Efficient hydrogen evolution from water using CdTe photocathodes under simulated sunlight

2017 ◽  
Vol 5 (25) ◽  
pp. 13154-13160 ◽  
Author(s):  
Jin Su ◽  
Tsutomu Minegishi ◽  
Kazunari Domen
Keyword(s):  
Hydrogen Evolution ◽  
Conversion Efficiency ◽  
Simulated Sunlight ◽  
Applied Potential ◽  
Incident Photon

CdTe-based photocathodes have shown an extremely high incident photon-to-current conversion efficiency (IPCEs) of >95% at 560–660 nm with an applied potential of 0 VRHE.

Photoelectrochemical Properties of Surface-Modified ZnSe:Cu(In,Ga)Se2 Photocathodes for Efficient and Durable Overall Water Splitting

2018 ◽  
Vol MA2018-01 (31) ◽  
pp. 1922-1922
Author(s):  
Hiroyuki Kaneko ◽  
Tsutomu Minegishi ◽  
Kazunari Domen
Keyword(s):  
Hydrogen Evolution ◽  
Water Splitting ◽  
Phosphate Buffer Solution ◽  
Potassium Phosphate ◽  
List Type ◽  
Simulated Sunlight ◽  
Current Time ◽  
Overall Water Splitting ◽  
Potassium Phosphate Buffer Solution ◽  
Surface Modified

Overall water splitting using a photoelectrochemical (PEC) cell composed of a photocathode and photoanode connected in a series is an attractive method to produce hydrogen from water under sunlight. Because driving forces of two photoelectrodes are combined for the water splitting reaction, narrow-gap materials can be used to achieve high solar-to-hydrogen conversion efficiency (STH). However, the STHs obtained from a PEC cell without any external bias voltage reported so far have been less than 1%. This is because of insufficient onset potentials and photocurrent values of photoelectrodes. For the sake of overcoming the drawbacks, (ZnSe)0.85(CuIn0.7Ga0.3Se2)0.15 ((ZnSe)0.85(CIGS)0.15) thin film photocathodes have recently been developed and reported to show a high onset potential of 0.89 VRHE and long absorption edge of 850-900 nm.2 These properties are suitable for use in the PEC cell. (ZnSe)0.85(CIGS)0.15 thin films are prepared by co-evaporation onto Mo-coated soda-lime glass substrates. Subsequently, CdS, a binary of Mo/Ti and Pt are deposited onto the photocathode surface as a buffer layer, surface conductor and hydrogen evolution reaction (HER) catalyst, respectively.3 The surface-modified (ZnSe)0.85(CIGS)0.15 photocathodes show a relatively high photocurrent value of 12 mA cm-2 at 0 VRHE and sufficient stability in a span of hours at potentials of more negative than 0.5 VRHE under simulated sunlight in a neutral potassium phosphate buffer solution.4 However, at potentials more positive than 0.5 VRHE, the photocurrent value attributed to HER dramatically decreases by half in just one hour mainly due to self-oxidation of the surface sulfide layer, accompanying detachment of the Mo/Ti and Pt at the surface. The poor stability at the positive potentials has made it difficult to construct durable PEC cell using the photocathodes. In this work, effects of surface modifications onto PEC properties of (ZnSe)0.85(CIGS)0.15 photocathodes are investigated. For the sake of suppressing the surface corrosion, the CdS layer was passivated with In2S3, which was formed by using chemical bath deposition (CBD).5 Figure 1 shows the current-time curves of the surface-modified (ZnSe)0.85(CIGS)0.15 photocathodes at 0.6 VRHE under simulated sunlight. Without the CBD treatment, the photocurrent value decreased by 50% in one hour under light irradiation. On the other hand, the In2S3-modified photocathode showed relatively stable PEC HER and the decline of the photocurrent value in one hour was decreased to 25%. It is highly possible that the improvement of stability originates from low solubility of indium oxide or hydroxide generated by the self-oxidation process, while the cadmium oxide and hydroxide are relatively soluble, which can cause corrosion of the surface. Furthermore, effects of oxide-coating onto the stability of the (ZnSe)0.85(CIGS)0.15 photocathode during PEC hydrogen evolution have also been investigated. Among various kinds of coating processes, direct formation of the oxide layer by photoelectrodeposition without annealing the photocathode is an effective method without exerting a bad influence on the underlying sulfide and selenide materials. In the presentation, the details of preparation conditions and PEC properties will be discussed. References J. W. Ager, M. R. Shaner, K. A. Walczak, I. D. Sharp and S. Ardo, Energy Environ. Sci. 2015, 8, 2811–2824. H. Kaneko, T. Minegishi, M. Nakabayashi, N. Shibata, Y. Kuang, T. Yamada and K. Domen, Adv. Funct. Mater. 2016, 26, 4570–4577. H. Kumagai, T. Minegishi, N. Sato, T. Yamada, J. Kubota and K. Domen, J. Mater. Chem. A 2015, 3, 8300–8307. H. Kaneko, T. Minegishi, M. Nakabayashi, N. Shibata and K. Domen, Angew. Chemie Int. Ed. 2016, 55, 15329–15333. F. Jiang, Gunawan, T. Harada, Y. Kuang, T. Minegishi, K. Domen and S. Ikeda, J. Am. Chem. Soc. 2015, 137, 13691–13697. Figure 1

scholarly journals Simple Environmentally-Friendly Reduction of 4-Nitrophenol

Catalysts ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 458 ◽  
Author(s):  
Albert Serrà ◽  
Raül Artal ◽  
Maria Pozo ◽  
Jaume Garcia-Amorós ◽  
Elvira Gómez
Keyword(s):  
Electrochemical Reduction ◽  
Hydrogen Evolution ◽  
Chemical Processes ◽  
Operating Conditions ◽  
Chemical Degradation ◽  
Applied Potential ◽  
Acidic Media ◽  
Nitrophenol Reduction ◽  
Aromatic Species ◽  
By Products

