- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Metal Sulfide Photocatalysis: Visible-Light-Induced Organic Transformations
摘要： Transition-metal sulfides belong to an important subgroup of semiconductor photocatalysts that could promote a variety of valuable redox reactions under mild conditions. One notable merit of metal sulfides is their relatively smaller bandgaps than metal oxides, which in turn make sure that many of them can directly utilize visible light. Historically, the deployment of metal sulfides for visible-light-induced organic transformations took place shortly after the genesis of the research field of heterogeneous photocatalysis. In this review, we primarily focus on recent state-of-the-art advancements of metal sulfide photocatalysis aimed at visible-light-induced selective organic transformations. Interests in this specific branch of photocatalysis have been rekindled due to the new methods for materials synthesis; the pursuit of new mechanisms; or the integration of metal sulfides with metal oxides, metal nanoparticles or other emerging materials. Thus we categorize them into four sections according to the different strategies in developing novel or more efficient organic processes. Binary and ternary metal sulfides, usually associated with new materials synthesis and mechanistic insights, can be used directly for visible-light-induced organic transformations. This is the basis of other further developments and will be introduced firstly. Next, the cooperation between metal sulfides and metal oxides or metal nanoparticles can be conducive to many photocatalytic systems. These developments will be discussed in the next two ensuing sections. Furthermore, the integration of metal sulfides with recent developed emerging materials such as metal-organic frameworks (MOFs), graphene and graphitic carbon nitride (g-C3N4) would be discussed in another section to highlight the importance of merging metal sulfides with these materials. We attempt to keep an impartial panorama of these four distinctive sections even though the phases of development are quite different among sections, leaving plenty of room for the future expansion of this burgeoning area.
关键词： Metal Sulfide,Selective Oxidation,Photocatalysis,Visible Light,Selective Reduction
更新于2025-09-23 15:23:52
-
Photocatalytic Degradation of Methylene Blue and Phenol Using TiO2/Activated-Carbon Composite Catalysts
摘要： Photocatalytic degradation of methylene blue and phenol were conducted separately in aqueous solutions using titania-activated carbon composites. Activated carbon composites of different textural features and light of different wavelength or energy were used in order explore their effects on the performance of titania-activated carbon catalysts. The catalysts (TiAC1, TiAC2 and TiAC3) were prepared by impregnating activated carbon supports with an aqueous suspension of titanium precursor (TiO2). The catalysts were characterized using BET, XRD and FTIR. The diffraction pattern showed strong peaks that are assigned to titanium anatase phase and weaker peaks that indicated low rutile phase. The FTIR showed broad peaks of Ti-O-Ti linkages in TiO2 particles. The photocatalytic degradation of methylene blue and phenol was performed separately in visible light and UV irradiation of different wavelengths. Adsorption was dominant in the case of methylene blue removal while photodecomposition was more pronounced in the case of phenol removal.
关键词： Photocatalysis,Phenol,Methylene blue,Titania,Activated carbon,Precursors
更新于2025-09-23 15:23:52
-
Solar Heterogeneous Photocatalytic Oxidation for Water and Wastewater Treatment: Problems and Challenges
摘要： Solar operation of heterogeneous photocatalytic oxidation reactors is looked at as a sustainable process for water and wastewater treatment, because it does not consume electric power and chemicals. However, there are still problems for technical-scale application. The problems addressed in this article are large area demand, water evaporation from open reactors and lack of simple photocatalyst recovery. An optimum solar reactor type is the parabolic compound collector reactor with borosilicate glass tubes. Challenges for further research are improvement in mass transfer as well as identification of novel photocatalysts which make use also of visible light, are efficient and stable, and are easy to be produced in an economically feasible way. Also the combination of photocatalysts with adsorbents is promising. Although membrane filtration processes have been successfully combined with solar photocatalytic oxidation and represent a safe barrier against spreading photocatalyst nanoparticles into the aquatic environment, more simple and less energy-consuming methods for photocatalyst recovery would be desirable.
