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Copper-doped hybrid Agx–Auy@ZnO nanoparticles and their enhanced photocatalytic activities
摘要： In this paper, we report on the simple polyol synthesis of copper-doped hybrid Agx–Auy@ZnO photocatalysts. The obtained samples have been characterized by X-ray diffraction, UV–Vis diffuse reflectance spectroscopy, transmission electron microscopy and an N2 adsorption study. The experiment results show that Ag, Au and Ag–Au alloy nanoparticles (NPs) successfully load onto the surface of the assembled Cu-doped ZnO. The photocatalytic performances of Cu-doped Agx–Auy@ZnO nanomaterials have been tested using diuron herbicide as a model contaminant under simulated solar light irradiation. The addition of Ag and/or Au nanoparticles to doped ZnO was strongly beneficial to the rate constant displaying a volcano-like pattern as a function of the Ag and Au content. A maximum pseudo-first-order rate constant of 18.55 × 10?3 min?1, 22.70 × 10?3 min?1 and 24.74 × 10?3 min?1 was achieved on Cu-doped Ag0.3@ZnO, Au0.5@ZnO and Ag0.5–Au0.3@ZnO respectively. The Cu-doped Ag0.5–Au0.3@ZnO bimetallic nanoparticles show the highest photocatalytic activity due to the synergistic effect by effective electron transfer.
关键词： Hybrid photocatalyst,Copper-doped,Diuron,Water treatment,Polyol process,One pot,Zinc oxide,Gold,Photocatalysis,Solar light,Silver
更新于2025-09-23 15:23:52
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Water-Stable Metal–Organic Frameworks with Selective Sensing on Fe <sup>3+</sup> and Nitroaromatic Explosives, and Stimuli-Responsive Luminescence on Lanthanide Encapsulation
摘要： Three water-stable luminescent MOFs [Zn4(bptc)2(NMP)3(DMF)(H2O)2]n (1-a), [Cd4(bptc)2(NMP)3(DMF)2(H2O)1]n (1-b), and {[Zn2(bptc)(DMA)(H2O)2]·(DMA)2·H2O}n (2), possessing similar chemical components (M2:L1:Sol3) and topology structures, were synthesized by solvents control. Their excellent sensing on iron(III) cation and nitroaromatic explosives (NACs) with great selectivity, sensitivity and a high Ksv (4.54 × 10^4 for 1-b on PNP) were observed by quenching effects. Furthermore, Zn-MOFs exhibit interesting stimuli-responsive luminescence enhancement after the encapsulation of a series of IIIB cations stimulated different luminescent emitting and intensity enhancement through host–guest processes of the pores in MOFs, especially for two distinct responses of Zn-MOF on a Tb3+ cation.
关键词： stimuli-responsive,nitroaromatic explosives,luminescent,water-stable,lanthanide encapsulation,iron(III),metal-organic frameworks,sensing
更新于2025-09-23 15:23:52
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ZnxCd1-xSe nanoparticles decorated ordered mesoporous ZnO inverse opal with binder-free heterojunction interfaces for highly efficient photoelectrochemical water splitting
摘要： Well-defined porous heteronanostructures with broad light absorption range and efficient charge transfer are the key challenges towards developing efficient photoanodes for photoelectrochemical (PEC) water splitting. Herein, we reported a facile template and continuous ion exchange method to fabricate three-dimensional ordered mesoporous (3DOM) ZnO/ZnxCd1-xSe inverse opal with binder-free heterojunction interfaces on F-doped SnO2 glass. The heteroepitaxial growth of ZnxCd1-xSe shell layer on ZnO inverse opal skeleton surface provided favorable type-II band alignment, low interfacial resistance, and high visible light absorption. As expected, the optimized 3DOM ZnO/ZnxCd1-xSe inverse opal achieved a significant saturated photocurrent density of 24.76 mA cm-2 at 1.23 V versus a reversible hydrogen electrode (RHE) in 0.25 M Na2S and 0.35 M Na2SO3 aqueous solution under AM 1.5 G simulated solar light irradiation (100 mW cm-2), which is 25 times higher than that of the pristine ZnO (0.99 mA cm-2 at 1.23 V versus RHE) photoanode. The maximum photoconversion efficiency reached 10.64% for the optimized 3DOM ZnO/ZnxCd1-xSe inverse opal at an applied potential of 0.52 V versus RHE, an about 22.63 times increase relative to that of the pristine ZnO inverse opal (0.47% at 0.61 V versus RHE). In addition, the photostability of the optimized 3DOM ZnO/ZnxCd1-xSe inverse opal photoanode was also greatly improved in the electrolyte solution, 82.6% initial value was maintained even after 3000 s continuous light illumination without any protective coating layer. Such prominent PEC performances of the as-prepared 3DOM ZnO/ZnxCd1-xSe inverse opal can be ascribed to the improved visible light harvesting and enhanced charge separation/collection efficiency. This work provides a fundamental insight to design the efficient photoanode for high performance water splitting.
