scholarly journals Surface Modification of Hematite Photoanodes for Improvement of Photoelectrochemical Performance

Catalysts ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 497 ◽  
Author(s):  
Lifei Xi ◽  
Kathrin Lange
Keyword(s):  
Surface Modification ◽  
Water Splitting ◽  
Oxygen Evolution ◽  
Water Oxidation ◽  
Oxidation Kinetics ◽  
Surface Passivation ◽  
Earth Metal ◽  
Photoelectrochemical Performance ◽  
Onset Potential ◽  
Solar Water Splitting

Solar water splitting is a promising method for producing renewable fuels. Thermodynamically, the overall water splitting reaction is an uphill reaction involving a multiple electron transfer process. The oxygen evolution reaction (OER) has been identified as the bottleneck process. Hematite (α-Fe2O3) is one of the best photoanode material candidates due to its band gap properties and stability in aqueous solution. However, the reported efficiencies of hematite are notoriously lower than the theoretically predicted value mainly due to poor charge transfer and separation ability, short hole diffusion length as well as slow water oxidation kinetics. In this Review Article, several emerging surface modification strategies to reduce the oxygen evolution overpotential and thus to enhance the water oxidation reaction kinetics will be presented. These strategies include co-catalysts loading, photoabsorption enhancing (surface plasmonic metal and rare earth metal decoration), surface passivation layer deposition, surface chemical etching and surface doping. These methods are found to reduce charge recombination happening at surface trapping states, promote charge separation and diffusion, and accelerate water oxidation kinetics. The detailed surface modification methods, surface layer materials, the photoelectrochemical (PEC) performances including photocurrent and onset potential shift as well as the related proposed mechanisms will be reviewed.

Two photon tandem photoanode with black phosphorous quantum dot sensitized BiVO4 for solar water splitting

2022 ◽  
Author(s):  
Bingjun Jin ◽  
Yoonjun Cho ◽  
Cheolwoo Park ◽  
Jeehun Jeong ◽  
Sungsoon Kim ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Water Splitting ◽  
Water Oxidation ◽  
Oxidation Kinetics ◽  
Light Harvesting ◽  
Charge Recombination ◽  
Solar Water ◽  
Two Photon ◽  
Solar Water Splitting ◽  
Pec Water Splitting

The photoelectrochemical (PEC) water splitting efficiency is profoundly restricted by the limited light harvesting, rapid charge recombination, and sluggish water oxidation kinetics, in which the construction of a photoelectrode requires...

Tunable surface modification of a hematite photoanode by a Co(salen)-based cocatalyst for boosting photoelectrochemical performance

2020 ◽  
Vol 10 (6) ◽  
pp. 1714-1723
Author(s):  
Ruiling Wang ◽  
Yasutaka Kuwahara ◽  
Kohsuke Mori ◽  
Yuyu Bu ◽  
Hiromi Yamashita
Keyword(s):  
Surface Modification ◽  
Water Splitting ◽  
Oxygen Evolution ◽  
Photoelectrochemical Performance

A water splitting photoanode composed of hematite (α-Fe2O3) nanorods modified with Co(salen) was proven to exhibit special photoelectrochemical oxygen evolution activity.

scholarly journals NiFeOx decorated Ge-hematite/perovskite for an efficient water splitting system

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ki-Yong Yoon ◽  
Juhyung Park ◽  
Minsu Jung ◽  
Sang-Geun Ji ◽  
Hosik Lee ◽  
...  
Keyword(s):  
Water Splitting ◽  
Water Oxidation ◽  
Photocurrent Density ◽  
Photoelectrochemical Performance ◽  
Co Doping ◽  
Solar Water Splitting ◽  
Oxidation Performance ◽  
Oxide Substrate ◽  
Splitting System ◽  
Co Doped

