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Photocatalytic and Antimicrobial Properties of Ag2O/TiO2 Heterojunction
摘要： Ag2O/TiO2 heterojunctions were prepared by a simple method, i.e., the grinding of argentous oxide with six different titania photocatalysts. The physicochemical properties of the obtained photocatalysts were characterized by diffuse-reflectance spectroscopy (DRS), X-ray powder diffraction (XRD) and scanning transmission electron microscopy (STEM) with an energy dispersive X-ray spectroscopy (EDS). The photocatalytic activity was investigated for the oxidative decomposition of acetic acid and methanol dehydrogenation under UV/vis irradiation and for the oxidative decomposition of phenol and 2-propanol under vis irradiation. Antimicrobial properties were tested for bacteria (Escherichia coli) and fungi (Candida albicans and Penicillium chrysogenum) under UV and vis irradiation and in the dark. Enhanced activity was observed under UV/vis (with synergism for fine anatase-containing samples) and vis irradiation for almost all samples. This suggests a hindered recombination of charge carriers by p-n heterojunction or Z-scheme mechanisms under UV irradiation and photo-excited electron transfer from Ag2O to TiO2 under vis irradiation. Improved antimicrobial properties were achieved, especially under vis irradiation, probably due to electrostatic attractions between the negative surface of microorganisms and the positively charged Ag2O.
关键词： Ag2O,antimicrobial properties,heterojunction,nanocomposites,heterogeneous photocatalysis,TiO2
更新于2025-09-23 15:22:29
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Handbook of Ecomaterials || Environmental Photocatalysis/Photocatalytic Decontamination
摘要： Water pollution caused by hazardous substances has become a global concern. Textile and dyestuff industries produce large amounts of wastewater containing various dye pollutants. Most azo dyes are nonbiodegradable and their release into the environment poses a major threat to the surrounding ecosystems. Remediation of organic aquatic pollutants by photocatalytic oxidation has proven to be an attractive promising technology among the advanced oxidation processes. Semiconductor photocatalysis is a topic of current interest mainly in view of its potential application in the mineralization of pollutants.
关键词： Pilot scale treatment,Heterogeneous photocatalysis,Air purification,Antimicrobial activity,Semiconductor oxides,Water pollution
更新于2025-09-23 15:21:21
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Heterogeneous photocatalysis: guidelines on experimental setup, catalyst characterization, interpretation, and assessment of reactivity
摘要： Soon after the publication of the first pioneering works on heterogeneous photocatalysis, the number of papers on this topic continuously increased. This intriguing field of research is very complex as it endows with an interdisciplinary overview that involves different aspects of chemistry, physics, material and environmental sciences. Even if photocatalytic applications in real processes are often difficult to be implemented and scaled-up, investigations at laboratory scale are easy to be performed, and in some cases they may give rise to misconceptions. For this reason, the present work aims to sum up most of the common experimental techniques and procedures generally used in heterogeneous photocatalysis and to highlight the guidelines and the rules that a rigorous analysis and study of a photocatalytic system must follow. The paper focuses on the importance of standardization of photocatalytic experiments with special attention on the possibility to compare results obtained under different experimental conditions.
关键词： engineering aspects,Heterogeneous photocatalysis,standardization,characterization techniques,experimental procedures
更新于2025-09-23 15:21:01
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Application of an electron-transfer catalyst in light-induced aerobic oxidation of alcohols
摘要： The first heterogeneous photocatalysis system including a bipyridinium-based complex as the electron-transfer catalyst was developed for aerobic oxidation of alcohols without the use of any noble-metal, external N-oxide or peroxide co-oxidant. The current work provides an efficient strategy for alcohol oxidation through a cost-effective, convenient and eco-friendly route.
