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Optimal Control of a Grid Assisted Photovoltaic-Hydrogen Production System
摘要： This paper deals with the optimal control of a H2 production system supplied by a photovoltaic solar energy and assisted by the grid. For that, we propose a simple dynamic model accounting for the main features of the system, where the electrolizer current is used as the control variable, and we obtain the control law that optimizes the grid energy consumption despites the solar energy variability. An important constraint on the obtained solution is the physical limits of the hydrogen storage tank, which results in a nonsmooth and noncontinuous problem. The Pontryagin’s maximum principle is used to solve the boundary value problem and an explicit piecewise continuous control law is found. Simulation results are presented to illustrate the e?ectiveness of the proposed control design.
关键词： optimal control,renewable systems,Pontryagin’s maximum principle,hydrogen production
更新于2025-09-19 17:13:59
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Synergy of NiO quantum dots and temperature on enhanced photocatalytic and thermophoto hydrogen evolution
摘要： Solar-to-hydrogen holds a great sustainable energy solution, in which photocatalysis plays an important role. In this study, a composite photocatalyst with NiO quantum dots (NiO QDs) in graphitic carbon nitride (g-CN) was synthesized and evaluated in photocatalytic (PC) and thermophotocatalytic hydrogen evolution reaction (HER) under visible light. A sample of 9 wt% NiO QDs-g-CN achieved the highest PC-HER rate of 130 μmol·g-1·h-1 at ambient condition, 11 times higher than pristine g-CN. Meanwhile the thermophotocatalytic HER rate reached 260.2 μmol·g-1·h-1 at 55 °C. Photo-illumination led to the formation of C-O bond between g-CN and NiO QDs to bridge photoelectron transport for low HER overpotential barriers and enhanced electrical conductivity. The higher thermophoto-induced HER can be ascribed to the increased electrical conductivity of NiO QDs-g-CN. This work underlines the importance of chemical binding in hetero-structures and quantum confinement effects in QDs-based composites, and it also demonstrates the thermal sensitivity effect in thermophotocatalytic HER process.
关键词： graphitic carbon nitride,thermophotolysis,hydrogen production,Quantum dots,photocatalysis
更新于2025-09-19 17:13:59
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Experimental investigation and optimization of integrated photovoltaic and photoelectrochemical hydrogen generation
摘要： This paper examines the transport phenomena and optimal performance of an integrated concentrated photovoltaic and photoelectrochemical hydrogen reactor. Individual components and the overall system are studied experimentally including the performance of the concentrator, spectrum-splitting mirror, electrolyser, reactor, and photovoltaic module. Integrating the solar concentration with a spectrum-splitting mirror allows simultaneous photovoltaic electricity generation and direct photonic energy conversion to produce hydrogen via electrolytic and photoelectrochemical water splitting. A multi-objective optimization of the integrated system is performed with machine learning and integration of a neural network. This yields a relationship between the system inputs and outputs. The neural network is used to optimize the overall system through a genetic algorithm. Numerical and experimental results are presented and discussed in the paper.
关键词： Photovoltaic,Photoelectrochemical,Efficiency,Hydrogen production,Solar energy
更新于2025-09-19 17:13:59
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Syzygy Plasmonics
摘要： Using photocatalysis to make chemical reactions more efficient
关键词： plasmonics,photocatalysis,chemical reactions,hydrogen production
更新于2025-09-16 10:30:52
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Charge transfer dynamics and catalytic performance of a covalently linked hybrid assembly comprising a functionalized cobalt tetraazamacrocyclic catalyst and CuInS <sub/>2</sub> /ZnS quantum dots for photochemical hydrogen production
摘要： Although the cobalt complex, [Co(CR)X2]+ (CR ? 2,12-dimethyl-3,7,11,17-tetraazabicyclo[11.3.1]heptadeca-1(17),2,11,13,15-pentaene), has been studied as a catalyst for electro- and photochemical H2 generation and CO2 reduction for more than thirty years, only the unfunctionalized one was used as a free catalyst in bulk solutions. Considering that the immobilization of functionalized molecular catalysts (MCs) on the surface of light harvesting materials through a stable covalent linkage was often an effective strategy to boost the activity of semiconductor/MC hybrid photocatalytic systems, we prepared the first anchoring group-functionalized [Co(CR)X2]+ complex (C1, X ? Br), which bears a (20,60-dicarboxypyridin-40-yl) group at position 15 of the macrocyclic ligand. The covalent attachment of C1 to the surface of CuInS2/ZnS (CISZ) core–shell quantum dots (QDs) afforded the C1@CISZ hybrid assembly. Comparative studies on the visible-light-induced H2 evolution performances of C1@CISZ and the non-bonded reference system comprising the unfunctionalized [Co(CR)Br2]+ complex (C2) and CISZ QDs (denoted as C2+CISZ) revealed that the photocatalytic activity of C1@CISZ was twice to thrice as high as that of C2+CISZ under the same conditions. Appealingly, the isolated C1@CISZ assembly was more stable than the C2+CISZ system in long-term photolysis. Moreover, photoluminescence (PL) and transient absorption (TA) spectroscopic studies demonstrated that covalent immobilization of C1 on the surface of CISZ QDs accelerated the electron transfer from QDs to the catalyst and meanwhile retarded the charge recombination process on the surface of QDs. The evidently improved charge separation efficiency resulted in the higher activity of the hybrid assembly C1@CISZ than that of C2+CISZ for photocatalytic hydrogen production.
