Switching from Two-electron to Four-electron Photocatalytic Pure Water Splitting via Band Bending Engineering with Boosted Activity

Organic dye-sensitised SrTiO3:Rh and WO3 were served as H2 catalysts and O2 catalysts in a Z-scheme system to conduct photocatalytic pure water splitting. To enhance the light absorption capacity, the composites of organic dye (N3, N719, Z907, black dye, C101, and K19) and SrTiO3:Rh were synthesised via physical adsorption and then verified by the performance of photocatalytic hydrogen evolution. Among these dyes, N3-SrTiO3:Rh revealed visible light absorption and exhibited the best photocatalytic activity. Therefore, N3 dye was adopted, and silane coupling agents were used to form chemical bonding with SrTiO3:Rh. Furthermore, the photocatalytic pure water splitting of N3-SrTiO3:Rh was investigated in a single reactor, and a twin photoreactor with Fe2+ and Fe3+ ions served as the electron mediators, respectively. The highest quantum efficiency can reach 0.0259% in a twin reactor when compared with the single reactor (0.0052%) because of the improvement in the light absorption from N3 and inhibition of the backward reaction of water splitting. Consequently, organic dye-sensitised photocatalysts are highly effective and eco-friendly in conducting photocatalytic pure water splitting.

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Silver-Inserted Heterojunction Photocatalysts for Z-Scheme Overall Pure-Water Splitting under Visible-Light Irradiation

The Journal of Physical Chemistry C ◽

10.1021/jp5069973 ◽

2014 ◽

Vol 118 (39) ◽

pp. 22450-22456 ◽

Cited By ~ 50

Author(s):

Ryoya Kobayashi ◽

Satoshi Tanigawa ◽

Toshihiro Takashima ◽

Bunsho Ohtani ◽

Hiroshi Irie

Keyword(s):

Visible Light ◽

Water Splitting ◽

Visible Light Irradiation ◽

Pure Water ◽

Light Irradiation

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Spontaneous full photocatalytic water splitting on 2D MoSe2/SnSe2 and WSe2/SnSe2 vdW heterostructures

Nanoscale ◽

10.1039/c9nr03469b ◽

2019 ◽

Vol 11 (31) ◽

pp. 14836-14843 ◽

Cited By ~ 24

Author(s):

Yingcai Fan ◽

Junru Wang ◽

Mingwen Zhao

Keyword(s):

Energy Conversion ◽

Water Splitting ◽

Pure Water ◽

Photocatalytic Water Splitting ◽

Conversion Efficiencies

The heterostructures have the HER and OER in water-splitting taking place separately on the two components with the STH energy conversion efficiencies up to 10.5%. The Se-vacancy makes the two reactions occur spontaneously in pure water.

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Overall pure water splitting using one-dimensional P-doped twinned Zn0.5Cd0.5S1-x nanorods via synergetic combination of long-range ordered homojunctions and interstitial S vacancies with prolonged carrier lifetime

Applied Catalysis B Environmental ◽

10.1016/j.apcatb.2019.118309 ◽

2020 ◽

Vol 262 ◽

pp. 118309 ◽

Cited By ~ 9

Author(s):

Boon-Junn Ng ◽

Lutfi Kurnianditia Putri ◽

Xin Ying Kong ◽

Pooria Pasbakhsh ◽

Siang-Piao Chai

Keyword(s):

Water Splitting ◽

Long Range ◽

Carrier Lifetime ◽

Pure Water ◽

One Dimensional

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Particulate photocatalyst sheets for Z-scheme water splitting: advantages over powder suspension and photoelectrochemical systems and future challenges

Faraday Discussions ◽

10.1039/c6fd00184j ◽

2017 ◽

Vol 197 ◽

pp. 491-504 ◽

Cited By ~ 23

Author(s):

Qian Wang ◽

Takashi Hisatomi ◽

Masao Katayama ◽

Tsuyoshi Takata ◽

Tsutomu Minegishi ◽

...

Keyword(s):

