- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Rationally Designed Multifunctional Carbon-Palladium Nanohybrids for Wide Applications: From Electrochemical Catalysis/Nonenzymatic Sensor to Photothermal Tumor Therapy
摘要： Palladium nanomaterials have been widely investigated in many areas due to their high activity of catalysis and surface plasmon resonance (SPR) resulting from their special configuration of outer electron. Herein, the novel nanoparticles, reduced graphene oxide modified with palladium nanoflowers (rGO/PdNFs), were designed and synthesized by seeded growth. Their application potentials in three areas were explored, including electrochemical ethanol catalysis, nonenzymatic glucose sensor and photothermal tumor therapy. The hybrids of PdNFs and rGO increased the conductivity and active sites of PdNFs, and then enhanced the activity of catalysis. Interestingly, through control of morphologies, the absorption of PdNFs in near infrared region was enhanced compared with common palladium nanoparticles, which showed excellent potential in photothermal tumor therapy. These results indicated the stronger activity of catalysis to ethanol of rGO/PdNFs compared with the commercial Pd/C catalyst, superior sensitivity and selectivity of glucose, and effective photothermal antitumor efficacy. Overall, it is demonstrated that the multifunctional rGO/PdNFs nanohybrids could possess more application potentials.
关键词： Nonenzymatic sensor,Photothermal tumor therapy,Reduced graphene oxide,Palladium nanoflowers,Electrochemical catalysis
更新于2025-09-23 15:22:29
-
"Two-in-One" Strategy of o-Amino and Aromatic Nitrogen in Biomimetic Metal-Organic Frameworks for Efficient CO2 Photoconversion
摘要： Visible-light driven photoconversion of CO2 into energy carriers is highly important to the natural carbon balance and sustainable development. Herein, we demonstrate the biological nucleobase adenine-dependent CO2 photoreduction performance in green biomimetic metal-organic frameworks. Photocatalytic results indicate that AD-MOF-2 exhibited a very high HCOOH production rate of 443.2 μmol g-1 h-1 in pure aqueous solution, which is more than two times higher than that of AD-MOF-1 (179.0 μmol hour?1 g?1) in acetonitrile solution. Significantly, experimental and theoretical evidences reveal that CO2 photoreduction reaction mainly takes place on biological adenine molecules by unique o-amino assisted active aromatic nitrogen atom rather than traditional metal center. This work not only serves as an important case study for the development of green biomimetic photocatalysts used for artificial photosynthesis, but also proposes a new catalytic strategy for efficient CO2 photoconversion.
关键词： photosensitivity,hydrophobicity,biomimetic catalysis,green MOFs,artificial photosynthesis
更新于2025-09-23 15:22:29
-
European Microscopy Congress 2016: Proceedings || In-situ E(S)TEM Observations of Single Atom Dynamics in Catalytic Reactions
摘要： In heterogeneous catalysis, single-atom catalysts (SACs) take place at the atomic level at elevated temperatures. Understanding and control of complex catalytic reactions on the atomic scale are crucial for the rational development of improved catalysts and processes. The development of the first atomic-scale resolution environmental transmission electron microscopy (ETEM) is described (1-5), opening up new opportunities for studying gas-solid reactions in real time (6-9). The in-situ observations in ETEM have revealed the direct visualization of reaction intermediates and processes on the atomic scale in real time (1-5), offering insights into the dynamic behavior of catalysts and processes. The development of the ETEM (2) is now used globally. Benefits of the in-situ studies include new knowledge, improved and more environmentally beneficial catalytic technology as well as better or replacement mainstrain technologies in chemical and energy industries. Examples of the in-situ studies include new gold, improved and more environmentally beneficial catalytic technology as well as better or replacement mainstrain technologies in chemical and energy industries. The new insights have important implications for the application of nanomaterials in chemical process technologies including for transportation fuels, transformation fuels and in ammonia manufacture (6). Recently supported noble metal catalysts are examined for low temperature water-gas shift (WGS) catalysts (Fig. 1) and compared with reaction data and modeling. The in-situ observations in WGS have revealed the formation of clusters of only a few atoms from single-atom catalysts and the catalytic effect of low coordination sites. The new insights have important implications for the application of nanomaterials in chemical process technologies.