关键词： Photocatalyst recovery,Novel photocatalysts,Solar photocatalytic oxidation,Photocatalysis adsorption hybrid process,Mass transfer
更新于2025-09-23 15:23:52
-
Fabrication and photocatalytic performance evaluation of hydrodynamic erosion–resistant nano-TiO2–silicone resin composite films
摘要： Herein, we present the preparation of nano-TiO2–silicone resin composite films by double liquid phase spray deposition. The films exhibit better adhesion stability and photocatalytic activity under a hydrodynamic erosion condition than conventional nano-TiO2 composite films. The TiO2 layer morphology and effective TiO2 coverage ratio (CR) were affected by the initial curing time (ICT) of the silicone resin, e.g., the increase in an ICT from 10 to 40 min resulted in a CR change from 79.1 to 98.7%. The surface morphology evolution of composite films was studied under a hydrodynamic erosion period of 4 weeks. Obtained results allowed the 4-week evolution to be divided into four stages (pitting, crack pregnant, banded stripping, and surface stripping periods), additionally revealed that the CR of all samples was remained above 65%. The photocatalytic activity of composite films before and after 4-week hydrodynamic erosion was evaluated by rhodamine B degradation experiments. The 4-week erosion only led to the decrease of the photodegradation efficiencies by less than 40% in all cases. Thus, the fabricated TiO2–silicone composite films demonstrated excellent durability and photocatalytic activity under the conditions of long-term hydrodynamic erosion, allowing one to conclude that this work paves the way to the fabrication of next-generation photocatalytic materials for industrial applications.
关键词： Photocatalysis,Film formation mechanism,Silicone resin,Photodegradation,Hydrodynamic erosion resistance,Nano-TiO2
更新于2025-09-23 15:23:52
-
Continuous Photocatalysis Based on Layer-by-layer Assembly of Separation-free TiO?/Reduced Graphene Oxide Film Catalysts with Increased Charge Transfer and Active-site
摘要： Although photodegradation is the most widely studied method for the purification of water, the challenges for the post-separation of catalysts from water prevent the technique from practical applications. In this study, separation-free TiO2/reduced graphene oxide (rGO) multilayer films were first prepared through layer-by-layer (LbL) assembly of TiO2 and graphene oxide (GO) on quartz slides, followed by a reduction of the assembled GO to rGO. For a proof-of-concept demonstration of novel continuous photocatalysis with potential for scale-up production, these quartz slides with TiO2/rGO film catalysts were further assembled into slide arrays in a home-made rectangular quartz reactor and a model pollutant Rhodamine B (RhB) solution was circularly pumped over the slide surface under UV irradiation. It was found that the as-prepared TiO2/rGO film catalysts show excellent enhanced continuous photocatalytic activity, with a photodegradation rate constant of 2.6 × 10-2 min?1 exceeding the corresponding TiO2/GO and TiO2 (TiO2/PSS) samples by a factor of 11.3 and 13, respectively. The enhanced performance is attributed to the formation of Ti-O-C bonds in film catalysts bridging TiO2 and rGO to enable efficient charge separation and transfer, the Ti-O-C bond bridged electron transfer leading to increase in ·O2- active sites on the rGO surface, and the porous-like multilayer structure. The recycling experiments showed the film catalysts are stable and could be reused with the same efficiency for at least 8 cycles.
关键词： layer-by-layer,continuous photocatalysis,separation free,graphene,film
更新于2025-09-23 15:23:52
-
Enhanced photocatalytic activity of TiO2/graphene by tailoring oxidation degrees of graphene oxide for gaseous mercury removal
摘要： We used a simple method of graphene oxide (GO) preparation with different oxidation levels, and control the properties of the TiO2 nanocrystals by tuning the content and oxidation degree of GO to enhance the photocatalytic performance. During the hydrothermal reaction, reduction of GO, formation of TiO2 and chemical bonds between TiO2 and reduced graphene oxide (RGO) was achieved simultaneously. Characterization results showed that TiO2 properties such as crystalline grain and particle size could be tailored by the amount of functional groups, and that crystallinity was also controlled by GO degrees of oxidation. TiO2/RGO photocatalysts showed great efficiency of mercury oxidation, which reached 83.7% and 43.6% under UV and LED light irradiation, respectively. The effects of crystalline grain size and surface chemical properties on Hg0 removal under LED and UV light irradiation were analyzed. In addition, the properties of the photocatalysts before and after UV illumination were investigated, finding that part of Ti-OH on TiO2 surface transformed to Ti-O-Ti. In a nutshell, this work could provide a new insight into enhancing activity of photocatalysts and understanding the photocatalytic mechanism.
关键词： TiO2,Photocatalysis,Chemical Bonds,Elemental Mercury,Reduced Graphene Oxide
更新于2025-09-23 15:23:52
-
Photocatalytic activity of biosynthesized CeO2 nano particles
摘要： This paper focuses on a cost effective and environment friendly technique for green synthesis of cerium oxide (CeO2) nano particles from cerium (III) nitrate hexahydrate solution by co-precipitation method using the leaf extract of different species of Artemisia pallens which acts as reducing and capping agent. The prepared CeO2 nano particles were characterized by XRD, TEM, FTIR, UV–Vis spectroscopy. The Photocatalytic activity of the prepared ceria powders was determined by their ability to degrade Methylene blue solution under UV-light radiation. The photo degradation result observed with 10 mg/L ceria at pH = 11 for 180 min have highest output and pseudo 1st order rate constant was 0.983.
