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Homogeneous photocatalysis has considerably contributed to green applications such as energy production and environmental decontamination. Currently, researchers mainly focus on the search for sustainable processes that can generate valuable chemical compounds with high selectivity and aid in the complete mineralization of hazardous compounds. Although homogeneous photocatalysts exhibit superior performance, their recovery after the reaction is difficult. The 3Rs process, i.e., recovery, recycling and reuse of photocatalysts respectively, is critical to make a photocatalytic process eco-friendly. Heterogenization of homogeneous photocatalysts is considered as an effective method to not only realize the recycling of homogeneous photocatalysts, but also enhance the overall photocatalytic activity. Conventional methods have employed synthetic materials for the heterogenization of homogeneous photocatalysts. Nevertheless, scientists have discovered that natural polymer sources can be alternatives due to their excellent chemical, mechanical, and electrical properties for applications under harsh reaction conditions. In this review, we have summarized state-of-the-art techniques employed for the heterogenization of homogeneous photocatalysts using various supporting materials in terms of design and preparation. First, we have organized these strategies into different categories, such as microporous encapsulation, dye-sensitized semiconductors, metal–organic framework (MOF) construction, carbon material fixation, synthetic polymer attachment and natural origin supports. To provide readers with deeper insights into this field, we have presented some fundamentals of homogeneous photocatalysis with respect to environmental applications and its heterogeneous strategies. Furthermore, we have discussed the performance of heterogeneous photocatalysts prepared from these methods, including photocatalytic performance, product selectivity and reusability. Finally, we have concluded with different aspects on the current challenges and new aspects in emerging technologies.

For the global energy demand and climate change challenges, seeking renewable, sustainable energy sources is of great significance. Photoelectrochemical (PEC) water splitting is one of the promising technologies for converting intermittent solar energy into storable hydrogen energy, to tackle these issues. As the core component in a PEC system, photoelectrodes have been modified by various strategies including nanostructuring, facet-engineering, elemental doping, and heterostructured engineering. Apart from these techniques, numerous effective post-synthetic treatments have also been used to facilely and powerfully boost the physicochemical properties of photoelectrodes, for the enhancement of their PEC performance. Among them, a number of post-treatments can selectively influence photoelectrode surface and subsurface areas, altering surface states that play crucial roles in the hydrogen/oxygen evolution reaction. In virtue of such post-treatments, we summarize recently reported post-synthetic treatments for enhanced PEC applications. Post-treatment methods are classified into three sections: chemical treatments, electrochemical and irradiation-based treatments, and post-annealing treatments. In the end, a summary and outlook section regarding the utilization of post-treatments for PEC applications have been provided. This review can provide inspiration for further studies about post-treatments, not only in the PEC water splitting field, but also in other aspects, such as electrolysis.

Treatment of multidrug-resistant (MDR) bacterial infections increasingly relies on last-line antibiotics, such as polymyxins, with the urgent need for discovery of new antimicrobials. Nanotechnology-based antimicrobials have gained significant importance to prevent the catastrophic emergence of MDR over the past decade. In this study, phytantriol-based nanoparticles, named cubosomes, were prepared and examined in vitro by minimum inhibitory concentration (MIC) and time-kill assays against Gram-negative bacteria: Acinetobacter baumannii, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Phytantriol-based cubosomes were highly bactericidal against polymyxin-resistant, lipopolysaccharide (LPS)-deficient A. baumannii strains. Small-angle neutron scattering (SANS) was employed to understand the structural changes in biomimetic membranes that replicate the composition of these LPS-deficient strains upon treatment with cubosomes. Additionally, to further understand the membrane-cubosome interface, neutron reflectivity (NR) was used to investigate the interaction of cubosomes with model bacterial membranes on a solid support. These results reveal that cubosomes might be a new strategy for combating LPS-deficient Gram-negative pathogens.

Hybrid organic–inorganic halide perovskites have been extensively studied due to their remarkable optical and electronic features, such as high absorption coefficient, long exciton diffusion length, excellent carrier transport and low exciton binding energy, as well as a facile solution process for the fabrication of organic–inorganic halide perovskites. High-efficiency solar cells with methylammonium lead halide perovskites have been successfully achieved within just a few years. The high-quality perovskite films have made a significant impact on the fabrication of efficient and stable hybrid perovskite solar cells. Morphology engineering has been recognized as an effective way to obtain highly crystalline and pinhole-free perovskite films with optimized grain sizes. Here, we summarize several methodologies of morphology engineering, consisting of additive engineering, self-assembled monolayers (SAMs), solvent engineering, solvent annealing, thermal engineering, compositional engineering and humidity engineering. The highly crystallized perovskite layers prepared by using these techniques show a uniform surface morphology, resulting in enhanced photovoltaic efficiency and long-term stability of hybrid perovskite solar cells.

