Photoelectrochemical system based on semiconductor nanomaterials and graphene structures for solar hydrogen production (original) (raw)
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Photoelectrochemical properties of the composites based on TiO2 nanotubes, CdSe and graphene oxide
Research on Chemical Intermediates, 2019
The photoelectrochemical properties of electrodes based on a nanocomposite consisting of TiO 2 nanotubes and CdSe films modified with graphene oxide have been studied. It is shown that in such a nanocomposite, a good adhesion of the CdSe layer to the substrate is provided. In this nanocomposite, the cathodic dark leakage currents are lower, and the efficiency of photoelectrodes is higher. From studies of Raman spectra, in which 2LO and 3LO phonon lines were observed, the quality of the modified polycrystalline films of CdSe was concluded. The amount of graphene oxide in NT-TiO 2 /CdSe/GO composite was determined to be 1.16 mass%, which allows one to obtain optimal photosensitivity of electrodes. It was established that the introduction of graphene oxide into semiconductor electrodes leads to an increase in their photosensitivity which is associated with a decrease of the surface recombination rate. The efficiency of the investigated nanocomposites in the photoelectrochemical cell for hydrogen production was studied together with composites based on graphene materials.
The photoelectrochemical cell with hydrogen accumulation at the conditions of natural insolation
French-Ukrainian journal of chemistry, 2018
The film photoanodes based on CdSe and NT-TiO2/CdSe have been formed by the electrochemical and painting methods. It is shown that the introduction of graphene oxide into the structure of the semiconductor CdSe film promotes absorption of light and leads to improvement in their characteristics by 25-30 %. The compatibility of the cathode based on composite of hydrogensorbing intermetallic alloys LaNi4.5Mn0.5 + LaNi3.5Al0.7Mn0.8 with current-conductive additives in pair with the CdSe photoanode is shown. It was found that 95-98 % of the total current generated under the influence of sunlight at the anodes was used on the formation and accumulation of hydrogen by cathodes.
Physical Chemistry Chemical Physics, 2014
We report on the fabrication of CdSe quantum dot (QD) sensitized electrodes by direct adsorption of colloidal QDs on mesoporous TiO 2 followed by 3-mercaptopropionic acid (MPA) ligand exchange. High efficiency photoelectrochemical hydrogen generation is demonstrated by means of these electrodes. The deposition of ZnS on TiO 2 /CdSe further improves the external quantum efficiency from 63% to 85% at 440 nm under À0.5 V vs. SCE. Using the same photoelectrodes, solar cells with the internal quantum efficiency approaching 100% are fabricated. The ZnS deposition increases the photocurrent and chemical stability of the electrodes. Investigation of the carrier dynamics of the solar cells shows that ZnS enhances the exciton separation rate in CdSe nanocrystals, which we ascribe to the formation of a type II heterojunction between ZnS and CdSe QDs. This finding is confirmed by the dynamics of the CdSe photoluminescence, which in the presence of ZnS becomes noticeably faster. † Electronic supplementary information (ESI) available: Electrochemical reaction in photoanodes and cathodes, the effects of MPA ligand exchange for QDSSCs, absorbance, transmittance and reflectance spectra, photoluminescence of samples with different sequences of CdSe and ZnS on TiO 2 , electrochemical impedance spectroscopy (EIS) measurements, equivalent circuit fitting results of EIS and other parameters of cells, and TRPL fitting results. See
Advanced Energy Materials, 2018
robust, and highly efficient semiconductors; the latter should have good conductivity, be able to transfer charges rapidly at the semiconductor/liquid electrolyte interface, display long-term stability, possess good light-harvesting properties, and have a suitable energy band position for the desired reaction. [6,7] Despite significant progress in this field, [3,10-17] semiconductors that fulfill all these requirements rarely exist today, and the production of such semiconductors is still much sought after. Over the past few years, polymeric graphitic carbon nitride (CN) has attracted widespread attention due to its outstanding electronic properties, which have been exploited in various applications, including photo-and electrocatalysis, [18-24] heterogeneous catalysis, [25-28] CO 2 reduction, [29-31] water splitting, [32-40] light-emitting diodes, [41] photovoltaics, [42-44] and sensing. [45-47] Its unique and tunable optical, chemical, and catalytic properties, alongside its low price and remarkably high stability to oxidation, make it a very attractive material for PEC applications. [11,48,49] However, despite the great progress in utilizing CN materials in PECs, several factors still hinder the cell activity, such as poor electron-hole separation efficiency, short electron diffusion length owing to the poor electronic conductivity of CN materials, deficient hole transfer from the CN surface to solution, and low absorption coefficient. [25] We envision that the improvement of the electron diffusion length would result in significant enhancement of the electron and hole lifetimes and would increase their probability to reach the conductive substrate and the electrolyte, respectively, prior to their recombination. Moreover, a longer diffusion length allows the construction of a thicker absorber layer, thus increasing the surface density of accessible photoactive sites. One way to improve both charge separation and electron diffusion length is by compositing CN with conductive carbon materials, such as graphene and carbon nanotubes. [11,18,19] Upon illumination, excited electrons can be promptly injected into the conductive graphene, while the holes remain in the CN matrix. Consequently, the lifetime of the excitons is prolonged, enhancing their probability for further reaction. To date, various CN/graphene composites have been introduced, mainly as powders, and have demonstrated good photoactivity. [11,18,19] However, the poor dispersibility of CN/graphene composites in most solvents Polymeric carbon nitride (CN) has emerged as a promising semiconductor for energy-related applications. However, its utilization in photo-electrochemical cells is still very limited owing to poor electron-hole separation efficiency, short electron diffusion length, and low absorption coefficient. Here the synthesis of a highly porous carbon nitride/reduced graphene oxide (CN-rGO) film with good photo-electrochemical properties is reported. The CN-rGO film exhibits long electron diffusion length and high electrochemical active surface area, good charge separation, and enhanced light-harvesting properties. The film displays a 20-fold enhancement of photocurrent density over pristine CN, reaching up to 75 µA cm −2 at 1.23 V versus reversible hydrogen electrode (RHE) in an alkaline solution, as well as stability over a wide pH range. Photocurrent measurements with a hole scavenger reveal a photocurrent density of 660 µA cm −2 at 1.23 V versus RHE and a quantum efficiency of 60% at 400 nm, resulting in the production of 0.8 mol h −1 g −1 of hydrogen. The substantial photo-electrochemical activity enhancement and hydrogen production together with the low price, high electrochemical surface area, long electron diffusion length, stability under harsh condition, and tunable photophysical properties of CN materials open many possibilities for their utilization in (photo)electrochemical and electronic devices.
