrode, both the BiVO 4 and CuO undergo charge separation. Because of the synergy between the band edge alignment and the IEF, the photogenerated electrons in the CBM of CuO are moved to the CBM of BiVO 4 ; similarly, the holes are moved from the VBM of BiVO 4 to the CuO. ,, Hence, the hole is accumulated in the VBM of CuO and electrons in the CBM of BiVO 4 . At this beneficial condition, the charge carriers are well separated and facilitates sufficient time for water oxidation that ultimately enhances the PEC performance of the p–n junction than the bare-BiVO 4 electrode, and the overall process is shown in Figure c.…”

Section: Resultsmentioning

confidence: 99%

Reinforcement of Visible-Light Harvesting and Charge-Transfer Dynamics of BiVO₄ Photoanode via Formation of p–n Heterojunction with CuO for Efficient Photoelectrocatalytic Water Splitting

Murugan

Pandikumar

2022

ACS Appl. Energy Mater.

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High photoinduced charge recombination process and indolent water oxidation kinetics are major drawbacks of the bismuth vanadate (BiVO4) photoanode in photoelectrocatalytic (PEC) water splitting. To address these issues, a bismuth vanadate/copper oxide (BiVO4/CuO) p–n junction electrode was fabricated via the electrodeposition method, and its PEC performance was studied using 0.1 M potassium phosphate (KPi) as an electrolyte under AM 1.5G (100 mW cm–2) irradiation. At an optimized condition, the BiVO4/CuO p–n junction electrode showed improvement in the current density of 2.05 mA cm–2 at +1.23 VRHE, which was ∼2-fold higher than the BiVO4 electrode (0.99 mA cm–2). The applied bias photon-to-current efficiency (ABPE) of the BiVO4/CuO electrode was also ∼2.5-fold higher than the BiVO4 electrode. Loading of CuO over the BiVO4 surface improved the light absorption ability of the electrode in the entire UV–vis region, leading to generation of a greater number of photoinduced charge carriers, and it also enhanced the reactive sites for water oxidation as per the calculation of double-layer capacitance (C dl). The formation of inner electric field (IEF) at the interface between BiVO4 and CuO offered well-separated electron–hole pairs in association with improvement in the lifetime of charge carriers, and as a consequence, the BiVO4/CuO electrode showed a transient decay time of 4.45 s, which was ∼1.6-fold higher than the BiVO4 electrode (2.81 s). The formation of p–n junction between BiVO4 and CuO significantly reduced the charge transfer resistance (R ct) at the electrode/electrolyte interface (EEI), and as a result, the BiVO4 and BiVO4/CuO electrodes show R ct values of 454.4 and 201.9 Ω, respectively, under light illumination. Moreover, the Bode phase analysis confirmed quick hole consumption in the presence of the BiVO4/CuO electrode over the pristine BiVO4 electrode during water oxidation process. Overall, the formation of a p–n junction facilitated well-separated electron–hole pairs and improved the hole transfer at the EEI for an efficient PEC water oxidation process.

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Section: Resultsmentioning

confidence: 99%

Reinforcement of Visible-Light Harvesting and Charge-Transfer Dynamics of BiVO₄ Photoanode via Formation of p–n Heterojunction with CuO for Efficient Photoelectrocatalytic Water Splitting

Murugan

Pandikumar

2022

ACS Appl. Energy Mater.