关键词： Heteroepitaxial growth,ZnO/ZnxCd1-xSe,Inverse opal,Photoelectrochemical water splitting,Heterojunction interface
更新于2025-09-23 15:23:52
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Ultrathin 2D type-II p-n heterojunctions La2Ti2O7/In2S3 with efficient charge separations and photocatalytic hydrogen evolution under visible light illumination
摘要： In this work, novel 2D type-II p-n heterojunctions La2Ti2O7/In2S3 have been fabricated. The heterojunctions exhibit much improved photocatalytic activity over individual moieties and their physical mixtures in which 18-fold increment in hydrogen production has been achieved under visible light illumination (λ ≥ 400 nm). Their superior activities stem from intimate face-to-face contact between La2Ti2O7 and In2S3 in the heterojunctions which guarantee facile charge interchange. Photoelectrochemical analysis suggests that efficient charge separations occur at the interfaces of the heterojunctions and contributes to a prolonged charge lifetime as well as the much enhanced photocatalytic activities. Such a simple strategy by fabricating ultrathin type-II p-n heterojunctions also warrant promising applications in other areas such as optoelectronics, sensors etc. whereby efficient charge separations are needed.
关键词： charge separations,water splitting,type-II heterojunction,2D materials,photocatalyst
更新于2025-09-23 15:23:52
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Significant enhancement of photoactivity in one-dimensional TiO2 nanorods modified by S-, N-, O-doped carbon nanosheets
摘要： Titanium dioxide (TiO2) represents one of the most active photocatalysts among metal oxides for the degradation of pollutants and for solar water splitting to produce hydrogen. The most critical drawbacks hindering its broad practical use are the absorption majorly in the UV part of solar spectrum and slow charge dynamics. Combination of TiO2 with a suitable partner in a hybrid nanostructure can effectively address these drawbacks. Here we report a novel nanocomposite system based on one-dimensional TiO2 nanorods wrapped with a sulfur-, nitrogen-, and oxygen-doped carbon (SNOC) nanosheets. The SNOC nanosheets are synthesized by a cost-effective and facile route using eco-friendly carrageenan as a sulfur, oxygen, and carbon source and urea as a nitrogen source. Silica was used as the templating agent that leads to large surface area materials after its removal at the end of the synthesis. Therefore, the synthesized material exhibits superior photocatalytic performance for decoloring representative Rhodamine B (RhB) under visible light irradiation. SNOC shows the apparent rate constant of 7.6 × 10–3 min–1, which is almost 3 times higher than that of a SNOC material without using silica (2.8 × 10–3 min–1). This performance of doped carbon material can be assigned to the effect of large surface area and effective visible light adsorption. The TiO2 NRs / SNOC nanocomposite was investigated for photoelectrochemical water splitting showing much higher photocurrent densities (0.85 mA cm–2) than pure TiO2 nanorod arrays (0.35 mA cm–2), which was due to significant improvement in the charge transfer dynamics and co-catalytic effect of SNOC. All the materials prepared were evaluated on the basis of physical properties such as crystalline structure, optical absorption, surface topography, and electronic properties.
关键词： Water splitting,Photoelectrochemistry,Photocatalysis,Heterojunction,TiO2 nanorods,S, N, O-doped mesoporous carbon
更新于2025-09-23 15:23:52
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Porous WO3 monolith-based photoanodes for high-efficient photoelectrochemical water splitting
摘要： We report a successful fabrication of low-cost, high-efficient, structurally-rigid, porous WO3 photoelectrochemical (PEC) catalysts using polystyrene as the template by a sol-gel method and a high-temperature annealing treatment. The scanning electron microscopy and Brunauer-Emmett-Teller surface analysis results indicate that such WO3 monoliths possess a porous structure and a large specific surface area, which can supply lots of photogenerated charge transfer pathways as well as more surface PEC active sites. Compared with a commercially available WO3, our highly porous WO3 PEC catalysts show an excellent PEC water splitting activity. Particularly, the porous WO3 photoanodes calcinated in the presence of oxygen atmosphere at 450 °C for 7 h show the best PEC performance exhibiting the photocurrent density of 0.97 mA/cm2 at 1.23 V versus reversible the hydrogen electrode and the incident photon-to-current conversion efficiency up to 48.9% at 420 nm in 0.5 M Na2SO4 electrolyte under AM 1.5 G irradiation. Such excellent PEC performance is due to the high porosity of the WO3, promoting the fast transfer and the separation rate of photogenerated carriers during the PEC water splitting process.
