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

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.

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Surface Modification of Hematite Photoanodes for Improvement of Photoelectrochemical Performance

Catalysts ◽

10.3390/catal8110497 ◽

2018 ◽

Vol 8 (11) ◽

pp. 497 ◽

Cited By ~ 12

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.

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Experimental study on the effects of light intensity on energy conversion efficiency of photo-thermo chemical synergetic catalytic water splitting

Thermal Science ◽

10.2298/tsci170626056z ◽

2018 ◽

Vol 22 (Suppl. 2) ◽

pp. 709-718

Author(s):

Ziming Cheng ◽

Ruitian Yu ◽

Fuqiang Wang ◽

Huaxu Liang ◽

Bo Lin ◽

...

Keyword(s):

Hydrogen Production ◽

Light Intensity ◽

Energy Conversion ◽

Water Splitting ◽

Energy Conversion Efficiency ◽

Hydrogen Energy ◽

Optical Losses ◽

Full Spectrum ◽

Solar Water ◽

Solar Water Splitting

Hydrogen production from water using a catalyst and solar energy was an ideal future fuel source. In this study, an elaborate experimental test rig of hydrogen production from solar water splitting was designed and established with self- controlled temperature system. The effects of light intensity on the reaction rate of hydrogen production from solar water splitting were experimentally investigated with the consideration of optical losses, reaction temperature, and photocatalysts powder cluster. Besides, a revised expression of full-spectrum solar-to-hydrogen energy conversion efficiency with the consideration of optical losses was also put forward, which can be more accurate to evaluate the full-spectrum solar-to-hydrogen energy of photo-catalysts powders. The results indicated that optical losses of solar water splitting reactor increased with the increase of the incoming light intensity, and the hydrogen production rate increased linearly with the increase of effective light intensity even at higher light intensity region when the optical losses of solar water splitting reactor were considered.

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

Nature Communications ◽

10.1038/s41467-021-24060-5 ◽

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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Sequential cocatalyst decoration on BaTaO2N towards highly-active Z-scheme water splitting

Nature Communications ◽

10.1038/s41467-021-21284-3 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Zheng Wang ◽

Ying Luo ◽

Takashi Hisatomi ◽

Junie Jhon M. Vequizo ◽

Sayaka Suzuki ◽

...

Keyword(s):

Energy Conversion ◽

Water Splitting ◽

Energy Conversion Efficiency ◽

Hydrogen Energy ◽

Apparent Quantum Yield ◽

Intimate Contact ◽

Single Crystalline ◽

Highly Active ◽

Uniform Dispersion ◽

Solar Hydrogen Production

AbstractOxynitride photocatalysts hold promise for renewable solar hydrogen production via water splitting owing to their intense visible light absorption. Cocatalyst loading is essential for activation of such oxynitride photocatalysts. However, cocatalyst nanoparticles form aggregates and exhibit weak interaction with photocatalysts, which prevents eliciting their intrinsic photocatalytic performance. Here, we demonstrate efficient utilization of photoexcited electrons in a single-crystalline particulate BaTaO2N photocatalyst prepared with the assistance of RbCl flux for H2 evolution reactions via sequential decoration of Pt cocatalyst by impregnation-reduction followed by site-selective photodeposition. The Pt-loaded BaTaO2N photocatalyst evolves H2 over 100 times more efficiently than before, with an apparent quantum yield of 6.8% at the wavelength of 420 nm, from a methanol aqueous solution, and a solar-to-hydrogen energy conversion efficiency of 0.24% in Z-scheme water splitting. Enabling uniform dispersion and intimate contact of cocatalyst nanoparticles on single-crystalline narrow-bandgap particulate photocatalysts is a key to efficient solar-to-chemical energy conversion.

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Insight into the influence of high temperature annealing on the onset potential of Ti-doped hematite photoanodes for solar water splitting

Chinese Chemical Letters ◽

10.1016/j.cclet.2018.01.022 ◽

2018 ◽

Vol 29 (6) ◽

pp. 791-794 ◽

Cited By ~ 2

Author(s):

Yaodong Zhu ◽

Qinfeng Qian ◽

Guozheng Fan ◽

Zhili Zhu ◽

Xin Wang ◽

...

Keyword(s):

High Temperature ◽

Water Splitting ◽

High Temperature Annealing ◽

Onset Potential ◽

Solar Water ◽

Solar Water Splitting ◽

Insight Into

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(Invited) Surface Modification of Dye-Sensitized Hydrogen-Evolving Photocatalyst for Z-Scheme Solar Water Splitting

ECS Meeting Abstracts ◽

10.1149/ma2021-0115696mtgabs ◽

2021 ◽

Vol MA2021-01 (15) ◽

pp. 696-696

Author(s):

Atsushi Kobayashi ◽

Nobutaka Yoshimura ◽

Masaki Yoshida ◽

Masako Kato

Keyword(s):

Surface Modification ◽

Water Splitting ◽

Solar Water ◽

Solar Water Splitting ◽

Dye Sensitized

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Surface-Modified Titanium Dioxide Nanofibers with Gold Nanoparticles for Enhanced Photoelectrochemical Water Splitting

Catalysts ◽

10.3390/catal10020261 ◽

2020 ◽

Vol 10 (2) ◽

pp. 261 ◽

Cited By ~ 2

Author(s):

Van Nghia Nguyen ◽

Minh Vuong Nguyen ◽

Thi Hong Trang Nguyen ◽

Minh Thuy Doan ◽

Loan Le Thi Ngoc ◽

...

Keyword(s):

Electron Microscopy ◽

Gold Nanoparticles ◽

Titanium Dioxide ◽

Water Splitting ◽

Xenon Lamp ◽

Hydrogen Energy ◽

Au Nps ◽

X Ray ◽

Tio2 Nanofiber ◽

Surface Modified

High-stability, high-efficiency, and low-cost solar photoelectrochemical (PEC) water splitting has great potential for hydrogen-energy applications. Here, we report on gold/titanium dioxide (Au/TiO2) nanofiber structures grown directly on a conductive indium tin oxide substrate, and used as photoelectrodes in PEC cells for hydrogen generation. The titanium dioxide nanofibers (TiO2 NFs) are synthesized using electrospinning, and are surface-modified by the deposition of gold nanoparticles (Au NPs) using a simple photoreduction method. The structure and morphology of the materials were characterized by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The surface plasmon resonance (SPR) of the Au NPs was investigated by ultraviolet-visible (UV-Vis) diffuse reflectance spectroscopy. The PEC properties of the as-prepared photoelectrodes were measured. The obtained photoconversion efficiency of 0.52% under simulated-sunlight illumination by a 150 W xenon lamp of the Au/TiO2 NFs structure with 15 min UV irradiation for Au NP deposition was the highest value from comparable structures. Working photoelectrode stability was tested, and the mechanism of the enhanced PEC performance is discussed.

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