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In this study, zinc aluminum layered double hydroxide (ZnAl-LDH) with a Zn/Al molar ratio 8/1 was synthesized via a facile urea method, and the mixed metal oxide (MMO) was prepared using the corresponding LDH as a precursor. In order to improve the performance of electron transport layer, we introduced graphene into ZnAl-MMO to prepare new nanocomposites, ZnAl-MMO/graphene, as promising photoanodes for dye-sensitized solar cell (DSSC). The bare ZnAl-MMO and formed ZnAl-MMO/graphene nanocomposites were characterized by X-ray diffraction (XRD), Raman spectra, scanning electron microscope (SEM) and UV–vis absorption spectrum, confirming the presence of graphene and the wurtzite type phase of ZnO. A series of DSSC were fabricated by the corresponding nanocomposites and a D205 as dye. The photovoltaic behavior of these cells based on different graphene concentration was further investigated by electrochemical method. It turned out that the introduced graphene facilitated the dye adsorption and light-scattering, which heightened the performance of DSSC. The DSSC based on ZnAl-MMO/0.2 wt.% graphene reached the best power conversion efficiency (PCE) of 0.51%, showing a rise of 25% approximately when compared with plain ZnAl-MMO.

Multiple-twinned silver nanoparticles (Ag-NPs) supported on mesoporous graphene were prepared through a facile oxidative etching process. Firstly, the Ag-NPs are supported onto the traditional graphene (Ag-NPs/G) by the typical wetness impregnation method. Then, the mesopores with sizes ranging from 5 to 10 nm were successfully fabricated on the initial graphene support through the oxidative etching process assisted by the Ag-NPs. And the Ag-NPs with multiple-twinned structure were simultaneously generated on the mesoporous graphene (Ag-MtNPs/MpG) during the etching process. The synergistic effect of both the unique mesopores on the graphene and the as-prepared multiple-twinned Ag-NPs in the Ag-MtNPs/MpG sample dramatically enhanced the release rate of silver ions (Ag+) and resulted in robust antibacterial activity of against Escherichia coli, in comparison with that of single crystallized Ag-NPs supported on traditional graphene (Ag-NPs/G). The present method paves a feasible way to design novel Ag based antibacterial materials.

We present an economical catalytic procedure to convert readily available 1,2-diaminobenzenes and terminal epoxides into valuable 1,2,3,4-tetrahydroquinoxalines in a highly enantioselective fashion. This procedure operates through relay zinc and iridium catalysis, and achieves redox-neutral and stereoconvergent production of valuable chiral heterocycles from racemic starting materials with water as the only side product. The use of commercially available reagents and catalysts and a convenient procedure also make this catalytic method attractive for practical application.

An integrated composite of meso-cellular silicate foam (MCF)-modified reduced graphene oxide (MCF@rGO) was designed and synthesized based on polyethylene oxide-polypropylene oxide-polyethylene oxide (P123)-modified rGO (P123-rGO). As the polymeric template for the fabrication of mesoporous silicates, modified P123 greatly improved the affinity between the nanosheet and the in situ formed MCFs, resulting in the formation of thin layers of MCFs on both sides of rGO. Therefore, the MCFs@rGO formed exhibited a unique sandwich structure with an inner skeleton of rGO and two outer layers of MCFs. The outer modification by MCFs, with the presence of large mesopores, not only shifted the surface property of rGO from hydrophobic to hydrophilic but also offered immobilized enzymes a favorable microenvironment to maintain their bioactivity. Meanwhile, the inner skeleton of rGO compensated for the weak conductivity of MCFs, providing a pathway for the direct electron transfer (DET) of various redox enzymes or proteins, such as hemoglobin (Hb), horseradish peroxidase, glucose oxidase (GOD), and cholesterol oxidase. It was found that the DET signal obtained from Hb-MCFs@rGO/glassy carbon electrode (GCE) was much larger than the sum of the signals from two components-based modified electrodes of Hb-P123-rGO/GCE and Hb-MCFs/GCE. A similar improvement in DET signal was also observed using GOD-MCFs@rGO/GCE. The significant enhancement of DET signals for both protein electrodes can be ascribed to the synergistic effects generated from the integration of the two components, one of which enhances biocompatibility and the other enhances conductivity. The bioelectrocatalytic performance of Hb and GOD electrodes was further investigated. As for Hb-MCFs@rGO/GCE, the GOD electrode displayed excellent analytical performance for the detection of hydrogen peroxide (H2O2), including a good sensitivity of 0.25 μA μmol-1 L cm-2, a low detection limit of 63.6 nmol L-1 based on S/N = 3, and a low apparent Michaelis-Menten constant (KMapp) of 49.05 μmol L-1. GOD-MCFs@rGO/GCE also exhibited good analytical performance for the detection of glucose, with a wide linear range of 0.25-8.0 mmol L-1. In addition, blood glucose detection in samples of human serum was successfully achieved using GOD-MCFs@rGO/GCE with a low quantification limit.

