Plasmon assisted reactions on a metal surface occur through a different mechanism compared to traditional reaction conditions. Based on a SERS study of the model plasmon assisted reaction of PNTP to DMAB, we present the first regulation strategy for these reactions, enabled here, through the controlled adjustment of acidic properties.

A simple and effective method to prepare photocatalytically active electrodes for water oxidation is described in this paper. The precious-metal-free catalyst, Co4O4(O2CMe)4(4-vinylpy)4 (py = pyridine) was electrochemically polymerised on a RuP-sensitised TiO2 (RuP = [Ru(bpy)2(4,4′-(PO3H2)2bpy2)]Cl2) and on a TiO2 surface codecorated with vinyl phosphate (Vpa) and RuP for applications in molecular photoelectrochemical (PEC) devices. With a Vpa chain as the anchoring group, the photoanode poly-Co4O4+Vpa/RuP/TiO2 demonstrated a significantly higher PEC performance compared to poly-Co4O4/RuP/TiO2. The introduction of a Vpa chain allows better immobilisation of catalyst and enhances the electron transport between the photosensitiser and the catalyst. A photocurrent density of ∼100 μA cm−2 was achieved in a Na2SO4 solution at pH 7.0 under a 0.4 V external bias, with a faradaic efficiency of 76% for oxygen production.

Nanoframe catalysts containing only small amounts of precious metals show very high activities, and therefore have received great attention in recent years. In this work, we report an effective approach for the construction of light-harvesting systems to further enhance the catalytic activity of Pd nanoframes by encapsulating Au nanocrystals into the hollow interior of the nanoframes. Catalytic studies show that the as-prepared Au@Pd-frame nanocrystals can significantly enhance the catalytic activity of Pd nanoframes by a factor of 4.5 toward Suzuki coupling reactions under light irradiation.

Both dual responsive and thermal responsive reduced graphene oxide (rGO) with a strategically inbuilt function have been successfully synthesized by utilizing non-covalent modified poly(NIPAm-co-ViEtImBr) combined with anion exchange.

In this study, we focus on the impact of external electric fields on the light-induced charge transfer process in porphyrin–oligothiophene–fullerene triads. Density functional theory and visualization techniques were used to analyze the nature of the charge transfer excited states and to calculate the electronic coupling matrix, reorganization energy, free energy change, and other related data. Our simulated results reveal that, for this system, the efficiency of charge transfer is controlled by the external electric field. And the external electric field mainly affects the charge transfer integral. The mechanism of this ultrafast charge separation still needs for more in-depth researches.

•The intramolecular hydrogen bond is strengthened in the first excited-state.•The hydrogen bond facilitates the proton transfer from hydroxyl group to the neighbor N atom.•The spontaneous excited-state intramolecular proton transfer reaction can be observed.In the present work, TDDFT has been used to investigate the excited state intramolecular proton transfer (ESIPT) mechanism of a new chromophore II [Sensors and Actuators B: Chemical. 202 (2014) 1190]. The calculated absorption and fluorescence spectra agree well with experimental results. In addition, two types of II configurations are found in the first excited state (S1), which can be ascribed to the ESIPT reaction. Based on analysis of the calculated infrared (IR) spectra of O–H stretching vibration as well as the hydrogen bonding energies, the strengthening of the hydrogen bond in the S1 state has been confirmed. The frontier molecular orbitals (MOs), Hirshfeld charge distribution and the Natural bond orbital (NBO) have also been analyzed, which displays the tendency of the ESIPT process. Finally, potential energy curves of the S0 and S1 states were constructed, demonstrating that the ESIPT reaction can be facilitated based on the photo-excitation.

•ILs-polysomes exhibited excellent stability for the construction of an enzyme electrode.•Direct electron transfer was achieved between the enzyme and the electrode.•The enzyme electrode exhibited good electrocatalytic performance toward H2O2.Polymeric liposomes (denoted as ILs-polysomes) are a biocompatible and conductive nanomaterial, which was first utilised as the electrode material for immobilising and biosensing redox enzyme horseradish peroxide (HRP). The morphology and surface property of IL-polysomes was characterised and systematically compared with unpolymerised ionic liquid based liposomes (denoted as ILs-liposomes). Differing from IL-liposomes, IL-polysomes preserves their original morphology and bilayer membrane structure on glassy carbon (GC) electrodes due to the cross-linking of polymerised lipids, thus exhibiting excellent stability and specific biocompability. Because of the existence of imidazolium ionic liquid moieties on the outer surface, IL-polysomes displays a positive charge in aqueous solution, leading to oppositely charged HRP self-assembling onto the vesicles to form HRP/IL-polysomes/PVA/GC electrodes. Owing to the combined merits of ILs and liposomes, electron transfer between HRP-FeIII/FeII redox couples of immobilised enzymes and GC electrodes can be achieved. Therefore, HRP/IL-polysomes/PVA/GC electrodes exhibited good electrocatalytic performance toward the electrocatalysis of H2O2. Accordingly, IL-polysomes could act as an efficient charged platform for the self-assembled redox enzymes to realise direct electrochemistry. IL-polysomes have a promising application in the fabrication of third-generation electrochemical biosensors.

