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Facile two-step synthesis of porous carbon nitride with enhanced photocatalytic activity using a soft template
摘要： In this study, we successfully synthesized a thin-slice layer of graphitic carbon nitride (g-C3N4) with abundant irregular holes by a facile two-step way using Pluronic P123 as a template (CN-P123-x, where x represents the mass ratio of melamine to Pluronic P123). The characterization data suggest that the introduction and removal of Pluronic P123 altered the chemical material structure of the carbon nitride. The CN-P123-x presented lamellar structure with irregular holes, whereas H-g-C3N4 (g-C3N4 prepared using a mild hydrothermal and calcination method without Pluronic P123 or HCl) has a dense blocky structure. Additionally, the prepared CN-P123-x exhibited an effective Rhodamine B (RhB) degradation rate of 98.7% within 40 min of illumination. The optimal photocatalytic activity of CN-P123-6 for degrading RhB was 13.9 times greater than that of H-g-C3N4 in terms of the kinetic constant. Furthermore, the H2 evolution rate of CN-P123-6 can reach 1074.9 μmol?g?1?h?1, whereas that of H-g-C3N4 is only 3.1 μmol?g?1?h?1. It is worth noting that the adoption of HCl (H-g-C3N4-HCl) and Pluronic P123 (CN-P123-6 without HCl) alone has no insignificant effect on photocatalytic performance. The intensive activities are on account of the irregular pores in the thin slice, which increase the specific surface area of the sample and provide additional active sites for reaction. This work provides an excellent basis for improving the performance of the photocatalytic degradation and hydrogen production of carbon nitride.
关键词： Rhodamine B (RhB),H-g-C3N4,hydrogen production,photocatalytic degradation,CN-P123-x
更新于2025-09-23 15:22:29
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Electronic structure and hydrogen evolution reaction in layered ReS<sub>2</sub> regulated by alkali-metal atom intercalation
摘要： Recently, the atom intercalation method has been developed and applied into two-dimensional (2D) materials to regulate their pristine physical property. However, as an important application in hydrogen evolution reaction (HER), the influence of alkali-metal-intercalated technology upon 2D material's electronic structure and catalytic activity should be investigated systematically. In this work, layered ReS2 crystals with a charge decoupling are chosen as a model to explore changes in electronic structure and Gibbs free energies induced by alkali-metal intercalated compounds and external strain. The calculated results disclose that the structural transformation induced by intercalated alkali atom and external strain not only leads to decrease in band gap of ReS2 but also make Gibbs free energy of adsorbed hydrogen close to zero. Our calculations provide an insight to improve HER performance by a simple alkali-metal-intercalated technology.
关键词： hydrogen evolution reaction,electronic structure,alkali-metal-intercalated technology
更新于2025-09-23 15:22:29
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High sensitivity fiber optic sensor for hydrogen detection in gas and transformer oil
摘要： This paper reports on the characterisation of a palladium (Pd) based fiber optic hydrogen (H2) sensor for health monitoring of distribution and power transformers in the electrical grid. The sensor consists of a Pd foil, which expands due to H2 absorption, and a fiber Bragg grating (FBG) that measures this expansion. Fifteen sensors were manufactured and characterised in gas and oil environments at various H2 concentrations and temperatures. In gas, the sensors were evaluated at 60°C, 75°C, 90°C, 105°C and 120°C and H2 concentrations from 0.01 to 5%. In oil, the same sensors were evaluated at 90°C and dissolved H2 concentrations from 5 to 2700 ppm. Furthermore, the influence of carbon monoxide (CO), which is often present in transformers and can impact H2 response of the sensor, was investigated. At 90°C in gas, the response to 0.01%, and 5% H2 was on average 28 pm, and 719 pm respectively. At 90°C in oil, the response to 5 ppm, and 2700 ppm dissolved H2 was on average 11 pm, and 763 pm respectively. The average, relative accuracy is better than 20% over the whole measurement range in gas and for measurements above 100 ppm in oil. These specifications make the sensor a promising candidate for online monitoring of H2 in transformers.