N-doped graphene (N-graphene) confined Pt nanoparticles (NPs) with core-shell structure supported on carbon nanotubes (CN@Pt/CNTs) are prepared by a facile two-step process. The obtained N-graphene nanoshell ranging from 2 to 4 graphene layers and the Pt NPs covered within N-graphene are uniformly dispersed on the CNTs. The as-prepared CN@Pt/CNTs exhibits much higher styrene selectivity and robust recycle ability in selective hydrogenation of phenylacetylene, compared with that of traditional CNTs supported Pt NPs (Pt/CNTs). DFT calculation reveals that the high styrene selectivity is derived from the confinement effect of N-graphene, which facilitates desorption of styrene from Pt NPs surface, avoiding the over hydrogenation of styrene to benzylethane. The present method paves a new way to design high selective Pt based hydrogenation catalyst.

Noble metal-semiconductor nanocomposites have received extensive attention in Surface Enhanced Raman Scattering (SERS) due to their unique properties. In this paper, the Ag–ZnO nanocomposites are prepared by hydrothermal growth and simple chemical reduction immersion. The synthesized nanocomposite material simultaneously integrates the individual enhancement effects of the two materials in the SERS, such as the electromagnetic enhancement of silver nanoparticles and the chemical enhancement of ZnO semiconductor materials. Using this substrate, Rhodamine 6G molecules with a concentration as low as 10−8 M can be detected, and the coupling reaction of PATP can be effectively promoted. The nanocomposite materials prepared by selecting appropriate semiconductor materials and metal materials combined, could be potentially applied, as SERS substrates, in certain catalytic reactions.

A new sensor for determination of Ag+ ion (Ag+) by surface-enhanced Raman scattering (SERS) is reported. Gold nanoparticles (AuNPs) and 4-aminodiphenyl disulfide (APDS) were chosen as the SERS substrate and probe molecule, respectively. With the addition of Ag+, three new peaks (1141, 1392, and 1435 cm−1) appeared in the SERS spectrum, indicating that the conversion of APDS to p,p′-dimercaptoazobenzene (DMAB) was achieved. As the concentration of Ag+ increased, the conversion of APDS to DMAB also increased and showed a good linear relationship (R2 = 0.9746) in the range of 10 to 100 μM of Ag+. The limit of detection (LOD) was 7 μM. Compared with the traditional determination method, the SERS method is convenient and fast and requires no complicated preprocessing.

A facile and efficient strategy is described in this communication for preparing a molecular catalyst/semiconductor hybrid photoanode by immobilizing a cobalt cubane water oxidation catalyst onto a porous BiVO4 electrode via electrochemical polymerization. With the introduction of Vpa as the anchoring linkage, the poly-1/Vpa/Al2O3/BiVO4 photoanode exhibits high performance as well as stability for photoelectrochemical water oxidation.

Radioiodine (129I and 131I) emission from the nuclear waste stream has aroused enormous apprehension because of its quick diffusion and radiological contamination. Conventional porous adsorbents such as zeolites and carbon with rigid skeletons and constant pore volumes reveal a limited performance for reliable storage. Here, a series of soft porous aromatic frameworks (PAFs) with additional π-conjugated fragments is disclosed to serve as physicochemical stable media. Due to the flexibility of the tertiary amine center, the PAF products provide sufficient space for the binding sites, and thus exhibit a considerable capability for iodine capture from both gaseous and soluble environments. The obtained capacity of PAFs is ca. 1.6 times higher than that of PAF-1 which possesses similar aromatic constituents featuring an ultra-large specific surface area (BET = 5600 m2 g−1). The novel paradigm of dynamic frameworks is of fundamental importance for designing adsorbents to treat environmental pollution issues.

