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A review on photoelectrochemical hydrogen production systems: Challenges and future directions
摘要： Water photolysis is a fundamental concept in which solar-driven water splitting is utilized to generate renewable hydrogen fuel using semiconductor-based electrochemical systems. The engineering design principles for each system configuration, including single, dual/tandem photoelectrodes, tandem photoelectrochemical-photovoltaic, and multi-junction designs are reviewed. Modeling and numerical simulation of photoelectrochemical processes based on up-to-date multi-scale analysis are presented and discussed. In addition, the achievements made in semiconductor photoelectrode materials and the rational engineering methods needed to improve the solar to hydrogen efficiency are demonstrated. Furthermore, some key accomplishments in different aspects, such as electron-hole recombination, stability, photocorrosion, energy band gap, and photocurrent density are discussed. Moreover, key points on the challenges, opportunities and future directions towards commercialization of viable photoelectrochemical reactors are discussed.
关键词： Semiconductor materials,Photoelectrochemical process,Hydrogen production,Solar energy
更新于2025-09-23 15:23:52
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A new insight for photocatalytic hydrogen production by a Cu/Ni based cyanide bridged polymer as a co-catalyst on titania support in glycerol water mixture
摘要： A two dimensional Cu/Ni based coordination polymer (CP-1) $0.7(C2H6O2)$1.6(H2O) (4,4?-dipy ? 1,3-di(4-pyridyl)propane) has been demonstrated as a potential co-catalyst on TiO2 support for hydrogen evolution under UV light. CP-1/TiO2 composite exhibits considerable hydrogen production in comparison with the pristine CP-1 and TiO2 (P25), highlighting that the photocatalytic performance is significantly related with the good separation of photo generated e-/h+ pairs. Different wt. % (2.5, 5 and 7.5%) of CP-1 in CP-1/TiO2 composites were tested for photocatalytic hydrogen production in 5 vol % glycerol/water mixture. The 5 wt % CP-1/TiO2 composite displayed the greatest hydrogen production of 9.2 mmol h-1 g-1. The concealed mechanism is divulged on the behalf of results obtained by cyclic voltammetry, photoluminescence and diffused reflectance/UV-visible studies which demonstrate that upon irradiation of UV light, electrons transfer from TiO2 conduction band to CP-1. CP-1 not only grabs the conduction band electrons of titania but also performes as a co-catalyst to reduce the protons into hydrogen. These results are anticipated to direct the forthcoming advancement in creating proficient, cheap semiconductor photocatalysts for solar hydrogen production.
关键词： Hydrogen,Coordination polymer,Co-catalyst,Photocatalyst,Titanium dioxide
更新于2025-09-23 15:23:52
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Optimizing one-dimensional TiO2 for photocatalytic hydrogen production from a water-ethanol mixture and other electron donors
摘要： This work is focused on synthesizing and employing one-dimensional (1D) titanium dioxide (TiO2) for hydrogen (H2) production. Based on using electron donors (EDs) (ethanol, methanol, formic acid and 1,2,3 propanetriol), the increased H2 production, when compared to P25 TiO2 nanoparticles, was due to the large specific surface area (SSA) and enhanced electron mobility of 1D TiO2. The impact of the 1D TiO2 synthesis reaction conditions (temperature, NaOH concentration and the TiO2 precursor concentration) on the photocatalytic H2 production rate was evaluated using a 3-factor 3-level Box Behnken design (BBD). The BBD model demonstrated that the temperature and the NaOH concentration significantly affected the 1D TiO2 phase structure, crystal size, SSA, bandgap and the photocatalytic H2 production rate. The phase structure and crystal size of 1D TiO2 were key factors affecting the H2 production rate. 1D TiO2 containing an anatase phase with a mean crystal size of 20.1±0.2 nm was synthesized at 126oC, 15 M NaOH and 49 g·L-1 TiO2. The maximum H2 production rate of 475±12 μmol·h-1 (quantum efficiency (ε) = 20.2±0.5%) for the 1D TiO2 sample was significantly enhanced when compared to commercial TiO2 P25. The H2 production rate for the optimized 1D TiO2 was significantly enhanced by decorating the structure with Pt and Au. Hydrothermal synthesized of 1D TiO2 provided an efficient and low cost method for producing H2 from ethanol, methanol, formic acid and 1,2,3 propanetriol.
