Photocathode For Hydrogen Generation Research Articles

Promising porous spherical PbI2/poly-2-aminobenzenethiol nanocomposite as a photocathode for hydrogen generation from Red Sea water

A highly efficient porous spherical nanocomposite photocathode, known as PbI2/poly-2-amino benzene thiol (PbI2/P2ABT), is created through a two-step reaction process involving the oxidation of 2-amino benzene thiol with iodine, followed by a double displacement reaction. The resulting nanocomposite displays outstanding morphology, comprising spherical particles with a diameter of 500 nm and featuring nanoscale porosity with pore sizes around 5 nm. Notably, the hydrogen production estimate reaches 9.6 μmole/h·10 cm2, a promising outcome attributed to the environmentally friendly and cost-effective use of natural Red Sea water. The quantification of hydrogen gas is accomplished by assessing the photogenerated carriers using the current density relationship. The calculated Jph value experiences a substantial increase to −0.122 mA.cm−2 compared to a minimal 0.07 mA.cm−2 in the absence of light. Furthermore, the optical assessment reveals exceptional Jph values under 340 nm, reaching 0.121 mA.cm−2, which extends to the visible spectrum with a value of 0.112 mA.cm−2. The remarkable features of this nanocomposite include its cost-effectiveness, ease of fabrication, and scalability for mass production. These qualities collectively enable the conversion of Red Sea water into hydrogen gas, offering a practical and efficient solution aligned with eco-friendly and economically viable practices. This nanocomposite shows significant potential for advancing clean energy technologies and contributing to sustainable hydrogen production from natural water sources.

Superior photoelectrodes of nanostructured Mo-doped CuO thin film for green hydrogen generation from photoelectrochemical water-splitting

Green hydrogen has an audible echo in the clean energy field. In this piece of work, pure and Mo-doped CuO thin films were deposited at different substrate temperatures on the Indium Tin Oxide (ITO) by the DC/RF sputtering technique. The prepared samples were utilized to generate hydrogen gas within the photoelectrochemical water-splitting mechanism. Crystallographic planes (−111), and (200) were the preferred orientations for pure and Mo-doped CuO thin films. Moreover, the average crystallite size was doubled by Mo doping reaching 25.8 nm. FE-SEM microscopic image exhibits that the pure and Mo–CuO thin films have a regular distribution with a small size. The optical band gap has rosed by doping from 1.8 eV to 2.05 eV. Then, it increased to 2.3 eV and 2.4 eV at temperatures of 100 °C and 200 °C respectively. Pure and Mo–CuO thin films were applied as photocathodes for hydrogen generation with water water-splitting technique. The photoelectrochemical application revealed a photocurrent density of ∼2.25 mA/cm2 for Mo-doped CuO photoelectrode at room temperature. This optimum photoelectrode was studied for stability and electrochemical impedance. In addition, the incident photon to current efficiency (IPCE%) was 4.47 % at 500 nm. The applied bias photon to current conversion efficiency (ABPE%) was 4.25 % at −0.38V. As a result of the above, pure and Mo-doped CuO photoelectrodes are low-cost thin films and have a high-efficiency performance for green hydrogen generation industrially.

Photoelectrochemical Hydrogen Production by a Cobalt Tetrapyridyl Catalyst Using Push–Pull Dye‐Sensitized NiO Photocathodes

Herein, the synthesis and optoelectronic properties of a novel push–pull organic dye, pRK1, specifically designed for use in dye‐sensitized photocathodes for hydrogen generation, are reported. The chemical structure of this dye, which incorporates a benzothiadiazole moiety, is inspired by RK1, a dye previously reported as a photosensitizer in n‐type dye‐sensitized solar cells (DSSCs) with power conversion efficiencies above 10% and high stability. The photoelectrochemical activity for hydrogen evolution of pRK1 after grafting onto NiO photocathodes in combination with a cobalt tetrapyridyl catalyst [Co(bapbpy)(OH2)2](BF4)2 in aqueous solution is evaluated and compared with two reference dyes from the literature, RuP2‐bpy and P1. It is shown that among the three photocathodes studied in this work, NiO|pRK1 is the most efficient, producing up to 1.9 μmol cm−2 of hydrogen with a faradaic efficiency of 66%, under visible light irradiation in aqueous electrolyte at pH 4.5. pRK1 shows a turnover number (TONdye) of up to 145 during the 6 h chronoamperometric test, almost twice that of P1. This study demonstrates that the chemical structure of high performance dyes commonly used in DSSCs can be successfully modified to meet the requirements for light‐driven water splitting in dye‐sensitized photoelectrochemical cells.