PdZn alloy nanoparticles encapsulated within a few layers of graphene supported on ZnO nanowires (PdZn@C/ZnO) exhibit enhanced catalytic performance and robust long-term stability in semi-hydrogenation of acetylene to ethylene. The enhanced ethylene selectivity of PdZn@C/ZnO originates from the confining environment of the graphene cover, which can promote desorption of ethylene from the PdZn surface, avoiding the over-hydrogenation of ethylene to ethane.

An iridium-catalyzed diastereoselective amination of alcohols with chiral tert-butanesulfinamide was developed under basic conditions, affording the optically active secondary sulfinamides in high yields and diastereoselectivities. The removal of the sulfinyl group from sulfonamides allowed a facile access to a wide range of α-chiral primary amines. This synthetic strategy was further applied in the synthesis of the marketed pharmaceuticals (S)-rivastigmine and NPS R-568.

Modification of the semiconductor surface by cobalt-rich catalysts is an effective strategy to improve the photoelectrochemical (PEC) water oxidation kinetics and migration of photogenerated electr...

A new type of graphene-based catalyst with rewriteable function was designed and synthesized based on poly(1-vinyl-3-ethylimidazolium bromide) modified and reduced graphene oxide (denoted as poly[ViEtIm]Br-rGO). The modified polymeric ionic liquid poly[ViEtIm]Br not only acted as interlink between the polar catalytic anion and the non-polar graphene substrate, but also endowed the favorable dispersibility of poly[ViEtIm]Br-rGO in ionic liquid, leading to the adequate exposure of immobilized catalytic sites during the process of desulfurization. Moreover, due to the reversible anion-exchange property of the modified poly[ViEtIm]Br, various anions of Bronsted acids or heteropolyacids could be sequentially ‘written in’ or ‘erased’ on the nanosheets of rGO for desulfurization, thus establishing a green model for screening suitable catalysts based only on the limits of the same carrier. Such a rewriteable cycle was confirmed and monitored by characterization of TEM, FTIR spectroscopy and X-ray photoelectron spectroscopy (XPS). Based on this catalyst screening process of a rewriteable cycle, poly[ViEtIm][PW 12 O 40 ]-rGO, a heteropolyanoin modified rGO, was selected as the optimized catalyst. Benefiting from the synergistic effects between rGO and acidic anions, together with the large surface area and open two-dimensional structure of rGO, poly[ViEtIm][PW 12 O 40 ]-rGO was found to exhibit an excellent catalytic performance toward various sulfur-containing compounds. Furthermore, the outstanding reusability of poly[ViEtIm][PW 12 O 40 ]-rGO was also displayed owing to its structural stability. It was found that the sulfur removal efficiency of DBT could still reach 98.0% after the catalyst poly[ViEtIm][PW 12 O 40 ]-rGO had even been recycled eight times.

There is much evidence that surface plasmon photocatalytic reactions can occur on organic molecules on metal surfaces. In this paper, we focus on the photocatalytic reaction of 4-ethynylaniline (PEAN) on silver nanoparticles (Ag NPs) in a liquid environment by surface-enhanced Raman spectroscopy (SERS). Our experiments used SERS to characterize p,p′-diynylazobenzene produced from PEAN via a selective catalytic coupling reaction on Ag NPs. This discovery not only achieved the expected results but also broadens the known plasmon-driven surface catalytic reaction system. In our work, we also regulated the photocatalytic coupling reaction conditions of PEAN on Ag NPs by laser power-dependent and time-dependent SERS spectra.

In this study, we attempted to regulate the intermolecular distance of PNTP molecules on the surface of silver foil by breaking the S–S bond of NPDS. Though changing the laser wavelength and power, SERS conditions, the Raman spectra of NPDS and PNTP with different concentrations were compared. We found that, under SERS conditions, NPDS converted more efficiently than PNTP to DMAB at low-concentration with low-power and low-energy irradiation. The results indicate that the distance between molecules plays a significant role in the reaction of PNTP to form DMAB.