关键词： Nanoparticles,Photocatalysis,Electronic material,Cerium oxide
更新于2025-09-23 15:23:52
-
Full spectrum responsive In2.77S4/WS2 p-n heterojunction as an efficient photocatalyst for Cr(VI) reduction and tetracycline oxidation
摘要： In the present work, wrinkled n-type WS2 nanosheets were synthesized and then used to construct the In2.77S4/WS2 p-n heterojunction photocatalyst. Experimental results reveal that the as-prepared hybrids present excellent photocatalytic activity for Cr(VI) reduction and tetracycline oxidation under visible and infrared light irritation. The photocatalytic efficiency of the as-prepared catalysts is found to increase initially followed by the decrease with the more weight content of WS2. When WS2 is up to 4 wt%, the as-prepared photocatalysts exhibit the highest photocatalytic activity, and are capable of reducing 99.1 % of Cr(VI) in 60 min and oxidizing 87.5 % of tetracycline in 20 min, much higher than 86.6 and 40.0 % of pure In2.77S4, respectively. This enhanced photocatalytic activity is attributed to the construction of In2.77S4/WS2 p-n heterojunction between p-In2.77S4 and n-WS2. The detailed clarification of photocatalytic mechanism is also elaborated in the paper.
关键词： In2.77S4,photocatalysis,heterojunction,WS2
更新于2025-09-23 15:23:52
-
Photocatalytic Degradation of Bisphenol A Induced by Dense Nanocavities Inside Aligned 2D-TiO2 Nanostructures
摘要： The preparation of materials with aligned porosity in the nanometer range is of technological importance for a wide range of applications in molecular filtration, biomaterials and catalysis. Herein we present the advantages offered by cryo – lyophilisation technique as a smart and green non-standard concept to produce dense regular polyhedral nanocavities inside the 2D TiO2 nanosheets. Hierarchical morphologies of nanocavities start to appear at temperature higher than 800 °C and are strongly influenced by polymorph TiO2 evolution competing reactions. The small angle X-ray scattering (SAXS) analysis confirms self-assembled 3D nanocavities with size range from 5 to 10 nm in both length and width, and depth ~ 3.6 nm formed after realising of the confined ice-water. It was found that nanocavities enhance significantly the absorption properties of TiO2 in the UV region, thereby providing a new approach to increase the photoreactivity of 2D TiO2 nanosheets. The annealed precursors containing aqueous solution of peroxo polytitanic acid (PPTA) at 800 °C exhibited the highest photoactivity in degrading bisphenol A (BPA) due to evenly distributed nanocavities inside single anatase TiO2 nanocrystals interconnected and aligned onto the 2D TiO2 nanosheet arrays.
关键词： emerging pollutants,nanoconfined water,photocatalysis,nanocavities,freeze-drying,anatase TiO2
更新于2025-09-23 15:23:52
-
In situ synthesis of visible-light-driven Z-scheme AgI/Bi2WO6 heterojunction photocatalysts with enhanced photocatalytic activity
摘要： In this work, an efficient visible-light-response AgI/Bi2WO6 heterojunction was successfully prepared via in situ precipitation of AgI nanoparticles on the aligned nanosheets of three-dimensional Bi2WO6 hierarchical microspheres for the first time. Studies suggested that the AgI/Bi2WO6 heterojunction exhibited excellent photocatalytic activity for tetracycline (TC) degradation compared to pure Bi2WO6 and AgI under visible light irradiation. Doping 20 wt% AgI resulted in the optimal TC photodegradation rate, which was 5.4 and 3.3 times higher than pure Bi2WO6 and AgI, respectively. The high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) verified that Ag nanoparticles generated on AgI/Bi2WO6 heterojunction surface in photocatalytic degradation process, which was beneficial for promoting the rapid combination of electrons on the conduction band of Bi2WO6 with the holes on the valence band of AgI and the separation and transfer of photogenerated electron-hole pairs. Accordingly, the nontraditional transport pathway of photogenerated electrons and holes based on the Z-scheme system that consisted of Bi2WO6, AgI, and Ag was confirmed. Based on the systematic experimental evidence, the possible enhanced photocatalytic mechanism was proposed.
关键词： Z-scheme,Photocatalysis,Heterojunction,AgI/Bi2WO6,Tetracycline
更新于2025-09-23 15:23:52