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Resolving orbital pathways for intermolecular electron transfer
摘要： Over 60 years have passed since Taube deduced an orbital-mediated electron transfer mechanism between distinct metal complexes. This concept of an orbital pathway has been thoroughly explored for donor–acceptor pairs bridged by covalently bonded chemical residues, but an analogous pathway has not yet been conclusively demonstrated for formally outer-sphere systems that lack an intervening bridge. In our present study, we experimentally resolve at an atomic level the orbital interactions necessary for electron transfer through an explicit intermolecular bond. This finding was achieved using a homologous series of surface-immobilized ruthenium catalysts that bear different terminal substituents poised for reaction with redox active species in solution. This arrangement enabled the discovery that intermolecular chalcogen?iodide interactions can mediate electron transfer only when these interactions bring the donor and acceptor orbitals into direct contact. This result offers the most direct observation to date of an intermolecular orbital pathway for electron transfer.
关键词： electron transfer kinetics,Marcus equation,ruthenium catalysts,intermolecular interactions,orbital-mediated electron transfer
更新于2025-09-23 15:21:21
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[Interface Science and Technology] Graphene Surfaces - Particles and Catalysts Volume 27 || Graphene-Based Metal Particles
摘要： Graphene is considered a new member of the carbon materials family. Graphene is made solely of monolayers of sp2 hybridized carbon atoms densely ordered in a honeycomb crystal lattice, from which graphitic materials of various dimensions, e.g., zero-dimensional (0D) fullerenes, 1D nanotubes, and 3D graphite, can be built up. Graphene exhibits diverse electronic, thermal, and optical properties, including significant carrier mobility at room temperature (z10,000 cm2 V(cid:1)1 s(cid:1)1), theoretical specific surface area as high as 2630 m2 g(cid:1)1, and Young’s modulus as high as 1 TPa, along with superior thermal conductivity as high as 3000e5000 W mK(cid:1)1, resulting in its diverse potential applications in various fields such as chemical sensors, electronic devices, energy storage and conversion, catalysts, etc. Numerous endeavors have been being made to develop versatile and dependable physical and chemical fabrication techniques for the synthesis of graphene and its derivatives. So far, extensively utilized techniques, including chemical vapor deposition, epitaxial growth, thermal annealing approaches, the arc-discharge strategy, etc., have been successfully employed for the synthesis of graphene nanosheets (GNs) possessing great quality, mass production ability, and cost efficiency [1].
关键词： Catalysts,Metal Particles,Energy Storage,Graphene,Nanocomposites,Sensors
更新于2025-09-23 15:21:21
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Optical Control of Biomimetic Nanoparticle Catalysts Based Upon the Metal Component
摘要： Nanoparticle catalysts provide an intriguing route to achieving sustainable reactivity. Recent evidence has suggested that both the underlying metallic core and the passivating ligand layer can be exploited to control reactivity. The intimate interactions between the core metal and structure of the ligand layer can change based upon the metal used to generate the catalytic particle. Through judicious selection of both components, nanoparticle catalytic systems can be designed to be stimuli responsive for controlled reactivity. Herein we demonstrate the effects of the underlying metal on the optically modulated catalytic activity of peptide-capped noble metal nanoparticles. For this, a photoswitch was incorporated into the peptide that enables reversible reconfiguration of the bioligand overlayer structure between two conformations based upon the isomerization state of the photoswitch. These changes in activity are dependent upon the inorganic metal of the particle core, and we exploit this dependence to demonstrate changes in the activity. The materials were fully characterized via spectroscopic methods and microscopy to correlate the observed reactivity to the material composition. The results provide new pathways to achieve remotely responsive catalysts that could be important for controlled multistep reactions or be exploited for other applications including biosensing and plasmonic devices.