关键词： transformer monitoring,Hydrogen,fiber Bragg grating,palladium,gas detection
更新于2025-09-23 15:22:29
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An In-Depth Study on Electrical and Hydrogen Sensing Characteristics of ZnO Thin Film with Radio Frequency Sputtered Gold Schottky Contacts
摘要： Electrical and hydrogen sensing characteristics of radio frequency sputtered Au/ZnO thin film Schottky diodes on n-silicon substrate have been investigated over a wide temperature range. Current-voltage characterizations of the device in the temperature range of 25°C to 200°C confirm its excellent rectifying property with forward to reverse current ratio of 1610 at an external bias of 5 V. Ideality factor in the range of 4.12 to 2.98 is obtained for Au/ZnO Schottky diode in the aforementioned temperature range, at atmospheric conditions. On exposing diode to hydrogen, a reduction in ideality factor is observed which makes thermionic emission more prominent. The proposed device has proven to be hydrogen sensitive, on account of the lateral shift observed in I ? V characteristics at different hydrogen concentrations (50 ppm-1000 ppm). Maximum barrier height variation of 99 meV and sensitivity of 144% have been observed at 1000 ppm hydrogen at 200°C. A Detailed perusal of the steady-state reaction kinetics of the sensor using I ? V characteristics affirmed that the atomistic hydrogen adsorption at Au/ZnO interface is accountable for the barrier height modulation. The studied sensor depicts remarkable performance for high-temperature detection.
关键词： Hydrogen sensing,Zinc oxide (ZnO) thin film,Electrical characteristics,Schottky diode,Metal-semiconductor interface,Palladium catalyst
更新于2025-09-23 15:22:29
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Analysis of power efficient compressor with fuzzy logic MPPT-based PV/FC system
摘要： In this paper, a hybrid photovoltaic (PV)/fuel cell (FC) power generation system is considered, where the hydrogen generated by the electrolysis process is used for subsequent FC operation. A novel induction motor-based compressor is proposed to boost up the pressure of hydrogen, and hence to improve the performance of the FC system. A fuzzy logic-based maximum power point tracking (MPPT) system is designed for the considered PV system. Finally, a coordinated control scheme is applied for controlling the power supplied to the load by integrating both the sources. The complete model is realised in the MATLAB/Simulink environment. Extensive simulation studies are conducted to verify the developed model. The performance of the complete system is found satisfactory under different conditions.
关键词： electrolyzer system,coordinated control,fuzzy logic-based MPPT,hydrogen generation,solar PV system
更新于2025-09-23 15:22:29
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Polymer Dots Compartmentalized in Liposomes as Photocatalyst for In Situ Hydrogen Therapy
摘要： Semiconducting polymer dots (Pdots) have recently attracted considerable attention because of their photocatalytic activity as well as tunable optical band gap. In this contribution, we describe the therapeutic application of Pdots through in situ photocatalytic hydrogen generation. A liposome was employed as a nanoreactor to confine the Pdot photocatalyst, reactants, intermediates, and by-products. Upon photon absorption by the Pdots, the catalytic cycle is initiated and repeated within the aqueous interior, while the H2 product diffuses across the lipid bilayer to counteract reactive oxygen species (ROS) overexpressed in diseased tissues. Ensemble and single-particle F?rster resonance energy transfer microscopy confirmed the proposed nanoreactor model. We demonstrate that a liposomal nanoreactor containing Pdots and a sacrificial electron donor is a potential photocatalytic nanoreactor for in situ hydrogen therapy.
关键词： compartmentalization,hydrogen therapy,photocatalysis,polymer dots,liposomes
更新于2025-09-23 15:22:29
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Photocatalytic Hydrogen Production Under Near-UV Using Pd-Doped Mesoporous TiO2 and Ethanol as Organic Scavenger
摘要： Photocatalysis can be used advantageously for hydrogen production using a light source (near-UV light), a noble metal-doped semiconductor and an organic scavenger (2.0 v/v% ethanol). With this end, palladium was doped on TiO2 photocatalysts at different metal loadings (0.25 to 5.00 wt%). Photocatalysts were synthetized using a sol-gel method enhancing morphological properties with a soft template precursor. Experiments were carried out in the Photo-CREC Water II reactor system developed at CREC-UWO (Chemical Reactor Engineering Centre- The University of Western Ontario) Canada. This novel unit offers hydrogen storage and symmetrical irradiation allowing precise irradiation measurements for macroscopic energy balances. Hydrogen production rates followed in all cases a zero-order reaction, with quantum yields as high as 30.8%.