Photocathode for hydrogen generation using 3C-SiC epilayer grown on vicinal off-angle 4H-SiC substrate

We employed a 3C-SiC epilayer grown on a vicinal off-angle 4H-SiC substrate as a photocathode. The presence of 3C-SiC on the surface of this epilayer was confirmed by optical microscopy and Raman spectroscopy. Spectral responses of the photocathode show high quantum efficiencies in a wide wavelength range. By illuminating the photocathode with full-spectrum solar light of 1.1 W/cm2, the photocurrent was determined to be −13.5 mA/cm2 with a Ni counterelectrode. The generated hydrogen volumes were much larger than those reported previously for SiC photocathodes.

Efficient and Stable MoS2 /CdSe/NiO Photocathode for Photoelectrochemical Hydrogen Generation from Water.

A novel CdSe/NiO heteroarchitecture was designed, prepared, and used as a photocathode for hydrogen generation from water. The composite films were structurally, optically, and photoelectrochemically characterized. The deposition of CdSe on the NiO film enhanced light harvesting in the visible-light region and photoelectrochemical properties. Moreover, the CdSe/NiO photoelectrode showed superior stability both in nitrogen-saturated and air-saturated neutral environments. The CdSe/NiO photoelectrode after MoS2 modification retained the stability of the CdSe/NiO electrode and exhibited higher photocatalytic and photoelectrochemical performances than the unmodified CdSe/NiO electrode. In pH 6 buffer solution, an average hydrogen-evolution rate of 0.52 μmol h(-1) cm(-2) at -0.131 V (versus reversible hydrogen electrode, RHE) was achieved on a MoS2 /CdSe/NiO photocathode, with almost 100 % faradaic efficiency.

Silicon decorated with amorphous cobalt molybdenum sulfide catalyst as an efficient photocathode for solar hydrogen generation.

The construction of viable photoelectrochemical (PEC) devices for solar-driven water splitting can be achieved by first identifying an efficient independent photoanode for water oxidation and a photocathode for hydrogen generation. These two photoelectrodes then must be assembled with a proton exchange membrane within a complete coupled system. Here we report the preparation of a Si/a-CoMoSx hybrid photocathode which shows impressive performance (onset potential of 0.25 V vs RHE and photocurrent jsc of 17.5 mA cm(-2) at 0 V vs RHE) in pH 4.25 phosphate solution and under simulated AM 1.5 solar illumination. This performance is among the best reported for Si photocathodes decorated with noble-metal-free catalysts. The electrode preparation is scalable because it relies on a photoassisted electrodeposition process employing an available p-type Si electrode and [Co(MoS4)2](2-) precursor. Investigation of the mechanism of the Si/a-CoMoSx electrode revealed that under conditions of H2 photogeneration this bimetallic sulfide catalyst is highly efficient in extracting electrons from illuminated Si and subsequently in reducing protons into H2. The Si/a-CoMoSx photocathode is functional over a wide range of pH values, thus making it a promising candidate for the construction of a complete solar-driven water splitting PEC device.

Solar Hydrogen Generation with Wide‐Band‐Gap Semiconductors: GaP(100) Photoelectrodes and Surface Modification

GaP, with its large band gap of 2.26 eV (indirect) and 2.78 eV (direct), is a very promising candidate for direct photoelectrochemical water splitting. Herein, p-GaP(100) is investigated as a photocathode for hydrogen generation. The samples are characterized after each preparation step regarding how their photoelectrochemical behavior is influenced by surface composition and structure using a combination of electrochemical and surface-science preparation and characterization techniques. The formation of an Ohmic back contact employing an annealed gold layer and the removal of the native oxides using various etchants are studied. It turns out that the latter has a pronounced effect on the surface composition and structure and therefore also on the electronic properties of the interface. The formation of a thin Ga(2)O(3) buffer layer on the p-GaP(100) surface does not lead to a clear improvement in the photoelectrochemical efficiency, neither do Pt nanocatalyst particles deposited on top of the buffer layer. This behavior can be understood by the electronic structure of these layers, which is not well suited for an efficient charge transfer from the absorber to the electrolyte. First experiments show that the efficiency can be considerably improved by employing a thin GaN layer as a buffer layer on top of the p-GaP(100) surface.

Visible light driven hydrogen production from a photo-active cathode based on a molecular catalyst and organic dye-sensitized p-type nanostructured NiO

A molecular device with a photocathode for hydrogen generation has been successfully demonstrated, based on an earth abundant and inexpensive p-type semiconductor NiO, an organic dye P1 and a cobalt catalyst Co1.