关键词： bipyridinium complex,aerobic oxidation,heterogeneous photocatalysis,alcohols,electron-transfer catalyst
更新于2025-09-19 17:15:36
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Platform for molecular-material dual regulation: A direct Z-scheme MOF/COF heterojunction with enhanced visible-light photocatalytic activity
摘要： Series of novel metal-organic framework/covalent organic framework (MOF/COF) hybrid materials were constructed by encapsulating MOF with highly stable TTB-TTA (a COF synthesized from 4,4',4''-(1,3,5-triazine-2,4,6-triyl)tribenzaldehyde (TTB) and 4,4',4''-(1,3,5-triazine-2,4,6-triyl)trianiline (TTA)) layer, inheriting their merits of high crystallinity, large surface area, outstanding visible-light response and tunable band gaps. The introduction of NH2-MIL-125(Ti) into the hybrid materials could modulate their optical, electronic and redox properties, and promote the charge separation owing to the formation of heterojunction, thus resulting in an enhanced photocatalytic performance for organic pollutant decomposition. As such, NH2-MIL-125(Ti)/TTB-TTA composite has a much higher photodegradation kinetic of methyl orange (MO) which is over 9 and 2 times the rates of pure NH2-MIL-125(Ti) and TTB-TTA, respectively. This versatile molecular-material platform can achieve dual adjusting modes consisting of a COF molecular engineering and a MOF type screening strategy, which will be applicable to a wide range of fields.
关键词： metal-organic frameworks,covalent organic frameworks,heterogeneous photocatalysis,Z-scheme heterojunction,visible-light-driven
更新于2025-09-19 17:15:36
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Fabrication of Durable Ordered Ta2O5 Nanotube Arrays Decorated with Bi2S3 Quantum Dots
摘要： One of the most important challenges in the fabrication of ordered tantalum pentaoxide (Ta2O5) nanotube arrays (NTs) via the electrochemical method is the formation of nanotubes that adhere well to the Ta substrate. In this paper, we propose a new protocol that allows tight-fitting Ta2O5 nanotubes to be obtained through the anodic oxidation of tantalum foil. Moreover, to enhance their activity in the photocatalytic reaction, in this study, they have been decorated by nontoxic bismuth sulfide (Bi2S3) quantum dots (QDs) via a simple successive ionic layer adsorption and reaction (SILAR) method. Transmission electron microscopy (TEM) analysis revealed that quantum dots with a size in the range of 6–11 nm were located both inside and on the external surfaces of the Ta2O5 NTs. The effect of the anodization time and annealing conditions, as well as the effect of cycle numbers in the SILAR method, on the surface properties and photoactivity of Ta2O5 nanotubes and Bi2S3/Ta2O5 composites have been investigated. The Ta2O5 nanotubes decorated with Bi2S3 QDs exhibit high photocatalytic activity in the toluene degradation reaction, i.e., 99% of toluene (C0 = 200 ppm) was degraded after 5 min of UV-Vis irradiation. Therefore, the proposed anodic oxidation of tantalum (Ta) foil followed by SILAR decorating allows a photocatalytic surface, ready to use for pollutant degradation in the gas phase, to be obtained.
关键词： Bi2S3 quantum dots,ordered Ta2O5 nanotubes,heterogeneous photocatalysis
更新于2025-09-16 10:30:52
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Size-Controlled Synthesis of Pt Particles on TiO2 Surface: Physicochemical Characteristic and Photocatalytic Activity
摘要： Different TiO2 photocatalysts, i.e., commercial samples (ST‐01 and P25 with minority of rutile phase), nanotubes, well‐crystallized faceted particles of decahedral shape and mesoporous spheres, were used as supports for deposition of Pt nanoparticles (NPs). Size‐controlled Pt NPs embedded in TiO2 were successfully prepared by microemulsion and wet‐impregnation methods. Obtained photocatalysts were characterized using XRD, TEM, X‐ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET) specific surface area, DR/UV‐vis and action spectrum analysis. The effect of deposition method, amount of Pt precursor and TiO2 properties on size, distribution, and chemical states of deposited Pt NPs were investigated. Finally, the correlations between the physicochemical properties and photocatalytic activities in oxidation and reduction reactions under UV and Vis light of different Pt‐TiO2 photocatalysts were discussed. It was found that, regardless of preparation method, the photoactivity mainly depended on platinum and TiO2 morphology. In view of this, we claim that the tight control of NPs’ morphology allows us to design highly active materials with enhanced photocatalytic performance. Action spectrum analysis for the most active Pt‐modified TiO2 sample showed that visible light‐induced phenol oxidation is initiated by excitation of platinum surface plasmon, and photocatalytic activity analysis revealed that photoactivity depended strongly on morphology of the obtained Pt‐modified TiO2 photocatalysts.
