- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Photocatalysis as an advanced reduction process (ARP): the reduction of 4-nitrophenol using titania nanotubes-ferrite nanocomposites
摘要： TiO2 photocatalysis is an advanced process, employed worldwide for the oxidation of organic compounds, that leads to significant technological applications in the fields of health and environment. The use of the photocatalytic approach in reduction reactions seems very promising and can open new horizons for green chemistry synthesis. For this purpose, titanium dioxide nanotubes (TNTs) were developed in autoclave conditions using TiO2 P25 as a precursor material. Based on these nanotubular substrates, TiO2/CoFe2O4 (TCF) nanocomposites were further obtained by wet impregnation method. The materials were thoroughly characterized and their structural, textural, vibrational, optoelectronic and magnetic properties were determined. The composite materials combine absorbance in the visible optical range and high BET surface area values (~100 m2/g), showing extremely high yield in the photocatalytic reduction of 4-nitrophenol (4-NP), exceeding 94% within short illumination time (only 35 min). The developed nanocomposites were successfully reused in consecutive photocatalytic experiments and were easily removed from the reaction medium using magnets. Both remarkable recycling ability and high-performance stability in the photocatalytic reduction of nitrophenol were observed, thus justifying the significant economic potential and industrial perspectives for this advanced reduction process.
关键词： Cobalt ferrite,4-nitrophenol reduction.,Nanocomposite photocatalyst,TiO2 nanotubes
更新于2025-09-23 15:23:52
-
Ternary Ag nanoparticles/natural-magnetic SiO2-nanowires/reduced graphene oxide nanocomposites with highly visible photocatalytic activity for 4-nitrophenol reduction
摘要： Agglomerate and reuse limit the promising application of silver nanoparticles (AgNPs) as catalyst. To eliminate those disadvantages, herein, Fe-containing silica nanowires (SiO2NWs) and reduced graphene oxide (RGO) are used as suitable substrates to prepare AgNPs/SiO2NWs/RGO nanocomposite via self-assembly approach. The nanocomposite mostly assembled with each other via intermolecular hydrogen bond and electrostatic adsorption to form a three-dimensional network structure. The AgNPs/SiO2NWs/RGO nanocomposite exhibit excellent photocatalytic activity for 4-nitrophenol reduction by NaBH4, originating from that the nearly mono-dispersed AgNPs are adhered on the surface of the SiO2NWs and RGO, allowing the effective contact of reactants with catalyst and facilitating the electron transfer between them in the reaction. The obtained nanocomposites exhibit the superior stability and can be easily recovered with their fully catalytic activities due to the hydrophobic and magnetic properties of the nanocomposites. It shows the great prospect for the 4-NP reduction in practice and is promising for wide applications in visible light catalytic reaction.
关键词： SiO2 nanowires,Photo-catalytic activity,Reduced graphene oxide,Silver nanoparticles,4-Nitrophenol reduction
更新于2025-09-23 15:22:29
-
Semiconducting Metal Oxide Photonic Crystal Plasmonic Photocatalysts
摘要： Plasmonic photocatalysis has facilitated rapid progress in enhancing photocatalytic efficiency under visible light irradiation. Poor visible-light-responsive photocatalytic materials and low photocatalytic efficiency remain major challenges. Plasmonic metal–semiconductor heterostructures where both the metal and semiconductor are photosensitive are promising for light harvesting catalysis, as both components can absorb solar light. Efficiency of photon capture can be further improved by structuring the catalyst as a photonic crystal. Here, the synthesis of photonic crystal plasmonic photocatalyst materials using Au nanoparticle-functionalized inverse opal (IO) photonic crystals is reported. A catalyst prepared using a visible-light-responsive semiconductor (V2O5) displayed over an order of magnitude increase in reaction rate under green light excitation (λ = 532 nm) compared to no illumination. The superior performance of Au-V2O5 IO is attributed to spectral overlap of the electronic bandgap, localized surface plasmon resonance, and incident light source. For the Au-TiO2 catalyst, despite coupling of the LSPR and excitation source at λ = 532 nm, this is not as effective in enhancing photocatalytic activity compared to carrying out the reaction under broadband visible light, which is attributed to improved photon adsorption in the visible by the presence of a photonic bandgap, and exploiting slow light in the photonic crystal to enhance photon absorption to create this synergistic type of photocatalyst.
关键词： photonic crystal,nitrophenol reduction,catalyst,plasmonic nanoparticles,photocatalysis
更新于2025-09-23 15:21:01
-
Robot path planning with two-axis positioner for non-ideal sphere-pipe joint welding based on laser scanning
摘要： The conversion and degradation of organic pollutants remain challenges relating to environmental science. Herein, we report the carbonization of organic pollutants (4-nitrophenol, 4-NP) toward metal-free nitrogen-doped graphene quantum dots (N-GQDs) using a one-pot solvothermal route. The resultant N-GQDs demonstrate excellent activity for the catalytic conversion of 4-NP to 4-aminophenol (4-AP) when exposed to near infrared (NIR) light because of their excellent upconverted photoluminescence and photothermal conversion ability. The NIR-enhanced reduction efficiency of 4-NP to 4-AP not only originates from the enhanced collisions between N-GQDs and 4-NP due to photothermal-increased Brownian movement of molecules, but also comes from the accelerated transfer rate of electrons produced by the photoexcitation of N-GQDs under NIR irradiation. The N-GQDs display excellent photostability and remain high activity even after five cycles of reuse. Such conversion of organic pollutants to highly efficient metal-free carbocatalysts has significant importance in relevance of the industrial production of aniline and paracetamol.
关键词： organic pollutants,metal-free photocatalysts,4-nitrophenol reduction,nitrogen-doped graphene quantum dots,NIR-enhanced catalytic activity
更新于2025-09-19 17:13:59
-
Synthesis of graphene quantum dots stabilized CuNPs and their applications in CuAAC reaction and 4-nitrophenol reduction
摘要： Here we report the synthesis of graphene quantum dots (GQDs) stabilized copper nanoparticles in neat water. Construction of six CuNPs 1-6 nanocomposites are accomplished by mixing GQDs and NaBH4, and followed by the addition of different amounts of copper sulfate at 0 ℃ in water, respectively. Among them, CuNP-3, with the size of 2.6 nm, exhibits excellent catalytic performance in the CuAAC reaction over than other CuNPs. Moreover, the CuNP-3 has also been successfully applied for the reduction of 4-nitrophenol with excellent catalytic activity.
关键词： 4-Nitrophenol reduction,Copper nanoparticles,CuAAC reaction,Graphene quantum dots
更新于2025-09-19 17:13:59