关键词： optically modulated catalytic activity,peptide-capped noble metal nanoparticles,biosensing,Nanoparticle catalysts,photoswitch,plasmonic devices
更新于2025-09-23 15:21:21
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The synthesis of graphene-TiO2/g-C3N4 super-thin heterojunctions with enhanced visible-light photocatalytic activities
摘要： In this paper, an efficient strategy for the synthesis of graphene nanobelt-titanium dioxide/graphitic carbon nitride (graphene-TiO2/g-C3N4) heterostructure photocatalyst was applied to fabricate a kind of visible-light-driven photocatalyst. The heterostructure shows higher absorption edge towards harvesting more solar energy compared with pure TiO2 and pure g-C3N4 respectively. Furthermore, the as-prepared graphene-TiO2/g-C3N4 heterostructure can show enhanced photocatalytic activity under visible-light irradiation. These outstanding performances of photocatalytic activities for graphene-TiO2/g-C3N4 composites can be attributed to the heterojunction interfaces which can separate the electron-hole pairs and impede the recombination of electrons and holes more efficiently. This study conclusively demonstrates a facile and environmentally friendly new strategy to design highly efficient graphene-TiO2/g-C3N4 heterostructure photocatalytic materials for potential applications under visible-light irradiation.
关键词： Visible light,Heterojunction,Nanostructured catalysts,Graphene,Photocatalytic activity
更新于2025-09-23 15:21:21
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Laser-Microstructured Copper Reveals Selectivity Patterns in the Electrocatalytic Reduction of CO2
摘要： The local (electro)chemical environment largely influences the selectivity toward, for example, olefins or alcohols in the electroreduction of CO2 over copper (Cu)-based catalysts. However, this factor is mostly qualitatively understood. Here, by combining catalytic results from a set of laser-microstructured Cu electrodes with defined geometries and accurate modeling including bulk and local effects, we map the effect of local pH and CO2 concentration for the main products. We also show how our results are useful for device engineering.
关键词： CO2 electroreduction,CO2 concentration,selectivity patterns,copper catalysts,laser-microstructured electrodes,local pH
更新于2025-09-23 15:21:01
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Ultrafast relaxation dynamics in bimetallic plasmonic catalysts
摘要： Combining a plasmonic metal, such as gold, with other popular catalysts, such as Ni or Pt, can extend its benefits to many energy-extensive reactions catalyzed by those metals. The efficiency of a plasmon-enhanced catalytic reaction is mainly determined by the light absorption cross section and the photo-excited charge carrier relaxation dynamics of the nanoparticles. We have investigated the charge carrier relaxation dynamics of gold/nickel (Au/Ni) and gold/platinum (Au/Pt) bimetallic nanoparticles. We found that the addition of Ni or Pt to gold can reduce light absorption in gold nanoparticles. However, electron–phonon coupling rates of Au/Ni and Au/Pt nanoparticles are significantly faster than that of pure Au nanoparticles. This is due to the fact that both Ni and Pt possess significantly larger electron–phonon coupling constants and higher densities of states near the Fermi level in comparison with Au. Additionally, the phonon–phonon coupling rate of bimetallic Au/Pt and Au/Ni nanoparticles was significantly different from that of pure gold nanoparticles, due to the acoustic impedance mismatch at the nanoparticle/substrate interface. Our findings provide important insights into the rational design of bimetallic plasmonic catalysts.
关键词： bimetallic nanoparticles,ultrafast relaxation dynamics,electron–phonon coupling,phonon–phonon coupling,plasmonic catalysts
更新于2025-09-23 15:21:01
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Visualizing pore architecture and molecular transport boundaries in catalyst bodies with fluorescent nanoprobes
摘要： The performances of porous materials are closely related to the accessibility and interconnectivity of their porous domains. Visualizing pore architecture and its role on functionality—for example, mass transport—has been a challenge so far, and traditional bulk and often non-visual pore measurements have to suffice in most cases. Here, we present an integrated, facile fluorescence microscopy approach to visualize the pore accessibility and interconnectivity of industrial-grade catalyst bodies, and link it unequivocally with their catalytic performance. Fluorescent nanoprobes of various sizes were imaged and correlated with the molecular transport of fluorescent molecules formed during a separate catalytic reaction. A direct visual relationship between the pore architecture—which depends on the pore sizes and interconnectivity of the material selected—and molecular transport was established. This approach can be applied to other porous materials, and the insight gained may prove useful in the design of more efficient heterogeneous catalysts.