关键词： Water splitting,Porous structures,Energy conversion,WO3,Photoanode
更新于2025-09-23 15:23:52
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Stoichiometric and non-stoichiometric tungsten doping effect in bismuth vanadate based photoactive material for photoelectrochemical water splitting
摘要： In photoelectrochemical (PEC) water splitting, BiVO4 has attracted attention due to its favorable band gap but it suffers low PEC performance due to poor conductivity. The vast majority of publications on this system has examined doping of stoichiometric composition of tungsten (W) on this system to increase bulk and interfacial conductivity while managing the contaminant generation of crystallographic defects and recombination sites. In this paper, a deep investigation was carried out to examine the effect of non-stoichiometric W doping in BiVO4 system. Stoichiometric and non-stoichiometric W-doped monoclinic BiVO4 (i.e. Bi1-(xtd)V1-xWxtdO4; BiV1-xWxtdO4 and BiV1-yWyO4; x ? 0.008; y ? 0.03 and d ? 0.005) were prepared using a facile dip coating technique. The stoichiometric composition contains charge balanced Bi, V and W atoms whereas non-stoichiometric compositions contain excess Bi and excess Bi and W. The non-stoichiometric composition BiV1-xWxtdO4 has shown better photoelectrochemical water splitting performance with respect to other compositions at 1.23 V vs RHE, under one sun illumination of electrode. The XRD and XPS results shows that non-stoichiometric doping with excess Bi or with excess Bi and W can possibly create an environment where V5t ions are substitutional replaced by W6t ions without generating other defects. But there was no signi?cant difference in band gap of different compositional samples observed. Further electrochemical impedance technique was used to analyze change in bulk and surface charge mobility with W-doping in BiVO4. The electrochemical impedance analysis showed the presence of low interfacial resistance, lower charge transfer resistance and high charge donor/surface state density for non-stoichiometric composition BiV1-xWxtdO4 electrode. It is evident from and cyclic voltammetry that the addition of excess Bi and W from its stoichiometric quantity ef?ciently suppressed the formation of hole-electron pair recombination sites. The electrochemical analytical results lead us to believe that the particular non-stoichiometric composition of BiV1-xWxtdO4 can signi?cantly lower trap sites and enhances kinetics of charge transfer, leading to the better photoelectrochemical water splitting performance.
关键词： Oxygen evolution,Photoelectrochemical cell,Water splitting,Bismuth vanadate,Tungsten doping
更新于2025-09-23 15:23:52
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Performance of a modified solar chimney power plant for power generation and vegetation
摘要： This paper develops a mathematical model to investigate the performance of a modified solar chimney power plant (MSCPP) for purposes of both power generation and vegetation. It then estimates the net added benefit. Results show that with the vegetation area enlarging, the MFR of the vapor increases, and more heat is used as the latent heat for water evaporation, leading to considerable reduction of the power. Condensation from the saturated air occurs only for very large vegetation area. On a cooler day, the plant produces less power and the condensation occurs for smaller vegetation area. Higher relative humidity of ambient air results in clear reduction of the MFR of the vapor evaporating from the vegetation area, and accordingly the great enhancement of the power. The benefit from agricultural products is larger than the benefit loss caused by the electricity loss, and the benefit of fresh water condensed from the saturated air is negligible. This leads to net added benefit for the MSCPP compared to the conventional plant. The net added benefit becomes greater with larger vegetation area. When the chimney is heightened from 1000 m to 1500 m, the power is enhanced greatly; however, the net added benefit becomes smaller.
关键词： Vegetation,Solar collector,Latent heat,Fresh water,Solar chimney,Power generation
更新于2025-09-23 15:23:52
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Investigation of effect of fresnel lens on the performance of double slope single basin solar still
摘要： The shortage of drinking water has become one of the biggest problems in the world. Water pollution increases considerably because of factors such as population growth, industrialization, urbanization, etc. Several new technologies have been invented for desalination from time to time and solar distillation is considered more economical. In this work, the influence of Fresnel lens on the conversion of the polluted water that is coming out from the industries into the drinking water was investigated using double slope single basin solar still. The industrial waste water (of pH value of 14) was used in the solar still and was converted into the drinkable water. The results show that the polluted industrial waste water can effectively be converted into drinkable water with the use of Fresnel lens.
关键词： double slope,Fresnel lens,solar still,desalination,water
更新于2025-09-23 15:23:52
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Photocatalytic overall water splitting on isolated semiconductor photocatalyst sites in an ordered mesoporous silica matrix: A multiscale strategy
摘要： Photocatalytic overall water splitting (OWS) in a stoichiometric ratio has attracted increasing attention for the realization of a sustainable, environmentally friendly future. However, this reaction exhibits sluggish kinetics due to efficiency limitations of the involved steps, including photon absorption, electron transfer, and the reactions that occur at triple-phase boundary regions. Herein, we report a general multiscale strategy to address this challenge by designing a model composite catalyst with a high loading density of isolated Bi0.5Y0.5VO4 nanocrystals, as building blocks, dispersed in a hexagonally ordered mesoporous silica matrix. In contrast to the well-recognized heterojunction formed between different semiconductors, we show that confined growth favours the formation of isolated quaternary solid-solution photocatalysts (Bi0.5Y0.5VO4), which can further interface with the insulating silica to overcome temperature limitations and exhibit enhanced photon absorption and electrochemical and mass transfer properties due to the transparent periodic porous structure of silica and the as-formed small nanocrystals with high crystallinity and a passivated surface. When the semiconductor photocatalyst is incorporated with the inert silica insulator, this nanoarchitecture does not inhibit the OWS activity but actually delivers a 10-fold higher OWS activity than bulk Bi0.5Y0.5VO4 prepared by the conventional solid-state method.
关键词： Multiscale strategy,Photocatalysis,Isolated solid-solution nanocrystal,Overall water splitting,Mesoporous composite
更新于2025-09-23 15:23:52