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MgO/g-C3N4 nanocomposites as efficient water splitting photocatalysts under visible light irradiation
摘要： A series of MgO/g-C3N4 nanocomposites was prepared by calcination of the mixture of magnesium nitrate hexahydrate and g-C3N4, and applied as photocatalysts for hydrogen evolution from water splitting. The results demonstrate that the MgO/g-C3N4 nanocomposites can effectively harvest sunlight to produce hydrogen from water with higher photocatalytic efficiency than the bare g-C3N4. A high hydrogen evolution rate (HER) of 30.1 μmol h-1 was achieved under visible light for the MgO/g-C3N4 composite loaded with 1 wt% MgO, which is much higher than that of the bare g-C3N4 (5.76 μmol h-1). The enhanced photocatalytic activity of the MgO/g-C3N4 composite could be attributed to the formation of heterojunction between g-C3N4 and MgO that promotes the photo-induced charge carriers' transmission and separation.
关键词： photocatalysis,MgO/g-C3N4 nanocomposite,heterojunction,hydrogen evolution
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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Highly efficient H2 production over NiCo2O4 decorated g-C3N4 by photocatalytic water reduction
摘要： Herein, ternary nickel cobalt oxide (NiCo2O4) was firstly employed to increase the photocatalytic water reduction ability of g-C3N4. 17.5wt%-NiCo2O4/g-C3N4 shows excellent water splitting performance with a H2 production rate of 5480 μmol·h-1·g-1, which is extremely better than that of Co3O4, NiO, Pt modified g-C3N4. The quantum efficiency of 17.5wt%-NiCo2O4/g-C3N4 can reach 4.5% under 400 (±7.5) nm light irradiation. The greatly increased activity of 17.5wt%-NiCo2O4/g-C3N4 can be attributed to the richer active sites and the superior electrical performance provided by co-existing nickel and cobalt ions with multivalent state. Moreover, the activity of composite almost shows no significant weaken even after 20 h irradiation. A Z-scheme route was put forwarded for H2 production over NiCo2O4/g-C3N4 instead of the traditional p-n junction based on our study.
关键词： NiCo2O4,bimetallic complex,photocatalysis,hydrogen evolution
更新于2025-09-23 15:23:52
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Fabrication of pyrimidine/g-C3N4 nanocomposites for efficient photocatalytic activity under visible-light illumination
摘要： In this work, a series of pyrimidine/g-C3N4 photocatalysts has been synthesized via a facile solvothermal method for the first time. The structure, elemental composition and morphology of the photocatalysts were characterized by FT-IR, SEM, XPS, N2 adsorption-desorption isotherms and BET characterization methods. The photocatalytic activity of the pyrimidine/g-C3N4 materials was investigated by the degradation of rhodamine solution under visible-light illumination. The pyrimidine/g-C3N4 photocatalyst with 1 wt% of pyrimidine shows the highest photocatalytic activity for the degradation of RhB, which can be mainly ascribed to the effective interfacial charge transfer within the pyrimidine/g-C3N4 photocatalyst and the cooperation effect of the excellent contact interface between g-C3N4 and pyrimidine. The main active species during the photodegradation process are determined by the radical trapping experiments, proving that the superoxide radical (?O2-) and the hydroxyl radical (?OH) play the main role in the photocatalytic reactions.
关键词： Photocatalysis,Pyrimidine,Charge transfer,g-C3N4
更新于2025-09-23 15:23:52
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Direct Z-scheme MoSe2 decorating TiO2 nanotube arrays photocatalyst for water decontamination
摘要： Exploring a Z-scheme heterojunction photocatalyst with efficient charge separation and outstanding redox ability is necessary but very challenging. Herein, a novel direct Z-scheme MoSe2 decorating TiO2 nanotube arrays photocatalyst (denoted as MoSe2@TNTs) was prepared by a facile in situ hydrothermal method. Few-layer MoSe2 nanosheets distribute on the surface of the TNTs without shielding the tubular structure. Compared with individual TNTs and MoSe2, the as-prepared MoSe2@TNTs composite displays much better photocatalytic activity for eliminating pollutants (such as 4-nitrophenol and hexavalent chromium). Investigation results reveal that TNTs combined with appropriate amount of MoSe2 as co-catalyst has direct Z-scheme construction instead of traditional type-II heterojunction, which can offer abundant photo-generated active species with high redox capacity.