关键词： porous materials,molecular transport,fluorescence microscopy,catalyst bodies,heterogeneous catalysts
更新于2025-09-23 15:21:01
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A Novel Single-Atom Electrocatalyst Ti <sub/>1</sub> /rGO for Efficient Cathodic Reduction in Hybrid Photovoltaics
摘要： Single-atom catalysts (SACs) are a frontier research topic in the catalysis community. Carbon materials decorated with atomically dispersed Ti are theoretically predicted with many attractive applications. However, such material has not been achieved so far. Herein, a Ti-based SAC, consisting of isolated Ti anchored by oxygen atoms on reduced graphene oxide (rGO) (termed as Ti1/rGO), is successfully synthesized. The structure of Ti1/rGO is characterized by high-angle annular dark-field scanning transmission electron microscopy and X-ray absorption fine structure spectroscopy, being determined to have a five coordinated local structure TiO5. When serving as non-Pt cathode material in dye-sensitized solar cells (DSCs), Ti1/rGO exhibits high electrocatalytic activity toward the tri-iodide reduction reaction. The power conversion efficiency of DSCs based on Ti1/rGO is comparable to that using conventional Pt cathode. The unique structure of TiO5 moieties and the crucial role of atomically dispersed Ti in Ti1/rGO are well understood by experiments and density functional theory calculations. This emerging material shows potential applications in energy conversion and storage devices.
关键词： reduced graphene oxide,titanium,single-atom catalysts,dye-sensitized solar cells,cathode reaction
更新于2025-09-23 15:21:01
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Porphyrins as Photoredox Catalysts in Csp2-H Arylations: Batch and Continuous Flow Approaches
摘要： We have investigated both batch and continuous flow photoarylations of enol-acetates to yield different α-arylated aldehyde and ketone building blocks by using diazonium salts as the aryl-radical source. Different porphyrins were used as SET photocatalysts, and photophysical as well as electrochemical studies were performed to rationalize the photoredox properties and suggest mechanistic insights. Notably, the most electron-deficient porphyrin (meso-tetra(pentafluorophenyl)porphyrin) shows the best photoactivity as an electron-donor in the triplet excited-state, which was rationalized by the redox potentials of excited states and the turnover of the porphyrins in the photocatalytic cycle. Scope, a two-step continuous protocol and multigram-scale reactions are also presented revealing a robust, cost-competitive and easy methodology, highlighting the significant potential of porphyrins as SET photocatalysts.
关键词： Diazonium Salts,Photoredox Catalysts,Porphyrins,Batch and Continuous Flow,Csp2-H Arylations
更新于2025-09-23 15:21:01
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Photo-controlled RAFT polymerization mediated by organic/inorganic hybrid photoredox catalysts: enhanced catalytic efficiency
摘要： Photo-controlled RAFT polymerization mediated by organic/inorganic hybrid photoredox catalysts: enhanced catalytic efficiency. Metalloporphyrins (MTPPs) play an important role in the conversion of light energy to initiate photo-induced electron transfer–reversible addition–fragmentation chain transfer (PET-RAFT) polymerization, in which zinc tetraphenylporphyrin (ZnTPP) has attracted a high degree of attention. However, the self-aggregation effect of porphyrins in some organic solvents such as dimethyl sulphoxide (DMSO) leads to quenching of the excited state of the MTPPs and reduces their photocatalytic capacity in a concentration-dependent manner. In this study, a ZnTPP–POSS organic/inorganic complex was fabricated by linking a polyhedral oligomeric silsesquioxane (POSS) to ZnTPP. The aggregation of the photocatalyst was efficiently depressed in a PET-RAFT polymerization which was catalyzed by ZnTPP–POSS under green light (λmax = 515 nm, 3 mW cm?2). Compared to ZnTPP, the reactions using ZnTPP–POSS as the photocatalyst were well controlled for different monomers with accelerated reaction rates. Well-defined block copolymers were successfully achieved by the chain-extension reaction which demonstrates the high-end fidelities of this polymerization approach.
关键词： Photo-controlled RAFT polymerization,PET-RAFT polymerization,organic/inorganic hybrid photoredox catalysts,block copolymers,ZnTPP–POSS
更新于2025-09-23 15:19:57