关键词： photochemical H2 generation,cobalt complex,photocatalytic hydrogen production,CO2 reduction,charge transfer dynamics,CuInS2/ZnS quantum dots
更新于2025-09-16 10:30:52
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<i>Rhodopseudomonas palustris</i> -based conversion of organic acids to hydrogen using plasmonic nanoparticles and near-infrared light
摘要： The simultaneous elimination of organic waste and the production of clean fuels will have an immense impact on both the society and the industrial manufacturing sector. The enhanced understanding of the interface between nanoparticles and photo-responsive bacteria will further advance the knowledge of their interactions with biological systems. Although literature shows the production of gases by photobacteria, herein, we demonstrated the integration of photonics, biology, and nanostructured plasmonic materials for hydrogen production with a lower greenhouse CO2 gas content at quanti?ed light energy intensity and wavelength. Phototrophic purple non-sulfur bacteria were able to generate hydrogen as a byproduct of nitrogen ?xation using the energy absorbed from visible and near-IR (NIR) light. This type of biological hydrogen production has su?ered from low e?ciency of converting light energy into hydrogen in part due to light sources that do not exploit the organisms' capacity for NIR absorption. We used NIR light sources and optically resonant gold–silica core–shell nanoparticles to increase the light utilization of the bacteria to convert waste organic acids such as acetic and maleic acids to hydrogen. The batch growth studies for the small cultures (40 mL) of Rhodopseudomonas palustris demonstrated >2.5-fold increase in hydrogen production when grown under an NIR source (167 (cid:1) 18 mmol H2) compared to that for a broad-band light source (60 (cid:1) 6 mmol H2) at equal light intensity (130 W m(cid:3)2). The addition of the mPEG-coated optically resonant gold–silica core–shell nanoparticles in the solution further improved the hydrogen production from 167 (cid:1) 18 to 398 (cid:1) 108 mmol H2 at 130 W m(cid:3)2. The average hydrogen production rate with the nanoparticles was 127 (cid:1) 35 mmol L(cid:3)1 h(cid:3)1 at 130 W m(cid:3)2.
关键词： organic acids,near-infrared light,plasmonic nanoparticles,hydrogen production,Rhodopseudomonas palustris
更新于2025-09-16 10:30:52
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Soft-chemistry assisted strong metal-Support interaction on designed plasmonic core-shell photocatalyst for enhanced photocatalytic hydrogen production
摘要： Engineering photocatalysts based on gold nanoparticles (AuNPs) has attracted great attention for the solar energy conversion due to their multiple and unique properties. However, boosting the photocatalytic performance of plasmonic materials for H2 generation have reached some limitation. In this study, we propose a soft-chemistry method for the preparation of strong metal-interaction support (SMSI) to enhance the photocatalytic production of H2. The TiO2 thin overlayer covering finely dispersed AuNPs (forming an SMSI) boost the photocatalytic generation of hydrogen, compared to AuNPs deposited at the surface of TiO2 (labelled as a classical sytem). The pathway of the charge carriers’ dynamics occurred regarding the system configuration are found to be different. The photogenerated electrons are collected by AuNPs in a classical system and act as an active site, while, unconventionally, they are injected back in the titania surface for an SMSI photocatalyst making the system highly efficient. Additionally, the adsorption energy of methanol, theoretically estimated using density functional theory (DFT) methodology, is lower for soft-chemistry SMSI photocatalyst accelerating the kinetics of photocatalytic hydrogen production. SMSI obtained by soft-chemistry is an original concept for highly efficient photocatalytic materials, where the photons-to-energy conversion remains a major challenge.
