Improved Efficiency and Stability of Cadmium Chalcogenide Nanoparticles by Photodeposition of Co-Catalysts

MRS Advances ◽  
2016 ◽  
Vol 1 (59) ◽  
pp. 3923-3927
Author(s):  
Philip Kalisman ◽  
Lilac Amirav
Keyword(s):  
Water Splitting ◽  
Visible Spectrum ◽  
Molar Absorptivity ◽  
Energy Bands ◽  
Co Catalyst ◽  
Photocatalytic Water Splitting ◽  
Co Catalysts ◽  
Production Of Hydrogen ◽  
Cadmium Chalcogenide ◽  
Cadmium Selenide Quantum Dots

ABSTRACTThe production of hydrogen by photocatalytic water splitting is a potentially clean and renewable source for hydrogen fuel. Cadmium chalcogenides are attractive photocatalysts because they have the potential to convert water into hydrogen and oxygen using photons in the visible spectrum. Cadmium sulfide rods with embedded cadmium selenide quantum dots (CdSe@CdS) are particularly attractive because of their high molar absorptivity in the UV-blue spectral region, and their energy bands can be tuned; however, two crucial drawbacks hinder the implementation of these materials in wide spread use: poor charge transfer and photochemical instability.Utilizing photochemical deposition of co-catalysts onto CdSe@CdS substrates we can address each of these weaknesses. We report how novel co-catalyst morphologies can greatly increase efficiency for the water reduction half-reaction. We also report photostability for CdSe@CdS under high intensity 455nm light (a wavelength at which photocatalytic water splitting by CdSe@CdS is possible) by growing metal oxide co-catalysts on the surface of our rods.

scholarly journals Unraveling the synergy between metal–organic frameworks and co-catalysts in photocatalytic water splitting

2020 ◽  
Vol 8 (39) ◽  
pp. 20493-20502
Author(s):  
Stefano Falletta ◽  
Patrick Gono ◽  
Zhendong Guo ◽  
Stavroula Kampouri ◽  
Kyriakos C. Stylianou ◽  
...  
Keyword(s):  
Water Splitting ◽  
Photocatalytic Performance ◽  
Metal Organic Frameworks ◽  
Water Systems ◽  
Band Alignment ◽  
Co Catalyst ◽  
Photocatalytic Water Splitting ◽  
Co Catalysts ◽  
Metal Organic

Theoretical methodologies for the band alignment at MOF/co-catalyst/water systems revealing the electronic and atomistic mechanisms underlying their photocatalytic performance.

scholarly journals Photocatalytic overall water splitting under visible light enabled by a particulate conjugated polymer loaded with iridium

2022 ◽  
Author(s):  
Yang Bai ◽  
Chao Li ◽  
Lunjie Liu ◽  
Yuichi Yamaguchi ◽  
Bahri Mounib ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Water Splitting ◽  
Conjugated Polymer ◽  
Hydrogen Energy ◽  
Organic Polymers ◽  
Co Catalyst ◽  
Co Catalysts ◽  
Solar Water Splitting ◽  
Overall Water Splitting ◽  
Production Of Hydrogen

The production of hydrogen from water via solar water splitting is a potential method to overcome the intermittency of the Sun’s energy by storing it as a chemical fuel. Inorganic semiconductors have been studied extensively as photocatalysts for overall water splitting, but polymer photocatalysts are also receiving growing attention. So far, most studies involving organic polymers report hydrogen production with sacrificial electron donors, which is unsuitable for large-scale hydrogen energy production. Here we show that a linear conjugated polymer photocatalyst can be used for overall water splitting to produce stoichiometric amounts of H2 and O2. We studied a range of different metal co-catalysts in conjunction with the linear polymer photocatalyst, the homopolymer of dibenzo[b,d]thiophene sulfone (P10). Photocatalytic activity was observed for palladium/iridium oxide-loaded P10, while other co-catalysts resulted in materials that showed no activity for overall water splitting. The reaction conditions were further optimized and the overall water splitting using the IrO2-loaded P10 was found to proceed steadily for an extended period (>60 hours) after the system stabilized. These results demonstrate that conjugated polymers can act as single component photocatalytic systems for overall water splitting when loaded with suitable co-catalysts, albeit currently with low activities. Significantly, though, organic polymers can be designed to absorb a large fraction of the visible spectrum, which can be challenging with inorganic catalysts. Transient spectroscopy shows that the IrO2 co-catalyst plays an important role in the generation of the charge separated state required for water splitting, with evidence for fast hole transfer to the co-catalyst. This solid-state approach should be transferable to other polymer photocatalysts, allowing this field to move away from sacrificial hydrogen production towards overall water splitting.