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“…The bimetal Mn and Co has a nearly similar range of ionic radius ranges (0.06 to 0.08 A 0 ) which is incorporated into the CuO lattice which does not affect the monoclinic phase; nevertheless, it slightly gets shifted due to the intercalation which occurred in the lattice cell arrangements which make considerable change in the intensification of the crystal size which is noticed in Figure 2(f). The peak shift at the lattice planes of (-111) and (111) slightly corresponds with the 2θ values of 35.4 °for pure CuO shifted into 35.2 °for the doped CuO (Mn and Co) and 38.5 °to 38.6 °for pure and doped CuO, respectively [47].…”

Section: Resultsmentioning

confidence: 62%

Exploration of Bifunctionality in Mn, Co Codoped CuO Nanoflakes for Overall Water Splitting

Rani,

Mohana,

Swathi

et al. 2023

International Journal of Energy Research

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Herein, bimetal (Mn, Co) codoping on a CuO host is aimed at enhancing oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) activity. Codoping of Mn and Co on CuO to enhance bifunctional action in electrochemical water splitting has not yet been investigated to the best of our knowledge. Literatures are focused on unary Mn-doped CuO or Co-doped CuO nanostructures. Mn, Co codoped CuO through an easy chemical coprecipitation method has been successfully attempted and is more beneficial which is the novelty of the present work. Defect-enriched ample active sites (Mn2+/Mn3+ and Co2+/Co3+) along with Cu2+ in the host CuO achieved high current density (100 mA/cm2) in OER and HER with low overpotential such as 468 mV and 271 mV, respectively. Faster charge transfer and diffusion ability was stimulated by the bimetal codoping CuO. Reasonable Tafel plot values (OER: 199 mV/dec, and HER: 21 mV/dec) with improved water-splitting reaction kinetics were achieved for the Mn, Co codoped CuO nanoflakes. The double-layer capacitance ( C dl ) value of 27.5 mF/cm2 for Mn, Co codoped CuO nanoflakes was achieved. Similarly, the increasing order of an electrochemically active surface area (EASA) was exhibited by the consequent addition of bimetal doping on CuO, denoted as Mn , Co / CuO > Co / CuO > Mn / CuO > CuO . The evidence shows that the codoping strategy could facilitate rapid reaction kinetics to develop overall water splitting. The charge transfer resistances ( R ct ) of 3.6 Ω and 1.2 Ω for the Mn, Co codoped CuO nanostructure corresponding to the OER and HER, respectively, were reported. The long-term stability over 16 h with negligible loss was reported for both the OER and the HER performance. Thus, this work contributes to better insight and analysis of the successful codoping of bimetal elements in earth-abundant electrocatalysts to enhance and make practical the electrocatalytic water-splitting activity.

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“…Integrating TiO 2 with narrow bandgap semiconductors to form heterostructures is an excellent approach to strengthen photoactivity and facilitate the development of PEC water splitting. − Heterojunctions are pivotal in expediting efficient e – and h + transfer while concurrently mitigating recombination phenomena. , Several studies have reported the construction of semiconductor-based photocatalysts with other matched semiconductors such as CdS/TiO 2 , − Ni 2 P/TiO 2 , , Co 3 O 4 /TiO 2 , and NiCo–LDH/TiO 2 . Compared with transition metal hydroxides and oxides, transition metal sulfides commonly exhibit a narrower bandgap and a wider range of optical responsiveness .…”

Section: Introductionmentioning

confidence: 99%

“…Zhong et al 17 reported that Nb-doping caused an increase in the electron concentration and a shift in the energy band structure of TiO 2 , thereby resulting in a decrease in the bandgap value. Additionally, Dudziak et al 18 found that using Nb as a donor was advantageous because of its well-defined shallow properties and the ease with which it could be doped into an anatase structure. These results demonstrated that Nb doping is beneficial for improving the overall properties of TiO 2 .…”

Section: Introductionmentioning

confidence: 99%

Constructing Sequential Type II Heterojunction CQDs/Bi₂S₃/TiNbO Photoanode with Superior Charge Transfer Capability Toward Stable Photoelectrochemical Water Splitting