关键词： hydrogen production,hydrothermal,1D titanium dioxide,TiO2-B,anatase,photocatalyst,quantum yield
更新于2025-09-23 15:23:52
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Synthesis and fluorescence studies of selected N-aryl-2-aminoquinolines: Effect of hydrogen bonding, substituents and ESIPT on their fluorescence quantum yields
摘要： N-aryl-2-aminoquinolines have been widely synthesised and used in biological applications. However, their luminescence properties have not been studied in detail. Herein a series of N-aryl-2-aminoquinolines was synthesised from substitution reaction between 2-chloroquinoline and anilines with different substituent groups gave sufficient yield from 72–90%. The fluorescence behaviour was investigated in toluene, ethyl acetate and ethanol. The result shows that fluorescence quantum yield of N-aryl-2-aminoquinolines was the highest in toluene, followed by in ethyl acetate and the lowest in ethanol. Quenched emission observed in ethanol is caused by site-specific fluorophore-solvent hydrogen bonding interactions, inducing deactivation of the quinolinyl ring system. The bell-shaped Hammett plot of various substituted compounds suggested that both strong electron donating and electron withdrawing groups caused significant quenching in the fluorescence quantum yields. Therefore, most types of substituent groups on the phenyl moiety, hydrogen bonding between the fluorophore and solvent, and excited-state intramolecular proton transfer (ESIPT) were found as crucial contributors to fluorescence quenching of N-aryl-2-aminoquinolines.
关键词： Substituent effects,ESIPT,Hydrogen bonding,N-aryl-2-aminoquinolines,Fluorescence quenching
更新于2025-09-23 15:23:52
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Snowflake-like Cu2S/Zn0.5Cd0.5S p–n heterojunction photocatalyst for enhanced visible light photocatalytic H2 evolution activity
摘要： Building a p–n heterojunction can accelerate the separation and transfer of photoinduced charges, which is considered to be a promising approach to constructing photocatalysts with excellent H2 evolution activities. Herein, novel snowflake-like Cu2S/Zn0.5Cd0.5S heterojunction photocatalysts were successfully synthesized. Compared to the pure Cu2S and Zn0.5Cd0.5S, the as-synthesized Cu2S/Zn0.5Cd0.5S showed remarkably improved H2 evolution rate. Cu2S/Zn0.5Cd0.5S with a Cu2S content of 3 wt% showed the optimized H2 evolution rate of 4923.5 μmol g?1 h?1 in Na2S–Na2SO3 solutions, and the corresponding apparent quantum efficiency is 30.2% at 420 nm. The experimental results indicate that the enhanced H2 evolution rates can be attributed to the fabrication of the p–n heterojunction between Cu2S and Zn0.5Cd0.5S, effectively boosting photogenerated charge carriers separation and transfer. Moreover, a plausible mechanism was proposed.
关键词： Photocatalytic,Hydrogen production,Snowflake-like,p–n heterojunction
更新于2025-09-23 15:23:52
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Synthesis of a MoS <i> <sub/>x</sub></i> -O-PtO <i> <sub/>x</sub></i> Electrocatalyst with High Hydrogen Evolution Activity Using a Sacrificial Counter-Electrode
摘要： Water splitting is considered to be a very promising alternative to greenly produce hydrogen, and the key to optimizing this process is the development of suitable electrocatalysts. Here, a sacrificial-counter-electrode method to synthesize a MoSx/carbon nanotubes/Pt catalyst (0.55 wt% Pt loading) is developed, which exhibits a low overpotential of 25 mV at a current density of 10 mA cm?2, a low Tafel slope of 27 mV dec?1, and excellent stability under acidic conditions. The theory calculations and experimental results confirm the high hydrogen evolution activity that is likely due to the fact that the S atoms in MoSx can be substituted with O atoms during a potential cycling process when using Pt as a counter-electrode, where the O atoms act as bridges between the catalytic PtOx particles and the MoSx support to generate a MoSx–O–PtOx structure, allowing the Pt atoms to donate more electrons thus facilitating the hydrogen evolution reaction process.
关键词： sacrificial-counter-electrodes,O substitution,MoSx,hydrogen evolution reaction,PtOx
更新于2025-09-23 15:23:52
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Ru(II) and Ir(III) complexes containing ADA and DAD triple hydrogen bonding motifs: Potential tectons for the assembly of functional materials.
摘要： The synthesis and characterisation of series of [Ru(II)(bpy)2L] and [Ir(ppy)2L] complexes containing ligands L with the potential to engage in triple hydrogen bonding interactions is described. L1 and L2 comprise pyridyl triazole chelating units with pendant diaminotriazine units, capable of donor-acceptor-donor (DAD) hydrogen bonding, while L3 and L4 contain ADA hydrogen bonding units proximal to N^N and N^O cleating sites, respectively. X-ray crystallography shows the L1 and L2 containing Ru(II) complexes to assemble via R22(8) hydrogen bonding dimers, while [Ru(II)(bpy)2L4] assembles via extended hydrogen bonding motifs to form one dimensional chains. By contrast, the expected hydrogen bonding patterns are not observed for the Ru(II) and Ir(III) complexes of L3. Spectroscopic studies show that the absorption spectra of the complexes result from combinations of MLCT and LLCT transitions. The L1 and L2 complexes of Ir(III) and Ru(II) complexes are emissive in the solid state and it seems likely that hydrogen bonding to complementary species may facilitate tuning of their 3ILCT emission. Low frequency Raman spectra provide further evidence for ordered interactions in the solid state for the L4 complexes, consistent with the results from X-ray crystallography.