Photoelectrochemical (PEC) water splitting is a promising method for the conversion and storage of solar energy. A combination of catalysts with photoelectrodes is generally required for the development of active photoanodes in PEC devices. In this work, we present two BiVO4 photoanodes modified with cobalt salophen (Co(salophen)) complexes for PEC water oxidation. The resulting photoanodes show significantly enhanced PEC performance. Under simulated sunlight illumination (AM 1.5G, 100 mW cm−2), high photocurrents of 3.89 mA cm−2 and 4.27 mA cm−2 were obtained for Co1/BiVO4 and Co2/BiVO4, respectively at 1.23 V (vs. the reversible hydrogen electrode (RHE)) in a neutral solution, an almost three-fold enhancement over that of the unmodified BiVO4. Intensity-modulated photocurrent spectroscopy (IMPS) analysis shows that the Co(salophen) complexes not only accelerate the water oxidation reaction but also reduce the surface recombination. The half-cell solar energy conversion efficiencies for Co1/BiVO4 and Co2/BiVO4 were 1.09% and 1.18% at 0.7 V, respectively. Due to their hydrophobic nature, the Co(salophen) complexes can bind strongly to the surface of BiVO4. When the Co2 complex featuring four hydrophobic tert-butyl groups in a salophen ligand was anchored to BiVO4, an extremely stable photocurrent of more than 3.5 mA cm−2 at 1.23 V vs. RHE is sustained for at least 3 h without decay. Such a stable and robust photoanode based on a molecular WOC surpasses those attained by most of the state-of-the-art heterogeneous catalysts.

Constructing heterojunctions by coupling dissimilar semiconductors is a promising approach to boost charge separation and charge transfer in photoelectrochemical (PEC) water splitting. In this work, we fabricated a highly efficient TiO2/BiVO4 heterojunction photoanode for PEC water oxidation via a simple hydrothermal method. The resulting heterojunction photoanodes show enhanced PEC performance compared to the bare BiVO4 due to the simultaneous improvements in charge separation and charge transfer. Under simulated sunlight illumination (AM 1.5G, 100 mW cm−2), a high photocurrent of 3.3 mA cm−2 was obtained at 1.23 V (vs. the reversible hydrogen electrode (RHE)) in a neutral solution, which exceeds those attained by the previously reported TiO2/BiVO4 heterojunctions. When a molecular Co–cubane catalyst was immobilized onto the electrode, the performance of the TiO2/BiVO4 heterojunction photoanode can be further improved, achieving a higher photocurrent density of 4.6 mA cm−2 at 1.23 V, an almost three-fold enhancement over that of the bare BiVO4. These results engender a promising route to designing an efficient photoelectrode for PEC water splitting.

Aristolochic acid I (AAI) is a nephrotoxic chemical found in the plant genera, Aristolochia and Asarum. AAI can be reduced to positively charged aristolochyl actam-nitrogen ions in organisms: this intermediate product increases the oxidative stress due to AAI. Glutathione (GSH) acts synergistically with other amino acids in the liver for metabolizing toxic chemicals. Further, this small peptide containing an -SH group binds to AAI and reduces oxidative stress in A549 cells exposed to AAI. Surface-enhanced Raman scattering (SERS) was selected to explore the metabolites of the reaction between AAI and GSH. Ag@HSA was used as the basis for detecting metabolites based on its excellent biocompatibility. Moreover, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), and dynamic light scattering (DLS) were used to characterize the prepared SERS support substrate. A luminescence experiment was used to detect metabolites based on their chemical characteristics. In vivo tests in nude mice showed that AAI displays high toxicity. An injection of 200 μL AAI (10−4 M) into the abdominal cavity caused rapid death. CCK-8 assays showed that the viability of cells increased after adding GSH, indicating that GSH is involved in the detoxification metabolism of AAI.

We have developed a label-free, concise, time-efficient, ultrasensitive, and selective strategy for the determination of Fe2+ ion based on surface-enhanced resonance Raman scattering (SERRS) spectroscopy. There was no Raman signal because of the weak adsorption of 2,2′-bipyridine (Bpy) on silver nanoparticles (AgNPs). Upon the addition of Fe2+, Bpy quickly formed [Fe(Bpy)3]2+ complexes with Fe2+ and produced an intense Raman signal through inducing the aggregation of AgNPs, which provided a theoretical foundation for quantitative analysis of Fe2+. The proposed SERRS platform displayed a wide linear range from 10–11 to 10–7 M with an unprecedented detection limit of 5.73 pM. The whole process can be completed in 3 min and provided a new universal route for practical detection in various water samples.