Journal of Physics Conference Series 09/2009; 182(1):012080. DOI:DOI:10.1088/1742-6596/182/1/012080 , 2009
Abstract. It was built a versatile photoelectrochemical cell devoted to the comparative study of the photosensitive materials used as photoelectrodes in solar-hydrogen production. The experimental arrangement make possible a relative evaluation of the electrodes properties by the measurement of the electric parameters, giving directly I = f (U) for the cell electric circuit with and without an external electrical bias. It also gives a direct measurement of the volume of the evolved gases, and an on-line analyze of the gases by the coupled gas chromatograph, or of-line, by a mass spectrometer.
Nanostructures based photoelectrochemical cells for energy conversion
In this paper, we present a comparative study of photoelectrochemical cells based on the films nanoparticles (NPs) and nanowires (NWs) of cadmium sulphide (CdS) thin films grown by chemical bath deposition (CBD) and wet chemical etching. The CdS samples are characterized by XRD, SEM and UV-vis absorption spectroscopy. The cell configuration n-CdS/1M (NaOH-Na2S-S)/C(graphite) is used for studying the I-V characteristics under illumination, photovoltaic output characteristics and transient photoresponse. Performance of the PEC cell is found to be improved by converting NPs of CdS into NWs.
Solar energy conversion using CdSe photoelectrochemical cells with low cost substrates
Solar Cells, 1980
Photoelectrochemical cells using electrocodeposited CdSe films on low cost substrates (stainless steel and graphite) were studied. The usefulness of graphite as a counterelectrode in place of platinum was demonstrated. Results are reported for three cell configurations: stainless steel lCdSell electrolyte II Pt; stainless steel I CdSe [I electrolyte li C; C [CdSe [[ electrolyte II Pt.
In this paper it was made a comparative study of the doped TiO2 thin films used as photoelectrodes by using a versatile photoelectrochemical cell. The experimental arrangement makes possible the relative evaluation of the electrodes properties by measurement of the electric parameters, giving directly I = f(U) for the cell electric circuit by using an "internal" chemical bias. It is also possible to measure the volume of the evolved gas, and to analyze it by a gas-chromatograph and by a mass spectrometer.
Semiconductor based nanomaterials for harvesting green hydrogen energy under solar light irradiation
International Journal of Environmental Analytical Chemistry, 2020
In this review, the evolution of hydrogen in a combined cell system of photoelectrocatalytic and microbial fuel is discussed. Hydrogen is used as chemical fuel and being produced through photoelectrocatalytic method. The semiconductor material was put into the water and irradiated with solar light. After that, the hydrogen is produced by different steps and accumulated. Production of hydrogen also takes place in a microbial fuel cell system. These are electrochemical devices that are initially used to treat the wastewater. But now, this cell has entered into a very interesting field of research which is Bioelectrochemical system (BES). BES produces hydrogen by using biomass as a catalyst and small consumption voltage rather than simple electrolysis of water. The first section explains how hydrogen can be produced individually by these two methods. Then, a comprehensive review is presented on the evolution of hydrogen by combining microbial fuel and photoelectrocatalytic cell system. The continuous production of hydrogen by using (PEC-MFC) hybrid device, sunlight and splitting of water and electro-hydro genesis of microbial cell in fusion device (PEC-MFC) are also reported. This method gives continuous production of hydrogen using wastewater under solar light and also gives the treatment of wastewater. It is a clean energy source and also fulfils today's demand for energy. At last, a review on the production of hydrogen by the microbial photoelectrochemical system is constructed by photocathode of semiconductor material and an anode of microbial. Production of hydrogen was continuously achieved without external voltage under ultraviolet irradiation.
Journal of Nanoparticle Research, 2013
In this work, we developed a new type of nanostructured photoanodes for photoelectrochemical water splitting. They are based on CdS-TiO 2 nanocomposite films, supported on conductive Ti sheets, prepared by an easy-to-achieve three-step method. It involves the production of TiO 2 nanofibers (NFs) using a controlled corrosion route of polished Ti sheets, the preparation of size-controlled CdS quantum dots (QDs) by the polyol process and the direct impregnation of TiO 2 /Ti sheets by QDs in suspension. The photoelectrochemical (PEC) properties of the resulting nanostructures were measured, using a homemade electrochemical cell illuminated with a standard Xenon lamp, and compared to those of bare TiO 2 NFs. A net enhancement of the photocurrent was observed after CdS impregnation, suggesting a low carrier recombination rate and a higher efficiency of the PEC device for solar water splitting, as the induced photocurrent is related to the electrons needed to reduce H + ions into H 2 at the cathode electrode (Pt wire). Keywords TiO 2 nanofibers CdS quantum dots CdS-TiO 2 /Ti nanocomposites Photoelectrochemical properties X-ray photoelectron spectroscopy Electron microscopy Energy conversion