The composite of MoS2 and hollow carbon sphere (MoS2@HCS) is prepared via a glucose-assisted one pot synthesis. The composite consists of hierarchical spheres with a diameter of 0.5–4 μm and these hollow spheres are decorated with a number of curled and interlaced MoS2 nanosheets. After the composite is subject to the lithium intercalation, the MoS2 is converted from 2H to 1T phase. In this current work, the activities of 1T-MoS2@HCS toward photocatalytic hydrogen evolution and the reduction of I3− in dye-sensitized solar cells (DSCs) are systemically investigated. When evaluated as the photocatalyst for hydrogen evolution, the amount of evolved hydrogen over 1T-MoS2@HCS can reach 143 μmol in 2 h, being 3.6 times higher than as-synthesized 2H-MoS2@HCS. Additionally, the 1T-MoS2@HCS can be employed as the counter electrode (CE) material in DSCs. The DSCs based on 1T-MoS2@HCS CE possesses the power conversion efficiency of 8.94%, being higher than that with 2H-MoS2@HCS CE (8.16%) and comparable to that with Pt CE (8.87%). Our study demonstrates that 1T-MoS2@HCS has a great potential as an inexpensive alternative to Pt catalysts.

In this study, we demonstrate the formation of azo compounds on a composite of silver nanoparticles and graphene oxides (Ag@G) through a plasmon-assisted coupling reaction between different amine compounds. According to the time-dependent SERS experiments, 4-aminothiophenol (4ATP) molecules on Ag@G can be associated with external reactants such as 4-nitroaniline to form azo compounds when aided by the plasmons. Furthermore, the rate of the coupling reaction is dependent on the wavelength and the power of the excitation laser. It is noteworthy that the coupling reaction can only occur between two compounds containing amino groups in the presence of Ag nanoparticles. On the other hand, the NN double bond in the azo compound can be dissociated in a NaBH4 solution after 532 nm laser irradiation. The reduction of the azo compound results in the recovery of 4ATP molecules on Ag@G. Finally, we demonstrate that the plasmon-assisted coupling reaction allows for the immobilization of amine-terminated DNAs on 4ATP modified Ag@G. This DNA modified Ag@G can serve as the SERS substrate to sensitively detect its complementary DNA.

The Co 9 S 8 nanoparticles are homogeneously deposited on the conductive backbone of 3D graphene (3DG) by using a glucose-assisted hydrothermal method. The activation process for the composite of Co 9 S 8 and 3DG involving the consecutive cyclic voltammetry scanning in a 1 M KOH solution increases surface roughness of the composite electrode. As a result, the increase in the active surface area of the activated composite electrode leads to significant enhancement of electrode performance. Because the combination of the Co 9 S 8 nanoparticles and conductive 3DG generates a profound effect on the electrode, the activated composite electrode shows a high specific capacitance of 1721 F g −1 and great cycling stability at a relatively high current density of 16 A g −1 . Furthermore an asymmetric supercapacitor device assembled from the composite of Co 9 S 8 and 3DG and reduced graphene oxide hydrogel is tested to evaluate the capacitive performance of the composite electrode in a full-cell configuration. The fabricated device is capable of functioning with an output voltage of 1.8 V and delivering a maximum energy density of 31.6 Wh kg −1 at a power density of 910 W kg −1 . More importantly, the device exhibits great long-term stability with 86% capacitance retention after 6000 charge/discharge cycles.

Bi-functional peptides were designed to have binding abilities for both silica nanoparticles and miRNAs. Non-covalent self-assembly of peptides on large pore mesoporous silica nanoparticles provides a delivery system that shows a high binding capacity for nucleic acids, strong transfection efficiency of miRNA and attractive down-regulation of protein expression.

Lyotropic liquid crystalline nanoparticles (cubosomes) have the potential to act as amphiphilic scaffolds for the presentation of lipids and subsequent application in, for example, bioseparations and therapeutic delivery. In this work we have formulated lyotropic liquid crystalline systems based on the synthetic amphiphile 1,2,3-trihydroxy-3,7,11,15-tetramethylhexadecane (phytantriol) and containing the lipid dipalmitoyl phosphatidylserine (DPPS). We have prepared a range of DPPS-containing phytantriol cubosome formulations and characterized them using Small Angle X-ray Scattering and Cryo-transmission electron microscopy. These techniques show that increased DPPS content induces marked changes in lyotropic liquid crystalline phase behaviour, characterized by changes in crystallographic dimensions and increases in vesicle content. Furthermore, in vitro cell culture studies indicate that these changes correlate with lipid/surfactant cellular uptake and cytotoxicity. A model cell membrane based on a surface supported phospholipid bilayer was used to gain insights into cubosome–bilayer interactions using Quartz Crystal Microgravimetry. The data show that mass uptake at the supported bilayer increased with DPPS content. We propose that the cytotoxicity of the DPPS-containing dispersions results from changes in lipid/surfactant phase behaviour and the preferential attachment and fusion of vesicles at the cell membrane.