关键词： Photocatalysis,TiO2 nanotube arrays,Z-scheme,Molybdenum diselenide
更新于2025-09-23 15:23:52
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In situ anion exchange strategy to construct flower-like BiOCl/BiOCOOH p-n heterojunctions for efficiently photocatalytic removal of aqueous toxic pollutants under solar irradiation
摘要： The poor charge separation of single-component semiconductor photocatalysts greatly restrains their practical application. Herein, we report an in situ anion-exchange strategy to controllably fabricate sunlight-driven p-n heterostructure photocatalyst BiOCl/BiOCOOH. In this synthetic process, the BiOCOOH microspheres not only act as the support to form heterostructures but also as Bi3+ supplier to generate BiOCl. Such an in situ anion-exchange route thus brought about the homogeneous distribution of BiOCl on the surface of BiOCOOH with tight interfacial contact. Under simulated solar illumination, the obtained BiOCl/BiOCOOH catalysts with p-n heterostructures show exceedingly superior photocatalytic activity against toxic pollutant (MO dye and TC antibiotic) to BiOCOOH and BiOCl. The optimal BiOCl/BiOCOOH, S3 sample has the highest photocatalytic activity with MO degradation rate constant of 0.0599 min?1, 2.9 or 9.7 folds higher than that of BiOCOOH or BiOCl. The alleviated charge separation and transfer as well as the flower-like structure mainly account for the enhanced performance. Radical scavenging experiments indicate that holes, ?OH and ?O2? collaboratively contribute to the degradation of pollutants. This work provides a novel sunlight-driven p-n heterojunction photocatalyst of BiOCl/BiOCOOH for wastewater treatment.
关键词： Anion exchange,Sunlight,BiOCl/BiOCOOH,Photocatalysis,p-n heterojunction
更新于2025-09-23 15:23:52
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2D ultra-thin WO3 nanosheets with dominant {002} crystal facets for high-performance xylene sensing and methyl orange photocatalytic degradation
摘要： Here we report the synthesis of two-dimensional (2D) ultra-thin WO3 nanosheets (~4.9 nm) with dominant {002} crystal facets through a facile surfactant-induced self-assembly method. It was found that the ultra-thin WO3 nanosheets showed remarkably enhanced xylene sensing performance and methyl orange photocatalytic degradation performance, which could be ascribed to the high percentage of reactive {002} crystal facets (>90%) and high specific surface area (121 m2/g). The mechanism of gas sensing and photocatalysis was systematically studied. This work will be intriguing for designing high-performance metal oxides-based gas sensing and photocatalytic materials through 2D structural modulation and crystal facets engineering, which is important to promote their practical applications in environmental issues.
关键词： {002} crystal facets,2D,Photocatalysis,WO3,Gas sensing
更新于2025-09-23 15:23:52
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Visible-light-initiated one-pot clean synthesis of nitrone from nitrobenzene and benzyl alcohol over CdS photocatalyst
摘要： The controlled visible-light mediated conversion of nitroaromatics to versatile nitrogen-containing intermediates is of great significance but still remains a challenge. Herein, we report for the first time a facile visible-light-initiated one-pot strategy for clean and efficient synthesis of nitrone from nitrobenzene and benzyl alcohol. It integrates the controlled photocatalytic reduction of nitrobenzene to phenylhydroxylamine by photogenerated electrons with the selective photocatalytic oxidation of benzyl alcohol to benzaldehyde by photoinduced holes over a low-cost CdS photocatalyst with a suitable reduction capability, followed by spontaneous condensation of the as-formed hydroxylamine and aldehyde at ambient pressure and room temperature. Furthermore, by modulating cocatalyst and illumination time, for the conversion of the same reactants, the other two useful nitrogen-containing compounds, imine and secondary amine, were also successfully synthesized. The reaction mechanisms for flexible synthesis of the three target products are proposed.
关键词： One-pot strategy,Clean synthesis,Photocatalysis,Nitrobenzene and benzyl alcohol,Nitrone,Imine and secondary amine
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
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Color removal from wastewater by photocatalytic process using titanium dioxide-coated glass, ceramic tile, and stainless steel sheets
摘要： Dye pollutants from textile industries are a major wastewater problem because they have complex chemical structures. Photocatalysis is a promising wastewater treatment method, which is used to remove dyes under light irradiation in the presence of a photocatalyst. In this article, titanium dioxide (TiO2) photocatalyst was synthesized through sol-gel technique and coated on different substrates (i.e. transparent glass, glazed ceramic tile, and stainless steel) by doctor blade technique. The coated substrates were used in an innovative reactor to remove colors in dye wastewater. The photocatalytic activities of the designed reactor were determined using a synthetic dye wastewater (methylene blue) under UV irradiations (36W-UVA or 30W-UVC lamps). The results showed that the optimum substrate yielded the highest color removal efficiency (93.03 ± 0.66%) was TiO2-coated glass under UVC irradiation. The recycling ability of TiO2-coated glass sheet was also evaluated. It was found that TiO2-coated glass sheet provided the same efficiencies for 20 cycles. In addition, the actual wastewater from textile industry was tested in this study with different pH values (i.e. pH = 3e11). The maximum color removal obtained was 87.86 ± 0.23% at pH value 11 on TiO2-coated glass under UVC irradiation. The color removal was found to decrease with decreasing pH.
关键词： Photocatalysis,Color removal,Wastewater treatment,Titanium dioxide,Dye wastewater
更新于2025-09-23 15:23:52