Pan,

Dong,

Qin

et al. 2024

ACS Appl. Mater. Interfaces

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Efficient charge transfer and light-trapping units are pivotal prerequisites in the realm of Ti-based photoanode photoelectrochemical (PEC) water splitting. In this work, we successfully synthesized a ternary carbon quantum dots/Bi 2 S 3 quantum dots/Nb-doped TiO 2 nanotube arrays (CQDs/Bi 2 S 3 /TiNbO) composite photoanode for PEC water splitting. CQDs/Bi 2 S 3 /TiNbO composite photoanode exhibited a considerably elevated photocurrent density of 8.80 mA cm −2 at 1.23 V vs the reversible hydrogen electrode, which was 20.00 times better than that of TiO 2 (0.44 mA cm −2 ). Furthermore, the CQDs/Bi 2 S 3 /TiNbO composite photoanode attested to exceptional stability, maintaining 92.54% of its initial current after 5 h of stability measurement. Nb-doping boosted the electrical conductivity, facilitating charge transfer at the solid−liquid interface. Moderate amounts of Bi 2 S 3 quantum dots (QDs) and CQDs deposited on TiNbO provided abundant active sites for the electrolyte−photoanode interaction. Simultaneously, Bi 2 S 3 QDs and CQDs synergistically functioned as light-trapping units to broaden the light absorption range from 396 to 530 nm, stimulating increased carrier generation within the composite photoanode. In comparison with pristine TiO, CQDs/Bi 2 S 3 /TiNbO photoanodes possessed a superior ability to promote interfacial reactions. This study may provide a strategy for developing highperformance Ti-based photoanodes with efficient charge transfer and light trapping units for highly driving solar-to-hydrogen conversion.

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Uplifting the charge carrier separation and migration in Co-doped CuBi2O4/TiO2 p-n heterojunction photocathode for enhanced photoelectrocatalytic water splitting

Cited by 54 publications

References 78 publications

Reinforcement of Visible-Light Harvesting and Charge-Transfer Dynamics of BiVO₄ Photoanode via Formation of p–n Heterojunction with CuO for Efficient Photoelectrocatalytic Water Splitting

Reinforcement of Visible-Light Harvesting and Charge-Transfer Dynamics of BiVO₄ Photoanode via Formation of p–n Heterojunction with CuO for Efficient Photoelectrocatalytic Water Splitting

Exploration of Bifunctionality in Mn, Co Codoped CuO Nanoflakes for Overall Water Splitting

Constructing Sequential Type II Heterojunction CQDs/Bi₂S₃/TiNbO Photoanode with Superior Charge Transfer Capability Toward Stable Photoelectrochemical Water Splitting

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Uplifting the charge carrier separation and migration in Co-doped CuBi2O4/TiO2 p-n heterojunction photocathode for enhanced photoelectrocatalytic water splitting

Cited by 54 publications

References 78 publications

Reinforcement of Visible-Light Harvesting and Charge-Transfer Dynamics of BiVO4 Photoanode via Formation of p–n Heterojunction with CuO for Efficient Photoelectrocatalytic Water Splitting

Reinforcement of Visible-Light Harvesting and Charge-Transfer Dynamics of BiVO4 Photoanode via Formation of p–n Heterojunction with CuO for Efficient Photoelectrocatalytic Water Splitting

Exploration of Bifunctionality in Mn, Co Codoped CuO Nanoflakes for Overall Water Splitting

Constructing Sequential Type II Heterojunction CQDs/Bi2S3/TiNbO Photoanode with Superior Charge Transfer Capability Toward Stable Photoelectrochemical Water Splitting

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Reinforcement of Visible-Light Harvesting and Charge-Transfer Dynamics of BiVO₄ Photoanode via Formation of p–n Heterojunction with CuO for Efficient Photoelectrocatalytic Water Splitting

Reinforcement of Visible-Light Harvesting and Charge-Transfer Dynamics of BiVO₄ Photoanode via Formation of p–n Heterojunction with CuO for Efficient Photoelectrocatalytic Water Splitting

Constructing Sequential Type II Heterojunction CQDs/Bi₂S₃/TiNbO Photoanode with Superior Charge Transfer Capability Toward Stable Photoelectrochemical Water Splitting