AbstractTo boost the photoelectrochemical water oxidation performance of hematite photoanodes, high temperature annealing has been widely applied to enhance crystallinity, to improve the interface between the hematite-substrate interface, and to introduce tin-dopants from the substrate. However, when using additional dopants, the interaction between the unintentional tin and intentional dopant is poorly understood. Here, using germanium, we investigate how tin diffusion affects overall photoelectrochemical performance in germanium:tin co-doped systems. After revealing that germanium is a better dopant than tin, we develop a facile germanium-doping method which suppresses tin diffusion from the fluorine doped tin oxide substrate, significantly improving hematite performance. The NiFeOx@Ge-PH photoanode shows a photocurrent density of 4.6 mA cm−2 at 1.23 VRHE with a low turn-on voltage. After combining with a perovskite solar cell, our tandem system achieves 4.8% solar-to-hydrogen conversion efficiency (3.9 mA cm−2 in NiFeOx@Ge-PH/perovskite solar water splitting system). Our work provides important insights on a promising diagnostic tool for future co-doping system design.

scholarly journals TiO2 Nanotubes for Solar Water Splitting: Vacuum Annealing and Zr Doping Enhance Water Oxidation Kinetics

ACS Omega ◽  
2019 ◽  
Vol 4 (14) ◽  
pp. 16095-16102 ◽  
Author(s):  
Maged N. Shaddad ◽  
Drialys Cardenas-Morcoso ◽  
Miguel García-Tecedor ◽  
Francisco Fabregat-Santiago ◽  
Juan Bisquert ◽  
...  
Keyword(s):  
Water Splitting ◽  
Water Oxidation ◽  
Oxidation Kinetics ◽  
Tio2 Nanotubes ◽  
Vacuum Annealing ◽  
Solar Water ◽  
Solar Water Splitting

scholarly journals The rise of hematite: origin and strategies to reduce the high onset potential for the oxygen evolution reaction

2015 ◽  
Vol 3 (33) ◽  
pp. 16896-16912 ◽  
Author(s):  
Beniamino Iandolo ◽  
Björn Wickman ◽  
Igor Zorić ◽  
Anders Hellman
Keyword(s):  
Water Splitting ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Water Oxidation ◽  
Large Scale ◽  
Electrochemical Potential ◽  
Onset Potential

The prospect of large scale light-driven water splitting on hematite (Fe2O3) is currently hampered by the high electrochemical potential required to initiate the water oxidation.

Synergistic effects of P-doping and a MnO2 cocatalyst on Fe2O3 nanorod photoanodes for efficient solar water splitting

2018 ◽  
Vol 6 (16) ◽  
pp. 7021-7026 ◽  
Author(s):  
Qiang Rui ◽  
Lei Wang ◽  
Yajun Zhang ◽  
Chenchen Feng ◽  
Beibei Zhang ◽  
...  
Keyword(s):  
Water Splitting ◽  
Oxygen Evolution ◽  
Water Oxidation ◽  
Synergistic Effects ◽  
Oxidation Activity ◽  
Solar Water ◽  
Solar Water Splitting

Herein, we demonstrate that Fe2O3 nanorod photoanodes modified with P-doping and a MnO2 oxygen evolution cocatalyst exhibited a remarkably enhanced PEC water oxidation activity.

A highly enhanced photoelectrochemical performance of BiVO4 photoanodes modified with CoPi groups by increasing energy band bending, accelerating hole separation and improving water oxidation kinetics

2022 ◽  
Author(s):  
Wanqing Fang ◽  
Ai Qin ◽  
Yimin Lin ◽  
Rongzi Xv ◽  
Li Fu
Keyword(s):  
Water Splitting ◽  
Water Oxidation ◽  
Oxidation Kinetics ◽  
Energy Band ◽  
Chemical Characterization ◽  
Photoelectrochemical Performance ◽  
Band Bending ◽  
Physical And Chemical Characterization ◽  
Energy Band Bending ◽  
Physical And Chemical

BiVO4 is one of the most attractive photoanode materials for photoelectrochemical water splitting. Herein, cobalt phosphate (CoPi) modified BiVO4 (BiVO4/CoPi) photoanode is prepared by electrodeposition. The physical and chemical characterization...

scholarly journals Correlating flat band and onset potentials for solar water splitting on model hematite photoanodes