Nb3O7OH Nanoarrays for Photocatalytic Water Splitting: Defects, Dopants, and Stability of co-Catalysts

2018 ◽  
Author(s):  
Christina Scheu ◽  
Sophia Betzler ◽  
Thomas Gänsler ◽  
Katharina Hengge ◽  
Anna Frank ◽  
...  
Keyword(s):  
Water Splitting ◽  
Photocatalytic Water Splitting ◽  
Co Catalysts

Assembly of thiacalix[4]arene-supported high-nuclearity Cd24 cluster with enhanced photocatalytic activity

Nanoscale ◽  
2018 ◽  
Vol 10 (30) ◽  
pp. 14448-14454 ◽  
Author(s):  
Cheng Shi ◽  
Min Zhang ◽  
Xinxin Hang ◽  
Yanfeng Bi ◽  
Liangliang Huang ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Water Splitting ◽  
Co Catalyst ◽  
Photocatalytic Water Splitting

A high-nuclearity Cd24 cluster built from Cd4-thiacalix[4]arene SBUs and in situ generated peroxyphosphate PO53− exhibited significant photocatalytic water splitting activity in absence of a co-catalyst.

scholarly journals Mechanism for spontaneous oxygen and hydrogen evolution reactions on CoO nanoparticles

2019 ◽  
Vol 7 (12) ◽  
pp. 6708-6719 ◽  
Author(s):  
Kyoung-Won Park ◽  
Alexie M. Kolpak
Keyword(s):  
Hydrogen Evolution ◽  
Water Splitting ◽  
High Efficiency ◽  
Applied Bias ◽  
Co Catalyst ◽  
Photocatalytic Water Splitting ◽  
Overall Water Splitting ◽  
Nanoparticle Suspensions ◽  
Hydrogen Evolution Reactions ◽  
Coo Nanoparticles

Overall photocatalytic water splitting with a high efficiency has recently been observed for CoO nanoparticle suspensions in the absence of an applied bias or co-catalyst. This study clarifies the mechanism of spontaneous overall water splitting with the prominent efficiency observed on the CoO nanoparticle.

scholarly journals Design of a Concentrator With a Rectangular Flat Focus and Operation With a Suspension Reactor for Experiments in the Field of Photocatalytic Water Splitting

2014 ◽  
Author(s):  
Michael Wullenkord ◽  
Christian Jung ◽  
Christian Sattler
Keyword(s):  
Water Splitting ◽  
High Performance ◽  
Performance Test ◽  
Test Facility ◽  
Angle Of Incidence ◽  
Solar Concentrator ◽  
Tracking Accuracy ◽  
Photocatalytic Water Splitting ◽  
Maximum Angle ◽  
Production Of Hydrogen

Photocatalytic water splitting is a potential route for future carbon-free production of hydrogen. However catalysts still need to be enhanced in order to reach acceptable solar-to-fuel efficiency. In the context of the project HyCats funded by the Federal Ministry of Education and Research of Germany a high performance test facility for the evaluation of the activity of photocatalysts under practical conditions was established. It mainly consists of a solar concentrator and a planar receiver reactor. A modified linear Fresnel concentrator configuration was chosen based on ray tracing simulation results and improved concerning the number of different facets and the tolerance of tracking errors. It meets the major demand of a homogeneous irradiance distribution on the surface of the reactor. The SoCRatus (Solar Concentrator with a Rectangular Flat Focus) is a 2-axis solar concentrator with a geometrical concentration ratio of 20.2 and an aperture area of 8.8 m2. The tracking accuracy is better than 0.1° respecting both the solar azimuth and altitude angle. Its 22 highly UV/Vis-reflective flat aluminum mirror facets reflect the sunlight resulting in a rectangular focus with a nominal width of 100 mm and a nominal length of 2500 mm. The reactor is placed in the focal plane at a distance of 2500 mm from the mounting plane of the facets and allows concentrated solar radiation to penetrate suspensions of water, electrolytes and photocatalyst particles flowing through it. Corresponding to a maximum angle of incidence of 36.6° the Quartz window reflects not more than 5% of the incoming radiation and assures only marginal absorption, particularly in the UV-part of the sun’s spectrum. The material of the receiver body is PTFE (polytetrafluoroethylene) providing reflection coefficients above 90% concerning wavelengths of UV-A and UV-B. The design of the reactor features two parallel reaction chambers, offering the possibility to test two separate suspensions at the same irradiation conditions. A pump transports the tempered suspension to the reactor. The geometry of the reactor inlet and outlet minimizes critical regions with inadequate flow caused by vortices. Any evolved gases are separated from the suspension in a tank together with nitrogen introduced in the piping upstream and are analyzed by micro chromatographs. Numerous devices are installed in order to control and monitor the reaction conditions. First experiments have been carried out using methanol as a sacrificial reagent.