关键词： Quantum Yield,Photo-CREC Water II reactor,Palladium,Hydrogen production,TiO2
更新于2025-09-23 15:22:29
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Exfoliated Molybdenum Disulfide Encapsulated in a Metal Organic Framework for Enhanced Photocatalytic Hydrogen Evolution
摘要： An exfoliated MoS2 encapsulated into metal-organic frameworks (MOFs) was fabricated as a promising noble-metal-free photocatalyst for hydrogen production under visible light irradiation. The as-synthesized samples were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and Brunauer–Emmett–Teller (BET) surface analysis. It is well known that bulk MoS2 is unsuitable for photocatalysis due to its inadequate reduction and oxidation capabilities. However, exfoliated MoS2 exhibits a direct band gap of 2.8 eV due to quantum confinement, which enables it to possess suitable band positions and retain a good visible-light absorption ability. As a result, it is considered to be an encouraging candidate for photocatalytic applications. Encapsulating exfoliated MoS2 into MOF demonstrates an improved visible light absorption ability compared to pure MOF, and the highest hydrogen production rate that the encapsulated exfoliated MoS2 could reach was 68.4 μmol h-1g-1, which was much higher than that of pure MOF. With a suitable band structure and improved light-harvesting ability, exfoliated MoS2@MOF could be a potential photocatalyst for hydrogen production.
关键词： hydrogen evolution,ZIF-8,exfoliation,MOF,MoS2,photocatalyst
更新于2025-09-23 15:22:29
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Photo-Induced Phase Transition of CdZnS Based Nanocomposite at Room Temperature Under Solar Irradiation
摘要： Photo-induced phase transition (PIPT) of CdZnS based nanocomposites that was performed at the room temperature under the solar light illumination is reported here for the first time. CdZnS particles were decorated on reduced graphene oxide (RGO) with a solvothermal process and consequently RGO-CdZnS-5%Pt nanocomposites (PC) have been synthesized as zinc blende (cubic) phase of CdZnS. Zinc blende structure (cubic) of CdZnS components of PC was turned to wurtzite (hexagonal) crystal structure with PIPT during the photocatalytic hydrogen evolution reaction. The band gap of the photocatalyst decreased from 2.42 to 2.19 eV and the hydrogen evolution rate increased from 37.3 to 184.0 μ mol h?1 due to the PIPT process.
关键词： Photo-induced phase transition,Hydrogen production,Metal chalcogenides,Photocatalyst
更新于2025-09-23 15:22:29
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Enhanced light harvesting and electron-hole separation for efficient photocatalytic hydrogen evolution over Cu7S4-enwrapped Cu2O nanocubes
摘要： P-type Cu2O is an advantageous photocatalyst as the appropriate bandgap structure and low-cost. However, poor photocatalytic and instability of such promising material is still a great challenge. Here the core-shell Cu7S4-coated Cu2O nanocubes (Cu2O/Cu7S4 NCs) were successfully synthesized by solution method coupled with anion exchange, integrated structure of Cu2O/Cu7S4 NCs exhibited apparent improved photocatalytic hydrogen evolution activity compared with Cu2O photocatalyst. Particularly, Cu2O/Cu7S4 NCs had a high hydrogen production rate of 1689.00 μmol·g-1·h-1 under full spectra irradiation with additives of Na2SO3, which was higher than that of Cu2O NCs with a factor of 1.71 times. Excellent synergistic effect of Cu2O and Cu7S4 can be responsible for the improved hydrogen evolution properties, namely, the presence of Cu7S4 with localized surface plasma resonance (LSPR) can promote the photogenerated electrons transfer from the Cu2O surface, prolong the photogenerated holes lifetime, accelerate the separation of photogenerated electrons and holes, and ameliorate the photoelectric properties of semiconductors. The in situ formed multifunctional Cu7S4 layer offers a promising avenue to design photocathodes rationally for photocatalytic water reduction.
关键词： Photocatalyst,Localized surface plasma resonance,Electron-hole separation,Hydrogen evolution reaction,Cu2O/Cu7S4 nanocubes
更新于2025-09-23 15:22:29