关键词： gas-solid reactions,environmental transmission electron microscopy,catalysis,single-atom catalysts,in-situ observations
更新于2025-09-23 15:22:29
-
Pyranopterin Related Dithiolene Molybdenum Complexes as Homogeneous Catalysts for CO <sub/>2</sub> Photoreduction
摘要： Two original dithiolenes, with a pyrazine ring fused with a pyran ring carrying the dithiolene chelate, mimicking molybdopterin (MPT) present in the active site of formate dehydrogenases (FDHs), have been synthesized. The first one mimicks MPT in the dihydropyrazine form while the second mimicks MPT in the more biologically relevant tetrahydropyrazine form. Both have been structurally characterized as a ligand within a cobalt(cyclopentadienyl)(dithiolene) complex. The corresponding MoO(dithiolene)2 complexes have been also prepared and are reported as the first functional and stable catalysts inspired by the Mo center of FDHs so far: they indeed catalyze the photoreduction of CO2 into formic acid, as the major product, and carbon monoxide, achieving more than 100 turnover numbers in about 8 h.
关键词： CO2 reduction,homogeneous catalysis,molybdenum complex,dithiolene ligands
更新于2025-09-23 15:22:29
-
Visible Light Driven Reductive (Cyclo)Dimerization of Chalcones Over Heterogeneous Carbon Nitride Photocatalyst
摘要： Single electron reduction of chalcones to the respective radical anions is a useful technique to activate these molecules toward subsequent transformations. Herein, a metal free photocatalytic version of chalcones reduction in the presence of triethanolamine as a convenient electron donor and using heterogeneous carbon nitride visible light photocatalyst is presented. The reaction proceeds via a long lived radical species of the heterogeneous organic semiconductor. The scope of the reaction was studied and regioselectivity of the chalcone radicals coupling was investigated. (1) Ten chalcones gave selectively poly substituted cyclopentanoles with 31-73% isolated yield; (2) Two chalcones bearing electron-donor groups, 4-MeOC6H4 and 2-thienyl, gave selectively the β-ketodienes in 42% and 53% isolated yield, respectively; (3) Pentafluorophenyl substituted chalcone gave exclusively the product of the radicals coupling followed by hydrogen transfer from triethanolamine – hexane-1,6-dione in 65% isolated yield. Reductive cross cyclodimerization of a mixture of two different chalcones proceeded regioselectively with the formation of one product out of four possible. The mechanism was investigated by cyclic voltammetry and linear sweep voltammetry and suggests that the reaction proceed through proton coupled electron transfer.
关键词： cyclopetanole,organic photoredox catalysis,chalcone,carbon nitride,proton coupled electron transfer
更新于2025-09-23 15:22:29
-
Enhancing Electron-hole Utilization of CdS Based on Cucurbiturils Vis Electrostatic Interaction in Visible Light
摘要： We synthesized a novel CdS/Cucurbit[n]urils (CB[n], n=5-10) composites by a simple one-step process. The CdS/CB[5] photo-catalyst exhibits excellent performance. In this context, CdS/CB[5] were studied by different chemical characterization techniques including fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) techniques. FT-IR and XPS indicate that the caged carbonyl port of CB[5] achieves substantial separation of CdS electron-holes. Furthermore, the concentration of hydroxyl radicals was monitored by fluorescence spectroscopy, which confirmed that the Cucurbit[n]urils can effectively enhance the photocatalytic reaction. We have checked the regeneration efficiency of CdS/CB[5], which was still at its higher value even after four cycles of recycling testing. Moreover, a reliable photocatalytic mechanism supported by fluorescent probe for degrading MB aqueous solution in the CdS/CB[5] composite was also described. We anticipate that the study of the mechanism of temporary interaction with holes can have a great impact on photo-catalysis theory.