关键词： titania morphology,microemulsion,platinum size,Pt‐TiO2,TiO2 particle size,heterogeneous photocatalysis
更新于2025-09-12 10:27:22
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Photocatalytic Activity: Experimental Features to Report in Heterogeneous Photocatalysis
摘要： Heterogeneous photocatalysis is a prominent area of research with major applications in solar energy conversion, air pollution mitigation, and removal of contaminants from water. A large number of scienti?c papers related to the photocatalysis ?eld and its environmental applications are published in different journals specializing in materials and nanomaterials. However, many problems exist in the conception of papers by authors unfamiliar with standard characterization methods of photocatalysts as well as with the procedures needed to determine photocatalytic activities based on the determination of “apparent quantum ef?ciencies” within a wavelength interval or “apparent quantum yields” in the case of using monochromatic light. In this regard, an astonishing number of recent research articles include claims of highly ef?cient (photo)catalysts or similar terms about materials with superior or enhanced ef?ciency for a given reaction without proper experimental support. Consequently, the comparison of the ef?ciencies of photocatalysts may result as being meaningless, especially when reports are only based on expressions determining (1) a reaction rate per weight of catalyst or its surface area, (2) quantum ef?ciencies or quantum yields, and (3) turnover frequencies or turnover numbers. Herein, we summarize the standards needed for reporting valuable data in photocatalysis and highlight some common discrepancies found in the literature. This work should inform researchers interested in reporting photocatalysis projects about the correct procedures for collecting experimental data and properly characterizing the materials by providing examples and key supporting literature.
关键词： photocatalytic activity,apparent quantum ef?ciency,photocatalytic ef?ciency,rate per weight,heterogeneous photocatalysis
更新于2025-09-10 09:29:36
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Metal Organic Frameworks Based Materials for Heterogeneous Photocatalysis
摘要： The increase in environmental pollution due to the excessive use of fossil fuels has prompted the development of alternative and sustainable energy sources. As an abundant and sustainable energy, solar energy represents the most attractive and promising clean energy source for replacing fossil fuels. Metal organic frameworks (MOFs) are easily constructed and can be tailored towards favorable photocatalytic properties in pollution degradation, organic transformations, CO2 reduction and water splitting. In this review, we ?rst summarize the different roles of MOF materials in the photoredox chemical systems. Then, the typical applications of MOF materials in heterogeneous photocatalysis are discussed in detail. Finally, the challenges and opportunities in this promising ?eld are evaluated.
关键词： solar energy,heterogeneous photocatalysis,metal-organic framework
更新于2025-09-10 09:29:36
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A true oxygen-linked heptazine based polymer for efficient hydrogen evolution
摘要： O-doped/functional g-CN polymers are promising material which has been reported to modify inherent electronic structure and light harvest ability of the g-C3N4 based photocatalysts. However, the doping position and concentration of hetero atom remains ill-defined although enhanced photocatalytic activity of modified g-CN photocatalysts has been reported. Herein, a facile two step procedure to synthesize heptazine polymer with defined O-atom position in polymer structure is presented. Cyameluric acid, a member of cyamelurine family upon polycondensation under inert atmosphere ensures the insertion of O-atom at bridge position between heptazine units in growing polymer. The developed polymer OLHP (oxygen linked heptazine polymer) attains high hydrogen production efficiency likely due to high O-content and efficient charge separation evident from PL spectra compared to g-CN. This heptazine based precursor design also eliminates the possibility of presence of triazine based moiety defects in g-C3N4 polymers.
关键词： Water splitting,Heterogeneous photocatalysis,Cyameluric acid,Heptazine,carbon nitride
更新于2025-09-10 09:29:36