•The hydrogen bond between the hydroxyl and phenanthrene is strengthened.•The hydrogen bond facilitates the proton transfer from the hydroxyl group to the N atom.•The spontaneous excited-state intramolecular proton transfer reaction can be observed.The dynamics of the excited-state intramolecular proton-transfer (ESIPT) reaction of 10-hydroxybenzoquinoline (HBQ) in different solvents, have been investigated based on the time-dependent density functional theory (TD-DFT) in detail. Upon excitation, the intramolecular hydrogen bond between the hydroxyl and phenanthrene functionality is significantly strengthened in the S1 state, which can be used as a reasonable tendency for facilitating the ESIPT process. In addition, the calculated vertical excitation energies in the S0 state and S1 state reproduce the experimental UV–vis absorbance and fluorescence emission spectra well. Through calculating the fluorescence spectra of the HBQ chromophore, two outcomes for this chromophore were found in the S1 state, which demonstrates that the ESIPT process occurs. The potential energy curves have been calculated to account for the mechanism of the proton-transfer process in the excited-state. As a result, the barrierless ESIPT process can occur in the S1 state with proton transfer from the O atom to the N atom. And maybe the ESIPT process is easier in methanol solvent due to the higher potential energy difference.

•The intramolecular hydrogen bond is strengthened in the first excited-state.•The hydrogen bond facilitates the proton transfer from hydroxyl group to the neighbor N atom.•The spontaneous excited-state intramolecular proton transfer reaction can be observed.In the present work, the solvent dependent excited-state intramolecular proton transfer (ESIPT) dynamics of 1-morpholinylmethyl-2-naphthol (MN) in n-hexane and acetonitrile have been investigated, based on the time-dependent density functional theory, as well as IEFPCM model. The theoretical results obtained, including the primary bond lengths, bond angles, and IR vibrational spectra, predict the possibility of ESIPT in the S1 state for MN chromophore in n-hexane and acetonitrile. In the polar solvent, all the calculated results are consistent with the experimentally observed phenomena and the dual fluorescence emission mechanism is well explained. Furthermore, our theoretical study provides the understanding for the undetected fluorescence peak at about 389 nm of the MN chromophore in n-hexane, as the fluorescence emission from keto-MN product of post-ESIPT process. Upon optical excitation, the normal enol form is excited to the first excited state, following which the proton may be transferred along the route (O17–H⋯N) with a relative large energy barrier (1.93 kcal/mol) and generate the keto tautomer. However, the low energy barrier (0.26 kcal/mol) for proton back-transfer facilitates the conformation transition from the keto to enol form.

With the use of isothermogravimetrical analysis, the enthalpies of vaporization, ΔglHom(Tav), at the average temperature, Tav = 445.65 K, for the ionic liquids (ILs) 1-alkyl-3-methylimidazolium propionate [Cnmim][Pro](n = 4, 5, 6) were determined. Using Verevkin’s method, the difference of heat capacities between the vapor phase and the liquid phase, ΔglCpom, for [Cnmim][Pro](n = 2, 3, 4, 5, 6), were calculated based on the statistical thermodynamics. Therefore, with the use of ΔglCpom, the values of ΔglHom(Tav) were transformed into ΔglHom(298), 126.8, 130.3, and 136.5 for [Cnmim][Pro](n = 4, 5, 6), respectively. In terms of the new scale of polarity for ILs, the order of the polarity of [Cnmim][Pro](n = 2, 3, 4, 5, 6) was predicted, that is, the polarity decreases with increasing methylene. A new model of the relationship between the surface tension and the enthalpy of vaporization for aprotic ILs was put forward and used to predict the surface tension for [Cnmim][Pro](n = 2, 3, 4, 5, 6) and others. The predicted surface tension for the ILs is in good agreement with the experimental one.

A well-designed type of ultrathin carbon shell coating a silver core was prepared for the first time through an alternate adsorption and carbonization method. The obtained ultrathin carbon shell shows prominent advantages, including sufficient uniformity, better chemical stability than silica or alumina, biocompatibility, being free of pin-holes and low cost.