scholarly journals p-n Based Photoelectrochemical Device for Water Splitting Application Alpha-Hematite (α-Fe2O3)-Titanium Dioxide (tio2) as N-Electrode & Polyhexylthiophene (rrphth) - Nanodiamond (ND) as P-Electrode

MRS Advances ◽  
2018 ◽  
Vol 3 (13) ◽  
pp. 697-706
Author(s):  
Hussein Alrobei ◽  
Hye Young Lee ◽  
Ashok Kumar ◽  
Manoj K. Ram
Keyword(s):  
Titanium Dioxide ◽  
Water Splitting ◽  
Uv Light ◽  
Visible Region ◽  
Visible Spectrum ◽  
Clean Energy ◽  
Weight Percentage ◽  
Production Of Hydrogen ◽  
Electron Hole Pair ◽  
Physical And Chemical

ABSTRACTRecently, photoelectrochemical (PEC) water splitting using semiconductor photoanode has received great attention due production of hydrogen through clean energy. The alpha hematite (α Fe2O3) is one of the candidate amongst photoanodic materials, which is chemically stable, abundant in nature with a band gap of 2.0-2. 2eV allowing to be harvesting in the visible light. However, it has also drawn back due to high recombination rate of electron–hole pair revealing the low concentration of charges and lower device performance. In common with α-Fe2O3, the titanium dioxide (TiO2) has been known as one of the most explored photoanode electrode material due to its physical and chemical stability in aqueous and non-toxicity. However, TiO2 has large bandgap (3.0-3.2 eV) that results in absorbing UV light and very small part of visible region. Incorporation of TiO2 in α-Fe2O3 could achieve better efficiencies as photoanode materials by enhancing the electric conductivity, limited hole diffusion length, and both materials can absorb light in both UV and visible spectrum range. However, the photoanodic properties of α-Fe2O3 with different concentrations of TiO2 are mostly unknown. Under this work, α-Fe2O3-TiO2 nanomaterial was synthesized using a hydrothermal method. The α-Fe2O3-TiO2 nanomaterials containing different weight percentage (2.5, 5, 16, 25, and 50) of TiO2 to α-Fe2O3 were characterized using SEM, XRD, UV-Vis, FTIR and Raman techniques, respectively. The electrochemical properties of α-Fe2O3-TiO2 nanomaterials were investigated by cyclic voltammetry and chronoamperometry techniques, respectively.

Phosphorus-doped porous carbon nitride for efficient sole production of hydrogen peroxide via photocatalytic water splitting with a two-channel pathway

2020 ◽  
Vol 8 (7) ◽  
pp. 3701-3707 ◽  
Author(s):  
Jingjing Cao ◽  
Hui Wang ◽  
Yajie Zhao ◽  
Yan Liu ◽  
Qingyao Wu ◽  
...  
Keyword(s):  
Water Splitting ◽  
Porous Carbon ◽  
Water Oxidation ◽  
Carbon Nitride ◽  
Normal Pressure ◽  
Photocatalytic Water Splitting ◽  
Oxygen Reduction Reactions ◽  
Production Of Hydrogen ◽  
Sacrificial Agent ◽  
Phosphorus Doped

The P-doped porous carbon nitride achieves photocatalytic water splitting via a two-channel pathway (water oxidation/oxygen reduction reactions) with high H2O2 yield of 1968 μmol g−1 h−1 under room temperature and normal pressure without sacrificial agent and cocatalyst.

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