Covalent grafting of molecular catalysts on CN H as robust, efficient and well-defined photocatalysts for solar fuel synthesis.

The covalent attachment of molecules to 2D materials is an emerging area as strong covalent chemistry offers new hybrid properties and greater mechanical stability compared with nanoparticles. A nickel bis-aminothiophenol catalyst was grafted onto a range of 2D carbon nitrides (CN H ) to form noble metal-free photocatalysts for H production. The hybrids produce H beyond 8 days with turnover numbers reaching 1360 based on nickel, a more than 3 fold higher durability than reported molecular catalyst-carbon nitride mixtures, and under longer wavelengths (>475 nm).

A Metal-Free Oxygenated Covalent Triazine 2-D Photocatalyst Works Effectively from the Ultraviolet to Near-Infrared Spectrum for Water Oxidation Apart from Water Reduction.

Solar-driven water splitting is highly desirable for hydrogen fuel production, particularly if water oxidation is effectively sustained in a complete cycle and/or by means of stable and efficient photocatalysts of main group elements, for example, carbon and nitrogen. Despite extensive success on H production on polymer photocatalysts, polymers have met with very limited success for the rate-determining step of the water splitting-water oxidation reaction due to the extremely slow "four-hole" chemistry. Here, the synthesized metal-free oxygenated covalent triazine (OCT) is remarkably active for oxygen production in a wide operation window from UV to visible and even to NIR (up to 800 nm), neatly matching the solar spectrum with an unprecedented external quantum efficiency (even 1% at 600 nm) apart from excellent activity for H production under full arc irradiation, a big step moving toward full solar spectrum water splitting.

Tunable Covalent Triazine-Based Frameworks (CTF-0) for Visible-Light-Driven Hydrogen and Oxygen Generation from Water Splitting.

Covalent triazine-based frameworks (CTFs), a group of semiconductive polymers, have been identified for photocatalytic water splitting recently. Their adjustable band gap and facile processing offer great potential for discovery and development. Here, we present a series of CTF-0 materials fabricated by two different approaches, a microwave-assisted synthesis and an ionothermal method, for water splitting driven by visible-light irradiation.

Hierarchical ZnO@Hybrid Carbon Core-Shell Nanowire Array on a Graphene Fiber Microelectrode for Ultrasensitive Detection of 2,4,6-Trinitrotoluene.

A hierarchical architecture composed of nitrogen (N)-rich carbon@graphitic carbon-coated ZnO nanowire arrays on a graphene fiber (ZnO@C/GF) was fabricated by direct growth of a ZnO@zeolitic imidazolate framework-8 (ZIF-8) core-shell nanowire array on a GF followed by annealing and used as a microelectrode for detection of 2,4,6-trinitrotoluene (TNT). In such a design, ZnO accumulated TNT through a strong nitroxide-zinc interaction and ZIF-8 served as the precursor of the N-rich carbon@graphitic carbon layer that seamlessly connected ZnO with the GF to improve the poor conductivity of ZnO, thus enhancing the sensitivity of the ZnO@C/GF microelectrode. The constructed hierarchical hybrid fiber microsensor exhibited a wide linear response to TNT in a concentration range of 0.

Ultra-small dispersed Cu O nanoparticles on graphene fibers for miniaturized electrochemical sensor applications.

A graphene microfiber (GF) modified with ultrafine Cu O nanoparticles (Cu ONPs/GF) has been fabricated by direct annealing of electrodeposited nano-sized copper-based metal organic frameworks (HKUST-1) and used as an electrode for nonenzymatic HO sensing. Benefiting from the unique microfiber architecture and synergetic effects, as well as strong coupling between components with many active sites and boosted electron transport, the Cu ONPs/GF electrode shows prominent sensitivity, selectivity and long-term operational stability for the detection of HO. Further work successfully applied this Cu ONPs/GF electrode to detection of HO in real samples such as milk and human serum.

A 3D-graphene fiber electrode embedded with nitrogen-rich-carbon-coated ZIF-67 for the ultrasensitive detection of adrenaline.

A novel nitrogen-rich-carbon-coated ZIF-67 embedded three-dimensional-graphene (ZIF-67/NC/3DG) fiber was fabricated via a facile one-pot electrodeposition self-assembly method, and used as a prominent electrode for the non-enzymatic detection of adrenaline (Ad). In this design, the prepared ZIF-67 adsorbs Ad through hydrogen bonding and electrostatic interaction, while polypyrrole functions as the precursor of the conductive NC that seamlessly connects ZIF-67 with the 3DG fiber electrode to ameliorate the poor conductivity of the ZIF-67 moiety and thus improve the sensitivity of the ZIF-67/NC/3DG fiber electrode for detecting Ad. The constructed fiber sensor shows a double linear response over the Ad concentration range of 0.

Earth-Abundant Molecular Z-Scheme Photoelectrochemical Cell for Overall Water-Splitting.