A series of ionic liquids based on trifluoroacetic acid, namely, [Cnmim][TFA] (n = 2, 3, 4, 5, 6) (1-alkyl-3-methylimidazolium trifluoroacetate), were designed and synthesized. The density, surface tension and refractive index were measured in the temperature range of 293.15 to 343.15 ± 0.05 K, and some physicochemical properties of the ILs were calculated. Using the concept of molar surface Gibbs free energy, the traditional Eotvos equation was improved into a modified Eotvos equation, in which the intercept and the slope represented the molar surface enthalpy and the molar surface entropy, respectively, for [Cnmim][TFA] (n = 2, 3, 4, 5, 6). The thermal expansion coefficient (α) of [Cnmim][TFA] was calculated according to the interstitial model, and the order of magnitude of the calculated values was in good agreement with the corresponding experimental values. A new hypothesis was proposed, stating that the interstitial molar surface Gibbs free energy (gs) is not determined by the type of IL. From the refractive index and the molar surface Gibbs free energy, an equation to predict the surface tension of ILs was derived and the predicted values were highly correlated with the corresponding experimental values. Finally, a new polarity scale for ILs was developed, and the polarity order of the [Cnmim][TFA] (n = 2, 3, 4, 5, 6) ILs was estimated.

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.

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-Fe(III)/Fe(II) 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.

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 application of surface plasmon resonance (SPR)-assisted catalysis to synthesize aromatic azo compounds was first reported in 2010. The feasibility of SPR-assisted catalytic decomposition of aromatic azo compounds has also been confirmed, both experimentally and theoretically. Compared with traditional chemical synthesis methods, SPR-assisted catalysis has many advantages, such as high efficiency, low energy consumption, and high selectivity. The synthetic route to aromatic azo compounds and the kinetics thereof can be efficiently monitored by Raman spectroscopy. In this way, it has been confirmed that SPR-assisted catalysis occurs on the surface of noble metal nanoparticles (NPs). Mechanistically, the process involves transfer of electrons excited by the incident laser from noble metal NPs to 3O2 in air to form 2O2 − for the generation of SPR on the surface of the noble metal nanoparticles. The 2O2 − can then react with the metal to form metal oxides or hydroxides, which in turn can react with the substrate molecule. The substrate molecule can gain a proton from a proton donor or lose a proton to form a radical, which can react further. This mechanism accounts for the conversion of 4-aminothiophenol (PATP) into 4, 4-dimercaptoazobenzene (DMAB). The metal oxide or hydroxide formed reacts with PATP in an acid-base neutralization process. PATP radicals (PATP · ) are formed by the loss of a proton, and pairing of two PATP · leads to the intermediate product DMHAB. Deprotonation DMHAB then gives the final product DMAB.

In this work, a series of zinc titanium mixed metal oxides obtained from the zinc titanium layered double hydroxides as precursor were prepared as the photoanode material of the CdS quantum dot-sensitized solar cells. CdS quantum dots were deposited on photoanodes by the successive ionic adsorption and reaction method. It was investigated that the effects of photoanode based on different Zn–Ti molar ratios on the photovoltaic performance of solar cells. The essential parameters of samples were investigated by UV–vis absorption spectrum, incident photon-to-current conversion efficiency, photoelectric conversion efficiency and electrochemical impendence spectrum. The varying Zn–Ti ratios influence adsorption properties and charge mobility. As a result, the cells based on Zn–Ti MMOs achieved an optimum power conversion efficiency of 2.71% when the Zn–Ti ratio is 7:1.