关键词： hydrogen production,photocatalysts,solar energy conversion,gold nanoparticles,TiO2,SMSI
更新于2025-09-16 10:30:52
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Investigation of plasmonic Cu with controlled diameter over TiO2 photoelectrode for solar-to-hydrogen conversion
摘要： Plasmonic metal nanoparticles (NPs) have been used to improve the solar-to-hydrogen conversion efficiency. Relative to Au and Ag, Cu is cheaper and more abundant. In the present work, Cu NPs with the controlled diameter were deposited on TiO2 nanotube arrays (TNTAs) by using a pulse electrochemical deposition method. When the deposition was cycled 3600 times, the size of Cu NPs can be tuned to approximately 30 nm with the most uniform distribution, resulting in the remarkable characteristic peak of surface plasmon resonance and higher photocurrent density. The hydrogen production rates remained unchanged during irradiation (AM 1.5, 100 mW/cm2) of 2 h, indicating a good stability of the resultant Cu/TNTAs electrode. The photoelectrochemical performances of as-prepared Cu/TNTAs can also be comparable to those of Ag/TNTAs electrode fabricated by the same method.
关键词： TNTAs,Pulse electrochemical deposition,Hydrogen production,Stability,Plasmonic Cu
更新于2025-09-12 10:27:22
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Unsymmetrically pyrazole-3-carboxylic acid substituted phthalocyanine-based photoanodes for use in water splitting photoelectrochemical and dye-sensitized solar cells
摘要： A new photosensitizer, PCA-ZnPc-2, was synthesized through the asymmetric functionalization of phthalocyanine ring with a pyrazole-3-carboxylic acid as the electron-withdrawing and anchoring group and six hexylsulfanyl as the bulky electron-donating groups. PCA-ZnPc-2 was tested in dye-sensitized solar cells (DSSCs) and its performance was compared with PCA-ZnPc-1. It was found that PCA-ZnPc-2 has higher electron-donating ability which is favorable for light harvesting and suppress the dye aggregation on TiO2 when compared to PCA-ZnPc-1. Also, the new photosensitizer was used in dye-sensitized photoelectrochemical cells for hydrogen production under visible irradiation. The results show that PCA-ZnPc-2 is a promising photosensitizer to harvest the red/near-IR regions.
关键词： Dye-sensitized solar cells,Photoelectrochemical hydrogen production,Pyrazole-3-carboxylic acid,Phthalocyanine
更新于2025-09-12 10:27:22
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Ti3C2 MXene-derived carbon-doped TiO2 coupled with g-C3N4 as the visible-light photocatalysts for photocatalytic H2 generation
摘要： Photocatalytic hydrogen production is a fascinating clean energy technology to solve the environmental issues and energy crisis. Herein, Ti3C2, a member of MXene, is successfully designed as a precursor for preparing C-TiO2/g-C3N4 photocatalyst without extra carbon addition, and the C-TiO2/g-C3N4 photocatalysts exhibit drastically improved photocatalytic hydrogen generation activity. When the mass ratio of Ti3C2 to g-C3N4 is 10 wt% in the composite, the prepared C-TiO2/g-C3N4 composite photocatalyst shows the highest photocatalytic H2 production activity as high as of 1409 μmol/h/g, which is about 8 times and 24 times higher than the activity of pure g-C3N4 and C-TiO2, respectively. The possible mechanism is assumed that the achieved intimate heterojunction between the Ti3C2 MXene-derived C-doped TiO2 and g-C3N4 can efficiently facilitate the photogenerated charge transfer and inhibit the recombination of electronics and holes, which markedly enhanced photocatalytic hydrogen production activity of C-TiO2/g-C3N4 photocatalysts under visible light.
关键词： MXene,Carbon-doped TiO2,Photocatalyst,Hydrogen production,g-C3N4
更新于2025-09-12 10:27:22