The field of organic solar cells (OSCs) has developed rapidly over the last two decades, and polymer solar cells with power conversion efficiencies of 13.1% have been reported. The understanding of the photophysical mechanisms in photovoltaic devices plays a significant role in determining the optoelectronic properties of high-performance OSCs. This review gives a fundamental description of the photophysical mechanisms in OSCs, with the main emphasis on the exciton transfer and charge-transfer mechanisms. In addition, it highlights the capabilities of various experimental techniques for the characterization of energy transfer and charge transport, as well as their roles in dictating the architecture of photovoltaic devices.

A novel surface-enhanced Raman scattering (SERS) sensing system which operates by the self-assembly of Ag nanoparticles (AgNPs) onto the nanocomposite of AgNPs and graphene oxide (AgNP-GO) in the presence of two complementary DNAs has been developed. In this system, AgNP-GO serves as a SERS-active substrate. The AgNPs with the modification of non-fluorescent 4-mercaptobenzoic acid (4-MBA) act as highly efficient Raman probes for DNA hybridization. When probe DNAs on AgNP-GO are complementary to target DNAs on AgNPs functionalized with 4-MBA, the DNA hybridization occurring directs the self-assembly of AgNPs onto AgNP-GO, leading to the creation of SERS hot spots. Due to the fact that partial 4-MBA molecules are located in the region of the hot spots, their SERS signals are greatly enhanced, indicating successful DNA hybridization. It is noteworthy that the size of AgNPs contributes significantly to the enhancement of SERS activity. The detection limit of the target DNAs at the pM level can be achieved through the self-assembly of large sized AgNPs onto AgNP-GO. More importantly, the AgNP-AgNP-GO system shows reproducible SERS signals in proportion to the logarithm of the target DNA concentrations spanning from 10(-6) to 10(-12) M and the excellent capability for multiplex DNA detection.

In this work we have formulated Annexin V (ANX) decorated phosphatidylserine containing phytantriol (PSPhy) cubosomes to act as probes for the enhanced detection of apoptotic membranes in both model and in vitro cell systems. Small angle X-ray scattering (SAXS) and cryogenic-transmission electron microscopy (Cryo-TEM) indicated that ANX-containing PSPhy (ANX-PSPhy) cubosomes retain the Pn3m cubic symmetry and cubic phase nanoparticle characteristics of PSPhy cubosomes. The interaction of ANX-PSPhy cubosomes with apoptotic model and cellular membranes was also investigated using both quartz crystal microbalance with dissipation and confocal microscopy which confirmed that ANX-PSPhy cubosomes can selectively bind to apoptotic cells and model membranes. Neutron reflectometry has also been used to show strong binding of ANX-PSPhy cubosomes to a model apoptotic membrane, and in addition reveals changes in both the bilayer structure and in the internal structure of the cubosome in a region adjacent to the membrane as a result of material exchange. This material exchange between cubosome and apoptotic model bilayer was further demonstrated using Cryo-TEM. We have demonstrated that lipid bound protein, in this case Annexin V, can be used to target cubosome systems to biological surfaces in vitro.

Biosurfactants are surface active biomolecules that are produced by a variety of different micro-organisms. The current environmental requirements for more biosustainable, biocompatible and biodegradable surfactant based products make the study of biosurfactants an important area of research. Understanding their fundamental physico-chemical properties and how these relate to their biological roles are key to their wider exploitation. This review focuses on studies of the fundamental adsorption and self-assembly properties of two glycolipids, rhamnolipids and sophorolipids, a lipopeptide, surfactin, and a protein, hydrophobin, and their mixtures with other amphiphiles and surfactants, using neutron reflectivity and small angle neutron scattering. © 2012 The Royal Society of Chemistry.

We demonstrate that single wall carbon nanotubes (SWCNTs) can be coated by a layer of silica through the reaction between chlorosilane and acid-treated SWCNTs. The presence of carboxylic acid groups in the SWCNTs provides the active sites where chlorosilane can be anchored to form the silica coating. Silica nanotubes with diameters ranging from 5 to 23 nm were synthesized after the calcination of silica coated SWCNTs at 900 degrees C in air. It was found that the presence of SWCNT templates and carboxylic acid groups on the SWCNTs' surface is essential to the formation of silica nanotubes. Furthermore, the dependence of the inner diameters of the silica nanotubes on the diameters of bundled or isolated SWCNTs was observed. This novel technique can be applied to the synthesis of other oxide nanotubes if a precursor such as TiCl(4) or ZrCl(4) is used.

We report the structure and Young's modulus of switchable films formed by peptide self-assembly at the air–water interface. Peptide surfactant AM1 forms an interfacial film that can be switched, reversibly, from a high- to low-elasticity state, with rapid loss of emulsion and foam stability. Using neutron reflectometry, we find that the AM1 film comprises a thin (approx. 15 Å) layer of ordered peptide in both states, confirming that it is possible to drastically alter the mechanical properties of an interfacial ensemble without significantly altering its concentration or macromolecular organization. We also report the first experimentally determined Young's modulus of a peptide film self-assembled at the air–water interface ( E =80 MPa for AM1, switching to E E and the macroscopic stability of peptide-containing foam. Finally, we report studies of a designed peptide surfactant, Lac21E, which we find forms a stronger switchable film than AM1 ( E =335 MPa switching to E