Hollow spheres with nanometer to micrometer dimensions have been of great interest in many areas of science and technology due to their special structure and properties such as large specific area, surface permeability and low density. In this work, hollow copper microspheres were employed as a catalyst to degrade dyes. The microspheres show good catalytic activities in degradation reactions of dyes and maintain their catalytic activity when reused multiple times. The reaction rate of eosin Y (EY) and methylene blue (MB) degradation was enhanced by 7.5–15 times by hollow copper microspheres compared with the control test. Copper is particularly attractive as a catalyst, since it is orders of magnitude cheaper than any noble metal; so the hollow copper microspheres are expected to play an important role in the fields of catalysis and environmental remediation.Graphical abstractHollow copper microspheres show good catalytic activities in degradation reactions of dyes and maintain their catalytic activity when reused multiple times. Copper is particularly attractive as a catalyst, since it is orders of magnitude cheaper than any noble metal.Highlights► Hollow copper microspheres were employed as a catalyst to degrade dyes. ► The microspheres maintain their catalytic activity when reused multiple times. ► Copper is orders of magnitude cheaper than noble metals.

In this paper, we report experimentally and theoretically a surface photocatalysis reaction of 4-aminothiophenol (PATP) to p,p′-dimercaptoazobenzene (DMAB) on Au, Ag, and Cu colloids. Surface enhanced Raman scattering (SERS) spectra of PATP on Au and Cu colloids are significantly different from the normal Raman spectrum of PATP powder. Quantum chemical calculations reveal that PATP on Au and Cu colloids is converted to DMAB by a surface photocatalysis reaction, and all the strongly enhanced Raman peaks are the symmetric Ag vibrational mode by surface plasmon. The pH value effects on surface photocatalysis reaction were also investigated experimentally. It is found that plasmon-assisted surface photocatalysis reaction can be efficiently controlled by different pH values. The possibility of protonation of PATP adsorbed on Au and Ag nanoparticles at pH 3 is investigated theoretically. The molecular mechanism is proposed for controlling surface photocatalysis reaction by pH values.

Hollow pyrrole-platinumpoly (PPy-Pt) complex spheres effectively catalyze the decomposition of hydrogen peroxide to form oxygen. The method used to synthesize the catalysts employs chemical polymerization of pyrrole with potassium hexachloroplatinate(IV) as oxidant and ZSM-5 molecular sieve as a hard template removable by dissolution. ZSM-5 molecular sieve used as template has the following merits: it can be easily removed, it is inexpensive and owing to micrometer size it shows a minimal aggregation. In addition, the use of the zeolite avoids the need for non-volatile surfactants which may be adsorbed onto the synthesized PPy-Pt complex spheres and interfere with their possible applications in catalysis. The new micron-sized hollow PPy-Pt complex spheres are produced simply and cost-effectively, and they can be expected to play an important role in wastewater treatment technologies. The synthetic method may represent a novel route to prepare hollow conductive polymer spheres doped by various metals for specific applications.

A very simple and novel method is devised to study the mechanism of phase transfer catalysis (PTC) for a nucleophilic substitution reaction between potassium thiocyanate and p-nitrobenzyl bromide (p-NB); the mechanism of the nucleophilic substitution reaction is illustrated by characterizing the interfacial dilational viscoelastic properties of the crown ether catalysts and intermediates, which are closely related to the interfacial behavior of the species in the PTC reaction. The results obtained from this study can be used to infer the mechanism of the nucleophilic substitution reaction that uses 18-crown-6 (18C6) and dibenzo-18-crown-6 (DB18C6) as phase transfer catalysts. This mechanism begins with formation of the intermediates [K · Crown ether]+ and [K · Crown ether]+SCN− through mutual collisions between crown ethers and KSCN in the aqueous phase near the interface. Then the complex, [K · Crown ether]+Br−, was obtained due to the collision between [K · Crown ether]+SCN− and p-NB in the organic phase near the interface and simultaneously the products were obtained.