Constructing a heterojunction photoelectrode is an effective way to promote the photogenerated charge separation in photoelectrochemical (PEC) water oxidation. In this work, we successfully fabricated C3N4/BiVO4 hybrid electrodes by integrating g-C3N4 onto the nanoporous BiVO4 via a simple in-situ synthesis method. The as-prepared C3N4/BiVO4 photoanodes were systematically studied by Electrochemical Impedance Spectroscopy, steady-state surface photovoltage (SPV), transient SPV, Open circuit potential and Photoluminescence measurements. With an optimal loading of g-C3N4, the 2-C3N4/BiVO4 electrode showed a high photocurrent density of 4.06 mA/cm2 at 1.23 V (vs. RHE) for water oxidation, a 2.8 times enhancement over that of the BiVO4. It is found that g-C3N4 improved the PEC performance of the photoanodes by simultaneously promoting the charge separation and surface reaction kinetics. When a NiOOH co-catalyst was immobilized onto the 2-C3N4/BiVO4 electrode, both the PEC property and stability of the photoanode were enhanced. An extremely high photocurrent density of 5.44 mA/cm2 at 1.23 V was achieved. The largest half-cell solar energy conversion efficiency for NiOOH/2-C3N4/BiVO4 was 1.43% at 0.78 V, corresponding to 8.4 times that of unmodified BiVO4 (0.17% at 0.97 V). This work brings new insight into the development of C3N4-based devices for application in solar to fuel conversion.

The surface passivation strategy is one of the effective ways to improve the power conversion efficiency (PCE) of quantum dots-sensitized solar cells (QDSSCs). In this work, a novel ZnS/SiO2 coating serves as the passivation layers for the CdS/CdSe co-sensitized solar cells based on zinc titanium mixed metal oxides (MMOs) obtained from layered double hydroxides (LDHs) precursor. The incorporation of passivation layers effectively improved the performance of the corresponding CdS/CdSe quantum dots co-sensitized solar cells and the best PCE of 4.91% has been achieved, which represents an over 55% improvement than that of devices without passivation. The effects of ZnS/SiO2 double passivation layers were systematically investigated, especially by 2D time-resolved fluorescence imaging and electrochemical impedance spectroscopy technique. It was revealed that the existence of ZnS/SiO2 outer layers caused the suppression of charge recombination, higher electrons collection efficiency, and superior surface quality.

Two aromatic compounds, l -phenylalanine and l -tyrosine, are used to study the role of phenyl rings in SERS. Through the interaction of benzene ring and silver sol, it is found that the signal of SERS is greatly enhanced compared with conventional Raman. The effects of sodium borohydride, anti-destructive thrombosis, formaldehyde, tannic acid, and sodium citrate as a reducing agent on silver sol was prepared by reducing AgNO3, on SERS with amino acid were studied. It was found that the silver sol prepared by reducing sodium nitrate by sodium borohydride had the best reinforcing effect.

In general, a colloidal method employing polyvinylpyrrolidone (PVP) as the stabilizer has been proven particularly suitable for preparing Pd nanoparticles (Pd-NPs) with controlled morphology and size. However, this surfactant will seriously cover the Pd-NP surface, which is detrimental for catalytic activity. In this paper, we reported a method to remove PVP from the carbon nanotube (CNT) supported Pd nanocubes (Pd-NCs) and Pd nanooctahedra (Pd-NOs) by steam treatment in a lab-made reactor. We found that this method can not only efficiently remove PVP from the Pd-NP surface, but also can well maintain the original structure of Pd-NCs and Pd-NOs, dramatically enhancing the catalytic performance. The present approach may promote potential applications of Pd-NPs prepared by colloidal methods in catalytic fields.

4-Aminothiophenol (PATP) and 4-aminophenyl disulfide (APDS) in contact with silver will form H2N-C6H4-S-Ag (PATP-Ag), and under the conditions of surface-enhanced Raman spectroscopy (SERS), a coupling reaction will generate 4,4-dimercaptoazobenzene (DMAB). DMAB is strongly Raman-active, showing strong peaks at ν ≈ 1140, 1390, and 1432 cm–1, and is widely used in surface-plasmon-assisted catalysis. Using APDS, PATP, p-nitrothiophenol (PNTP), and p-nitrodiphenyl disulfide (NPDS) as probe molecules, Raman spectroscopy and imaging techniques have been used to study the effect of intermolecular distance on surface-plasmon-assisted catalysis. Theoretically, PATP-Ag formed from APDS will be bound at proximal Ag atoms on the Ag surface due to S–S bond cleavage. The results show that APDS is more prone to surface-plasmon-assisted catalytic coupling due to the smaller distance between surface PATP-Ag moieties than those derived from PATP. Therefore, APDS has a higher reaction efficiency, better Raman activity, and ...