RSC Advances ◽  
2015 ◽  
Vol 5 (75) ◽  
pp. 61021-61030 ◽  
Author(s):  
Beniamino Iandolo ◽  
Haixiang Zhang ◽  
Björn Wickman ◽  
Igor Zorić ◽  
Gavin Conibeer ◽  
...  
Keyword(s):  
Grain Boundaries ◽  
Water Splitting ◽  
Water Oxidation ◽  
Oxidation Time ◽  
Flat Band ◽  
Flat Band Potential ◽  
Onset Potential ◽  
Solar Water ◽  
Solar Water Splitting

Increasing oxidation time during fabrication of hematite (Fe2O3) films reduces the amount of grain boundaries, resulting in lower flat band potential and onset potential for water oxidation.

scholarly journals Surface-Modified Ta3N5 Photoanodes for Sunlight-Driven Overall Water Splitting by Photoelectrochemical Cells

Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 584
Author(s):  
Tomohiro Higashi ◽  
Yutaka Sasaki ◽  
Yudai Kawase ◽  
Hiroshi Nishiyama ◽  
Masao Katayama ◽  
...  
Keyword(s):  
Surface Modification ◽  
Water Splitting ◽  
Energy Conversion Efficiency ◽  
Hydrogen Energy ◽  
Back Side ◽  
Onset Potential ◽  
Oxygen Generation ◽  
Solar Water Splitting ◽  
External Bias ◽  
Surface Modified

The development of visible-light-responsive semiconductor-based photoelectrodes is a prerequisite for the construction of efficient photoelectrochemical (PEC) cells for solar water splitting. Surface modification with an electrocatalyst on the photoelectrode is effective for maximizing the water splitting efficiency of the PEC cell. Herein, we investigate the effects of surface modification of Ta3N5 photoanodes with electrocatalysts consisting of Ni, Fe, and Co oxides, and their mixture, on the PEC oxygen evolution reaction (OER) performance. Among the investigated samples, NiFeOx-modified Ta3N5 (NiFeOx/Ta3N5) photoanodes showed the lowest onset potential for OER. A PEC cell with a parallel configuration consisting of a NiFeOx/Ta3N5 photoanode and an Al-doped La5Ti2Cu0.9Ag0.1S5O7 (LTCA:Al) photocathode exhibited stoichiometric hydrogen and oxygen generation from water splitting, without any external bias voltage. The solar-to-hydrogen energy conversion efficiency (STH) of this cell for water splitting was found to be 0.2% at 1 min after the start of the reaction. In addition, water splitting by a PEC cell with a tandem configuration incorporating a NiFeOx/Ta3N5 transparent photoanode prepared on a quartz insulating substrate as a front-side electrode and a LTCA:Al photocathode as a back side electrode was demonstrated, and the STH was found to be 0.04% at the initial stage of the reaction.

scholarly journals Wittichenite semiconductor of Cu3BiS3 films for efficient hydrogen evolution from solar driven photoelectrochemical water splitting

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Dingwang Huang ◽  
Lintao Li ◽  
Kang Wang ◽  
Yan Li ◽  
Kuang Feng ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Water Splitting ◽  
Low Cost ◽  
Solar Hydrogen ◽  
Onset Potential ◽  
Term Stability ◽  
Long Term Stability ◽  
Solar Water Splitting ◽  
Current Densities

AbstractA highly efficient, low-cost and environmentally friendly photocathode with long-term stability is the goal of practical solar hydrogen evolution applications. Here, we found that the Cu3BiS3 film-based photocathode meets the abovementioned requirements. The Cu3BiS3-based photocathode presents a remarkable onset potential over 0.9 VRHE with excellent photoelectrochemical current densities (~7 mA/cm2 under 0 VRHE) and appreciable 10-hour long-term stability in neutral water solutions. This high onset potential of the Cu3BiS3-based photocathode directly results in a good unbiased operating photocurrent of ~1.6 mA/cm2 assisted by the BiVO4 photoanode. A tandem device of Cu3BiS3-BiVO4 with an unbiased solar-to-hydrogen conversion efficiency of 2.04% is presented. This tandem device also presents high stability over 20 hours. Ultimately, a 5 × 5 cm2 large Cu3BiS3-BiVO4 tandem device module is fabricated for standalone overall solar water splitting with a long-term stability of 60 hours.

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