关键词： crystal engineering,ruthenium,Hydrogen bonding,iridium,X-ray crystallography
更新于2025-09-23 15:23:52
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Highly Selective Fluorescent Probe Based on 2-(2′-Dansylamidophenyl)-Thiazole for Sequential Sensing of Copper(II) and Iodide Ions
摘要： A novel highly selective fluorescent probe based on 2-(20-dansylamidophenyl)-4-phenylthiazole (1) is developed for sequential sensing of copper(II) and iodide ions in acetonitrile. The fluorescence mechanism is based on cation-induced inhibition of excited-state intramolecular hydrogen transfer, intramolecular charge transfer, and metal–ligand electron/charge transfer. Subsequent iodide-induced extrusion of copper(II) results in partial revival of fluorescence. Probe 1 and its ensemble with copper (II) show high selectivity for copper(II) and iodide ions, respectively, in acetonitrile solution.
关键词： Excited-state intramolecular hydrogen transfer,I?,Cu2+,Intramolecular charge transfer,Dansyl-thiazole conjugate
更新于2025-09-23 15:23:52
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Electronic Structure and Room Temperature Ferromagnetism in Gd-doped Cerium Oxide Nanoparticles for Hydrogen Generation via Photocatalytic Water Splitting
摘要： Enhanced visible light photocatalytic activity of Gd-doped CeO2 nanoparticles (NPs) is experimentally demonstrated, whereas there are very few reports on this mechanism with rare earth doping. All-pure and Gd-doped CeO2 NPs are synthesized using a coprecipitation method and characterized using X-ray diffraction (XRD), absorption spectroscopy, surface-enhanced Raman Spectroscopy (SERS), X-ray photoelectron spectroscopy (XPS), and superconducting quantum interference device (SQUID). The effect of Gd-doping on properties of CeO2 is discussed along with defects and oxygen vacancies generation. The XRD confirms the incorporation of Gd3+ at the Ce3+/Ce4+ site by keeping the crystal structure same. The average particle size from transmission electron microscopy (TEM) images is in the range of 5–7 nm. The XPS spectra of Ce 3d, O 1s, and Gd 4d exhibits the formation of oxygen vacancies to maintain the charge neutrality when Ce4+ changes to Ce3+. The gradual increase in hydrogen production is observed with increasing Gd concentration. The observed results are in good correlation with the characterization results and a mechanism of water splitting is proposed on the basis of analyses. The absorption spectra reveal optical band gap (2.5–2.7 eV) of samples, showing band gap narrowing leads to desired optical absorbance and photoactivity of NPs.
关键词： water splitting,hydrogen generation,SERS,XPS
更新于2025-09-23 15:23:52
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Facile preparation of KBiO <sub/>3</sub> /g-C <sub/>3</sub> N <sub/>4</sub> composites with microwave irradiation for photocatalytic hydrogen production
摘要： BACKGROUND: KBiO3/g-C3N4 composites were prepared under microwave irradiation to different weight ratio of KBiO3 (5, 10, 20, 30, 40, 50, 60, 70 80, 90 %wt) using a Mars-6 for 30 min at 100 W. The samples were characterization by XRD, FT-IR, SEM, EDS-Mapping, N2 physisorption and DRS. The photocatalytic activity of the samples was evaluated in the hydrogen evolution reaction. RESULTS: The composites were confirmed by XRD, where was observed that the samples up to 60% of KBiO3 it is easy to identify the characteristic peak of g-C3N4. Composites show that KBiO3 was homogeneously dispersed on g-C3N4 according to what was observed by EDS-Mapping. In the photocatalytic tests was observed that when the concentration of g-C3N4 is greater than KBiO3 but up to a certain limit, there is a higher production of hydrogen. CONCLUSIONS: KBiO3/g-C3N4 composites were prepared successfully with microwave irradiation reaching a good synergy between both materials for hydrogen production reaction. This synergy was improved to the use of microwave that facilitates the dispersion and binding of both materials. The sample with best hydrogen production was 40%KBiO3/60%C3N4 with 698 μmol H2/g, which is about 3 times higher than g-C3N4 and 7 times higher than KBiO3.
关键词： KBiO3/g-C3N4,photocatalysis,hydrogen production,microwave method
更新于2025-09-23 15:23:52