A one-step facile synthesis is devised for preparation of well-dispersed Ag–Ni core–shell nanoparticles with uniform and intact shells. The process is performed by a reduction of silver nitrate and nickel nitrate with sodium borohydride in water-in-oil (W/O) microemulsions of water/polyoxyethylene (4) nonylphenol (OP-4) and polyoxyethylene (7) nonylphenol (OP-7)/n-heptane. Transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV–vis absorption are utilized to characterize the Ag–Ni core–shell nanoparticles. Furthermore, the effect of molar ratio of Ni2+ to Ag+ and dosage of Ni2+ and Ag+ on morphology of the core–shell nanostructure is also discussed in detail. The thickness of Ni layers on the surface of Ag nanoparticles could be controlled by the dosage of Ni2+ and Ag+. The Ag–Ni core–shell nanoparticles showed a high catalytic activity for degradation reaction of eosin Y. The product may also have many potential applications in optical, magnetic, biochemical, and biomedical fields. The synthetic method reported here suggests a very promising route for the preparation of bimetallic core–shell structures, which is a subject of intense interest.

A well-designed and new type of sensitive surface-enhanced Raman scattering (SERS)-active substrate is reported in the paper. The process, which is performed by using 5 Å molecular sieves as templates and final removal of the templates, has considerable virtue of enormously enlarging the amount of contact spots between every pair of particles due to the formation of inner planar nanostructures. First, the ammine complexes of silver ions appear to adsorb on the molecular sieves, then reduced and coalescenced to form closed silver layers, and the 5 Å molecular sieves are subsequently removed by using HF to produce nanostructure aggregations. It has the prominent advantages that the SERS peak intensity of the ∼1076 cm−1 band of 4-mercaptophenol (4-MPH) adsorbed on Ag nanoaggreates is about 60 and 30 times greater than when it is adsorbed on silver nanoparticles coated on a glass substrate or on commercially available 2 μm-sized silver (μAg) powders, respectively. The new SERS-active substrate is produced simply and cost-effectively, so it is expected to play a great role in the development of SERS-based analytical devices.

The dilational viscoelastic properties of interfacial films containing fibrous crystals were investigated by means of two methods: the interfacial tension response to sinusoidal area variations and the relaxation of an applied stress. The results obtained show that fibrous crystals (length > 50 μm) could increase the dilational modulus of interfacial films on a jet kerosene/water interface. The dilational modulus increased with time due to the increase of sedimenting quantities and decreased with concentration after 15 h of pre-equilibrium time due to the enhancement of particle exchange between the bulk and the interface. The nature of films containing solid particles strongly depends on their shape. The ethyl metal phosphates, which are short and rigid, may pack tightly at the interface and form long-range ordered structure. As a result, interfacial films containing ethyl metal phosphates had higher dilational modulus and showed more elastic behaviour. The results obtained by interfacial tension relaxation measurements show that there exist two main relaxation processes in all films: the fast relaxation process with a characteristic relaxation time of several seconds, which may correspond to the exchange of alkyl metal phosphates between the bulk and the interface, and the slower relaxation process with a characteristic relaxation time of several tens of seconds, which may correspond to the interparticle interaction. However, only the films containing ethyl metal phosphates have the third relaxation process, which is the slowest process with a characteristic time of several hundreds of seconds. This slowest process may correspond to the reorganization of whole interfacial film. Our results may be used to account for the ability of solid particles in stabilizing emulsions.

Experimental data are presented to show the influence of alkyl metal phosphates, Shengli resin fraction, and NaCl, on the shear viscosity of interfacial films and the stability of emulsions. It was found that the alkyl metal phosphates and the Shengli resin fraction could enhance the shear viscosity of interfacial films and the stability of emulsions. NaCl (0.01–0.03 mol L−1) could change the shear viscosity of interfacial films containing alkyl metal phosphates and the Shengli resin fraction. The shear viscosity of interfacial films containing ethyl iron phosphate and the Shengli resin fraction decreased with the increase of the concentration of NaCl. On the other hand, NaCl could decrease the stability of the emulsions.

Both dual responsive and thermal responsive reduced graphene oxide (rGO) with a strategically inbuilt function have been successfully synthesized by utilizing non-covalent modified poly(NIPAm-co-ViEtImBr) combined with anion exchange.

Nanoframe catalysts containing only small amounts of precious metals show very high activities, and therefore have received great attention in recent years. In this work, we report an effective approach for the construction of light-harvesting systems to further enhance the catalytic activity of Pd nanoframes by encapsulating Au nanocrystals into the hollow interior of the nanoframes. Catalytic studies show that the as-prepared Au@Pd-frame nanocrystals can significantly enhance the catalytic activity of Pd nanoframes by a factor of 4.5 toward Suzuki coupling reactions under light irradiation.

A well-designed type of ultrathin carbon shell coating a silver core was prepared for the first time through an alternate adsorption and carbonization method. The obtained ultrathin carbon shell shows prominent advantages, including sufficient uniformity, better chemical stability than silica or alumina, biocompatibility, being free of pin-holes and low cost.