Formal regiodivergent C–H alkynylation of 1-aryl-5-pyrazolones has been realized under the catalysis of Rh(III) and Au(I) complexes by using a hypervalent iodine reagent as the alkyne source. Mechanistic studies indicate that the regioselectivity is ascribed to not only the choice of the catalyst but also the nature of the substrate. The substrate scope and functional group compatibility have been fully examined.

Ag NPs with sizes ranging form 5–6 nm confined into mesoporous silica SBA-15 (Ag-NPs/SBA-15) are successfully prepared by a facile and rapid glucose/glycol assisted one-step vacuum impregnation method. The as-prepared Ag-NPs/SBA-15 catalyst shows very good activity and selectivity for hydrogenation of chloronitrobenzenes to the corresponding chloroanilines by H2 compared with that of the SiO2 supported Ag catalysts. The robust catalytic performance of the as-prepared Ag-NPs/SBA-15 catalyst displays its potential application for the production of chloroanilines in the fine chemicals industry.

A novel graphene nanocomposite, functionalized by polymeric ionic liquids (PILs) and poly(sodium-p-styrenesulfonate) (PSS), was successfully prepared and exhibited excellent conductivity, favourable biocompatibility and good film-forming properties as an electrode material. TEM showed that the nanocomposite possessed an individual nanosheet-like structure. Owing to the surface modification of graphene, PSS/PILs–GP can not only be well dispersed in aqueous solution, but also possesses a strong negative charge. Due to electrostatic interactions, positively charged cholesterol oxidase (ChOx) can be immobilized onto the surface of PSS/PILs–GP to form the ChOx/PSS/PILs–GP/GC electrode material. UV-vis and FT-IR spectroscopy were used to monitor the assembly process of the nanocomposite. Due to the conductivity and biocompatibility of PSS/PILs–GP, the immobilized ChOx exhibited enhanced direct electron transfer (DET) at a glassy carbon (GC) electrode. Furthermore, the ChOx/PSS/PILs–GP/GC electrode displayed excellent catalytic performance with a wide linear range of 10.5 × 10−6 to 10.4 × 10−3 mol L−1, and a low detection limit of 3.5 μmol L−1 for the detection of cholesterol.

Cerasomes are a novel organic–inorganic hybrid material composed of spherical lipid bilayer vesicles with an internal aqueous compartment, which are similar to liposomes formed from phospholipids, with an inorganic silicate framework covering the vesicular surface. In this research, an anionic cerasome formed from N,N-dihexadecyl-N′-[(3-triethoxysilyl)propyl]urea was successfully prepared, and the cerasomes were characterized by scanning electron microscopy (SEM), behaving as a spherical-like structure. An electrochemical platform was constructed using a combination of the cerasomes and cholesterol oxidase (ChOx) on a glassy carbon electrode. Ultraviolet-visible (UV-vis) spectroscopy was used to monitor the assembly process and the electrochemical impedance spectroscopy (EIS) results demonstrated that ChOx had been successfully immobilized. The obtained enzyme-modified electrode exhibited both the effective direct electron transfer between the enzyme and electrode surface and the excellent electrochemical catalytic activity towards cholesterol with a wide linear range from 5.0 × 10−6 to 3.0 × 10−3 mol L−1 and a low detection limit 1.7 × 10−6 mol L−1 (S/N 3). The excellent catalytic performance of the modified electrode is attributed to the good biocompatibility of the cerasomes, which can provide a soft and morphologically stable interface for enzymatic immobilization, allowing the enzyme to retain its catalytic activity, along with their specific affinity (Km 0.139 mmol L−1) for water-insoluble cholesterol. The results indicate that cerasomes are useful as a platform for electrochemical sensing of cholesterol and have the potential to immobilize enzymes for bioelectrochemical applications.

4-Aminophenyl disulfide (APDS) forms on the surface of silver nanoparticles due to chemical adsorption and disulfide bond breakage. This leads to the formation of new silver chemical bonds to result in the new compound NH2-C6H6-S-Ag. This novel material produces enhanced Raman spectra under weak laser light irradiation. When irradiated a plasma-assisted catalytic coupling reaction of NH2-C6H6-S-Ag occurs leading to the formation of 4,4-dimercaptoazobenzene (DMAB). Raman spectroscopy was used to monitor this reaction process, showing clear spectral changes associated with each step after addition of Ag nanoparticles onto the APDS powder. This method clearly shows the mechanism of the plasma-assisted catalytic reaction and may also be useful for spectral imaging purposes.