Water Splitting ◽

Large Scale ◽

Metal Layer ◽

Pure Water ◽

Elevated Pressure ◽

Advantages And Disadvantages ◽

Solar Water Splitting ◽

Close Proximity ◽

Future Challenges ◽

Powder Suspension

Water splitting using semiconductor photocatalysts has been attracting growing interest as a means of solar energy based conversion of water to hydrogen, a clean and renewable fuel. Z-scheme photocatalytic water splitting based on the two-step excitation of an oxygen evolution photocatalyst (OEP) and a hydrogen evolution photocatalyst (HEP) is a promising approach toward the utilisation of visible light. In particular, a photocatalyst sheet system consisting of HEP and OEP particles embedded in a conductive layer has been recently proposed as a new means of obtaining efficient and scalable redox mediator-free Z-scheme solar water splitting. In this paper, we discuss the advantages and disadvantages of the photocatalyst sheet approach compared to conventional photocatalyst powder suspension and photoelectrochemical systems through an examination of the water splitting activity of Z-scheme systems based on SrTiO3:La,Rh as the HEP and BiVO4:Mo as the OEP. This photocatalyst sheet was found to split pure water much more efficiently than the powder suspension and photoelectrochemical systems, because the underlying metal layer efficiently transfers electrons from the OEP to the HEP. The photocatalyst sheet also outperformed a photoelectrochemical parallel cell during pure water splitting. The effects of H+/OH− concentration overpotentials and of the IR drop are reduced in the case of the photocatalyst sheet compared to photoelectrochemical systems, because the HEP and OEP are situated in close proximity to one another. Therefore, the photocatalyst sheet design is well-suited to efficient large-scale applications. Nevertheless, it is also noted that the photocatalytic activity of these sheets drops markedly with increasing background pressure because of reverse reactions involving molecular oxygen under illumination as well as delays in gas bubble desorption. It is shown that appropriate surface modifications allow the photocatalyst sheet to maintain its water splitting activity at elevated pressure. Accordingly, we conclude that the photocatalyst sheet system is a viable option for the realisation of efficient solar fuel production.

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Photocatalytic Water Splitting and Photocatalytic Degradation in Aqueous GdVO4 Suspensions under Simulated Solar Irradiation

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.873.571 ◽

2013 ◽

Vol 873 ◽

pp. 571-574 ◽

Cited By ~ 3

Author(s):

Yan Bai ◽

Ya Ming Ding ◽

Zhi Min Li

Keyword(s):

Photocatalytic Activity ◽

High Temperature ◽

Solid State ◽

Water Splitting ◽

Rhodamine B ◽

Pure Water ◽

Xrd Analysis ◽

Solar Irradiation ◽

Tetragonal Type ◽

Simulated Solar Irradiation

GdVO4 was synthesized by solid state reaction at high temperature and characterized by XRD, UVvisible DRS, BET and SEM. XRD analysis of GdVO4 showed its structure was of tetragonal type. When GdVO4 was loaded with 0.3 wt% Pt, it showed the better photocatalytic activity for water splitting under simulated solar irradiation, and the amounts of the produced hydrogen in pure water were about 9.33 μmol under the irradiation of simulated solar for 6 h. Furthermore, photodegradation of Rhodamine B (Rh B ) on the samples were investigated under simulated solar irradiation.

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Overall water splitting by Pt/g-C3N4photocatalysts without using sacrificial agents

Chemical Science ◽

10.1039/c5sc04572j ◽

2016 ◽

Vol 7 (5) ◽

pp. 3062-3066 ◽

Cited By ~ 535

Author(s):

Guigang Zhang ◽

Zhi-An Lan ◽

Lihua Lin ◽

Sen Lin ◽

Xinchen Wang

Keyword(s):

Conjugated Polymers ◽

Water Splitting ◽

Pure Water ◽

Molar Ratio ◽

Co Catalysts ◽

Overall Water Splitting ◽

First Time

Direct splitting of pure water into H2and O2in a stoichiometric molar ratio of 2 : 1 by conjugated polymersviaa 4-electron pathway was established for the first time, as demonstrated here using a g-C3N4polymer and redox co-catalysts of Pt and Co species.

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Sb2S3/TiO2 Heterojunction Photocathodes: Band Alignment and Water Splitting Properties

10.26434/chemrxiv.12110208 ◽

2020 ◽

Author(s):

Rajiv Ramanujam Prabhakar ◽

Thomas Moehl ◽

Sebastian Siol ◽

Jihye Suh ◽

David Tilley

Keyword(s):

Buffer Layer ◽

Water Splitting ◽

Elemental Sulfur ◽

Band Alignment ◽

Band Bending ◽

Co Catalyst ◽

Conduction Band Offset ◽

Photovoltaic Applications ◽

Earth Abundant ◽

Further Development

Antimony sulfide (Sb2S3) is a promising light absorbing semiconductor for photovoltaic applications, though it remains vastly unexplored for photoelectrochemical water splitting. Sb2S3 was synthesized by a simple sulfurization of electrodeposited antimony metal at relatively low temperatures (240-300°C) with elemental sulfur. Using a TiO2 buffer layer and a platinum co-catalyst, photocurrent densities up to ~ 9 mA cm-2 were achieved at -0.4 V vs. RHE in 1 M H2SO4 under one sun illumination. Using XPS band alignment studies and potential dependent IPCE measurements, a conduction band offset of 0.7 eV was obtained for the Sb2S3/TiO2 junction as well as an unfavorable band bending at the heterointerface, which explains the low photovoltage that was observed (~ 0.1 V). Upon inserting an In2S3 buffer layer, which offers a better band alignment, a 0.15 V increase in photovoltage was obtained. The excellent PEC performance and the identification of the origin of the low photovoltage of the Sb2S3 photocathodes in this work pave the way for the further development of this promising earth abundant light absorbing semiconductor for solar fuels generation.

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