关键词： methylene blue,CdS/CB[5],photo-catalysis,degradation
更新于2025-09-23 15:21:21
-
RECENT APPLICATIONS IN ORGANIC SYNTHESIS OF VISIBLE LIGHT PHOTOREDOX CATALYSIS
摘要： RECENT APPLICATIONS IN ORGANIC SYNTHESIS OF VISIBLE LIGHT PHOTOREDOX CATALYSIS. In the past few years, photoredox catalysis has become a powerful tool in the field of organic synthesis. Using this efficient method, it is possible to excite organic compounds from visible light and attain alternative mechanistic pathways for the formation of chemical bonds, a result which is not obtainable by classical methods. The rapid growth of work in the area of photoredox catalysis is due to its low cost, broad chemical utility protocols, and, especially, its relevancy from the green and sustainable chemistry viewpoints. Thus, this study proposes a brief theoretical discussion of and highlights recent advances in visible-light-induced photoredox catalysis through the analysis of catalytic cycles and intermediates.
关键词： visible light,photoredox catalysis,organocatalysis,organic synthesis,transition metals
更新于2025-09-23 15:21:21
-
Facile synthesis of NaOH-promoted Pt/TiO2 catalysts for toluene oxidation under visible light irradiation
摘要： NaOH-promoted Pt/TiO2 catalysts are successfully prepared by a facile impregnation method assisted by NaOH and tested for the toluene oxidation reaction under visible light irradiation. Keeping molar ratio of Pt:Na =1:8, the 0.1Pt-Na/TiO2 catalyst (0.1 mol% Pt) shows excellent catalytic performance with more than 60% of toluene conversion at 45 oC and achieving total toluene removal at 280 oC, which is significantly better than 0.1Pt/TiO2 catalyst. The structures and properties of catalysts are characterized by XRD, SEM, N2 adsorption, XPS and UV-vis spectra. The positively charged Pt species stabilized by NaOH are the most active sites for photo-thermal catalyzing toluene oxidation. The influence of Pt loading and the effect of supports (active TiO2 and inert Al2O3) are also discussed.
关键词： photo-thermal catalysis,toluene oxidation,TiO2,NaOH,Pt
更新于2025-09-23 15:21:21
-
Potassium-Promoted Reduction of Cu <sub/>2</sub> O/Cu(111) by CO
摘要： In situ X-ray photoelectron spectroscopy (XPS), infrared reflection absorption spectroscopy (IRRAS) and scanning tunneling microscopy (STM) were used to study the reduction of Potassium-modified Cu2O/Cu(111) by CO. By following the time evolution of the O 1s peak of Cu2O, we determined that the apparent activation energy for Cu2O reduction by 2 × 10-4 Torr CO is decreased by ~30% in the presence of K. On the K-modified surface, both XPS and IRRAS data show the formation of a surface species identified by IRRAS as carbonate (CO3 2-), likely forming a K+-CO3 2- complex, which is stable up to 500 K. STM images show that K+-CO3 2- complexes form chains around reduced Cu islands, thereby hindering the mass transfer of Cu atoms and preventing the reconstruction of the surface. Theoretical calculations show that the formation of carbonate on the K-modified ‘44’ Cu2O structure is thermodynamically favorable compared to the formation of CO2 on either the bare or K-modified surfaces.
关键词： STM,XPS,copper,catalysis,IRRAS,alkali promoter
更新于2025-09-23 15:21:21
-
Photocatalytic Oxyamination of Alkenes: Copper(II) Salts as Terminal Oxidants in Photoredox Catalysis
摘要： A photocatalytic method for the oxyamination of alkenes using simple nucleophilic nitrogen atom sources in place of prefunctionalized electrophilic nitrogen atom donors is reported. Copper(II) is an inexpensive, practical, and uniquely effective terminal oxidant for this process. In contrast to oxygen, peroxides, and similar oxidants commonly utilized in non-photochemical oxidative methods, the use of copper(II) as a terminal oxidant in photoredox reactions avoids the formation of reactive heteroatom-centered radical intermediates that can be incompatible with electron-rich functional groups. As a demonstration of the generality of this concept, it has been shown that diamination and deoxygenation reactions can also be accomplished using similar photooxidative conditions.
关键词： copper(II),photoredox catalysis,alkenes,oxyamination,terminal oxidant,photocatalytic
更新于2025-09-23 15:21:21