The low molecular-mass organic compound 4-nitrophenol is involved in many chemical processes and is commonly present in soils and in surface and ground waters, thereby causing severe environmental impact and health risk. Several methods have been proposed for its transformation (bio and chemical degradation). However, these strategies not only produce equally or more toxic aromatic species but also require harsh operating conditions and/or time-consuming treatments. In this context, we report a comprehensive and systematic study of the electrochemical reduction of 4-nitrophenol as a viable alternative. We have explored the electrochemical reduction of this pollutant over different metallic and carbonaceous substrata. Specifically, we have focused on the use of gold and silver working electrodes since they combine a high electrocatalytic activity for 4-nitrophenol reduction and a low electrocatalytic capacity for hydrogen evolution. The influence of the pH, temperature, and applied potential have also been considered as crucial parameters in the overall optimization of the process. While acidic media and high temperatures favor the clean reduction of 4-nitrophenol to 4-aminophenol, the simultaneous hydrogen evolution is pernicious for this purpose. Herein, a simple and effective electrochemical method for the transformation of 4-nitrophenol into 4-aminophenol is proposed with virtually no undesired by-products.

scholarly journals Structural Effects on the Incident Photon-to-Current Conversion Efficiency of Zn Porphyrin Dyes on the Low-Index Planes of TiO2

ACS Omega ◽  
2017 ◽  
Vol 2 (1) ◽  
pp. 128-135 ◽  
Author(s):  
Ryo Ide ◽  
Yamato Fujimori ◽  
Yukihiro Tsuji ◽  
Tomohiro Higashino ◽  
Hiroshi Imahori ◽  
...  
Keyword(s):  
Conversion Efficiency ◽  
Structural Effects ◽  
Incident Photon

Hybrid Solar Cells From Silicon Nanocrystals and Conductive Polymers

2009 ◽  
Author(s):  
Chin-Yi Liu ◽  
Uwe R. Kortshagen
Keyword(s):  
Solar Cells ◽  
Power Conversion Efficiency ◽  
Conversion Efficiency ◽  
Conjugated Polymer ◽  
Silicon Nanocrystals ◽  
Conductive Polymers ◽  
Power Conversion ◽  
Hybrid Solar Cells ◽  
Incident Photon ◽  
Direct Illumination

Hybrid solar cells based on blends of a conjugated polymer, poly-3(hexylthiophene) (P3HT), and silicon nanocrystals (Si NCs) have been developed and characterized. The properties of composite Si NCs/P3HT films which were spun from 1, 2-dichlorobenzene were studied. Under A.M. 1.5 direct illumination conditions (100mW/cm2), devices made with 50wt% 3–5nm Si NCs showed 1.33% power conversion efficiency (PCE) and had a 30% incident-photon-to-current conversion efficiency at 470 nm.

An energy band compactable B-rGO/PbTiO3 p–n junction: a highly dynamic and durable photocatalyst for enhanced photocatalytic H2 evolution

Nanoscale ◽  
2019 ◽  
Vol 11 (46) ◽  
pp. 22328-22342 ◽  
Author(s):  
Lekha Paramanik ◽  
K. Hemalata Reddy ◽  
K. M. Parida
Keyword(s):  
Energy Conversion ◽  
Hydrogen Evolution ◽  
Conversion Efficiency ◽  
Energy Band ◽  
Energy Conversion Efficiency ◽  
H2 Evolution ◽  
Photocatalytic H2 Evolution

Efficient hydrogen evolution is achieved over a B-rGO/PbTiO3 p–n heterojunction with an energy conversion efficiency of 19.28%.

scholarly journals Bismuth Oxysulfide Photoelectrodes with Giant Incident Photon‐to‐Current Conversion Efficiency: Chemical Stability in Aqueous Solutions

2019 ◽  
Vol 6 (9) ◽  
pp. 2474-2481
Author(s):  
Evgeny A. Bondarenko ◽  
Eugene A. Streltsov ◽  
Alexander V. Mazanik ◽  
Anatoly I. Kulak
Keyword(s):  
Aqueous Solutions ◽  
Conversion Efficiency ◽  
Chemical Stability ◽  
Incident Photon

scholarly journals Durable hydrogen evolution from water driven by sunlight using (Ag,Cu)GaSe2 photocathodes modified with CdS and CuGa3Se5

2015 ◽  
Vol 6 (2) ◽  
pp. 894-901 ◽  
Author(s):  
Li Zhang ◽  
Tsutomu Minegishi ◽  
Mamiko Nakabayashi ◽  
Yohichi Suzuki ◽  
Kazuhiko Seki ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Multilayer Structure ◽  
Simulated Sunlight

The multilayer structure enhances the hydrogen evolution from water under simulated sunlight.

Ultrathin HNbWO6 nanosheets: facile synthesis and enhanced hydrogen evolution performance from photocatalytic water splitting

2015 ◽  
Vol 51 (82) ◽  
pp. 15125-15128 ◽  
Author(s):  
Yuhao Liu ◽  
Jinhua Xiong ◽  
Shuiguang Luo ◽  
Ruowen Liang ◽  
Na Qin ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Water Splitting ◽  
Simulated Sunlight ◽  
Facile Synthesis ◽  
Sunlight Irradiation ◽  
Photocatalytic Water Splitting ◽  
Highly Dispersed

Ultrathin monolayer HNbWO6 nanosheets were rapidly synthesised with triethanolamine as a stripping agent in just a few minutes. These obtained highly dispersed nanosheets suspensions exhibit an efficient photocatalytic H2 evolution performance under simulated sunlight irradiation.

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