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.

The rational design of active photoanodes for photoelectrochemical (PEC) water splitting is crucial for future applications in sustainable energy conversion. A combination of catalysts with photoelectrodes is generally required to improve surface kinetics and suppress surface recombination. In this study, we present an iridium complex (Ir-PO3H2) modified WO3 photoanode (WO3+Ir-PO3H2) for PEC water oxidation. When the Ir-based molecular catalyst (Ir-PO3H2) is anchored to a WO3 electrode, the photoanode shows a significant improvement both in photocurrent and faradaic efficiency compared to bare WO3. Under simulated sunlight illumination (AM 1.5G, 100 m Wcm−2) with an applied bias of 1.23 V vs. RHE, the photoanode exhibits a photocurrent of 1.16 mA cm−2 in acidic conditions, which is double that of bare WO3. The faradaic efficiency is promoted from 56% to 95%. Kinetic studies reveal that Ir-PO3H2 exhibits a different interfacial charge transfer mechanism on the WO3 photoanode for PEC water oxidation compared to iridium oxide (IrOx). Ir-PO3H2, as a water oxidation catalyst, can accelerate the surface charge transfer through rapid surface kinetics.

The vibrational spectra have been investigated for revealing the comprehensive structure of diferrocenyl-oligothienylene-vinylene complex, stimulated by the excellent experimental reports [group of Casado J. Am. Chem. Soc. 2012, 134, 12, 5675]. The IR and Raman spectra were simulated. It is found that the change of charge distribution and bond length are associated with the variation in the frequencies of specific vibration in infrared spectra for the neutral and radical oxidation states. The theoretical simulation of charge difference density indicate that charge transfer mechanism for neutral and dication states are significant different. The results can offer hints for the rational design of novel and interesting oligomer semiconductor.

Catalytic Janus nanosheets were synthesized by using an anion-exchange reaction between heteropolyacids (HPAs) and the modified ionic-liquid (IL) moieties of Janus nanosheets. Their morphology and surface properties were characterized by using SEM, energy-dispersive spectroscopy (EDS), FTIR spectroscopy, and X-ray photoelectron spectroscopy (XPS) studies. Because of their inherent Janus structure, the nanosheets exhibited good amphipathic character with ILs and oil to form a stable ILs-in-oil emulsion. Therefore, these Janus nanosheets can be used as both emulsifiers and catalysts to perform emulsive desulfurization. During this process, sulfur-containing compounds at the interface could be easily oxidized and efficiently removed from a model oil. Application of this Janus emulsion brings an efficient, useful, and green procedure to the desulfurization process. Compared with the desulfurization catalyzed by using HPAs in a conventional two-phase system, the sulfur removal of dibenzothiophene (DBT) achieved in a Janus emulsion system was improved from 68 to 97 % within 1.5 h. Moreover, this emulsion system could be demulsified easily by simple centrifugation to recover both the nanosheets and the ILs. Owing to the good structural stability of the Janus nanosheets, the sulfur removal efficiency of DBT could still reach 99.9 % after the catalytic nanosheets had been recycled at least six times.

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.

The intermolecular interaction between fluorenone (FN) and silver surfaces was investigated experimentally and theoretically. The structural, electronic and optical properties of the FN-Ag complex indicate that the carbonyl group O atom in FN molecules is the adsorbed position site to attach the silver substrate through the weak bond O…Ag. The analysis of vibrational modes and Raman activity of the largely enhanced Raman peaks using two FN-Ag4-x (x = l, s) complex models reveals that only the a1 vibrational modes with C 2v symmetry are selectively enhanced, from the point view of the change of dipole moment and polarizability induced by the interaction between FN and Ag4 substrate. Furthermore, the direct visualized evidence of the surface-enhanced Raman scattering (SERS) chemical enhancement mechanism for the FN-Ag complex is presented. The results reveal that only the intermolecular charge transfer with π-π transition characterization between FN and an Ag4 cluster facilitates the resonance Raman process and is directly responsible for chemical enhancement of Raman scattering of the FN-Ag complex.