A push-pull organic dye and a cobaloxime catalyst were successfully cografted on NiO and CuGaO to form efficient molecular photocathodes for H production with >80% Faradaic efficiency. CuGaO is emerging as a more effective p-type semiconductor in photoelectrochemical cells and yields a photocathode with 4-fold higher photocurrent densities and 400 mV more positive onset photocurrent potential compared to the one based on NiO. Such an optimized CuGaO photocathode was combined with a TaON|CoO photoanode in a photoelectrochemical cell.

Insights into the mechanism and aging of a noble-metal free H-evolving dye-sensitized photocathode.

Dye-sensitized photo-electrochemical cells (DS-PECs) form an emerging technology for the large-scale storage of solar energy in the form of (solar) fuels because of the low cost and ease of processing of their constitutive photoelectrode materials. Preparing such molecular photocathodes requires a well-controlled co-immobilization of molecular dyes and catalysts onto transparent semiconducting materials. Here we used a series of surface analysis techniques to describe the molecular assembly of a push-pull organic dye and a cobalt diimine-dioxime catalyst co-grafted on a p-type NiO electrode substrate.

A protocol for quantifying hydrogen evolution by dye-sensitized molecular photocathodes and its implementation for evaluating a new covalent architecture based on an optimized dye-catalyst dyad.

A protocol that combines gas chromatography and a high-sensitivity micro Clark-type electrode is described to quantify hydrogen production across gas and solution phases for systems operating at very low currents such as dye-sensitized H-evolving photocathodes. Data indicate that a significant fraction of H remains in aqueous solution even after several hours of experiments. Using this protocol, re-evaluation of a dye-sensitized H-evolving photocathode based on a dye-catalyst dyad showed a reproducible 66% increase of the faradaic efficiency compared with previously reported headspace GC measurements [Kaeffer et al.

Time-Resolved IR Spectroscopy Reveals a Mechanism with TiO as a Reversible Electron Acceptor in a TiO-Re Catalyst System for CO Photoreduction.

Attaching the phosphonated molecular catalyst [ReBr(bpy)(CO)] to the wide-bandgap semiconductor TiO strongly enhances the rate of visible-light-driven reduction of CO to CO in dimethylformamide with triethanolamine (TEOA) as sacrificial electron donor. Herein, we show by transient mid-IR spectroscopy that the mechanism of catalyst photoreduction is initiated by ultrafast electron injection into TiO, followed by rapid (ps-ns) and sequential two-electron oxidation of TEOA that is coordinated to the Re center. The injected electrons can be stored in the conduction band of TiO on an ms-s time scale, and we propose that they lead to further reduction of the Re catalyst and completion of the catalytic cycle.

Electrocatalytic and Solar-Driven CO2 Reduction to CO with a Molecular Manganese Catalyst Immobilized on Mesoporous TiO2.

Electrocatalytic CO2 reduction to CO was achieved with a novel Mn complex, fac-[MnBr(4,4'-bis(phosphonic acid)-2,2'-bipyridine)(CO)3 ] (MnP), immobilized on a mesoporous TiO2 electrode. A benchmark turnover number of 112±17 was attained with these TiO2 |MnP electrodes after 2 h electrolysis. Post-catalysis IR spectroscopy demonstrated that the molecular structure of the MnP catalyst was retained.

Comparison of rhenium-porphyrin dyads for CO photoreduction: photocatalytic studies and charge separation dynamics studied by time-resolved IR spectroscopy.

We report a study of the photocatalytic reduction of CO to CO by zinc porphyrins covalently linked to [Re(2,2'-bipyridine)(CO)L] moieties with visible light of wavelength >520 nm. contains an amide CHNHC(O) link from porphyrin to bipyridine (Bpy), contains an additional methoxybenzamide within the bridge CHNHC(O)CH(OMe)NHC(O), while has a saturated bridge CHNHC(O)CH; each dyad is studied with either L = Br or 3-picoline. The syntheses, spectroscopic characterisation and cyclic voltammetry of and are described.

Heterogenised Molecular Catalysts for the Reduction of CO2 to Fuels.

CO(2) conversion provides a possible solution to curtail the growing CO(2) levels in our atmosphere and reduce dependence on fossil fuels. To this end, it is essential to develop efficient catalysts for the reduction of CO(2). The structure and activity of molecular CO(2) reduction catalysts can be tuned and they offer good selectivity with reasonable stability.

Heterogenised Molecular Catalysts for the Reduction of CO₂ to Fuels.

CO2 conversion provides a possible solution to curtail the growing CO2 levels in our atmosphere and reduce dependence on fossil fuels. To this end, it is essential to develop efficient catalysts for the reduction of CO2. The structure and activity of molecular CO2 reduction catalysts can be tuned and they offer good selectivity with reasonable stability.

Improving the photocatalytic reduction of CO2 to CO through immobilisation of a molecular Re catalyst on TiO2.

The photocatalytic activity of phosphonated Re complexes, [Re(2,2'-bipyridine-4,4'-bisphosphonic acid) (CO)3(L)] (ReP; L = 3-picoline or bromide) immobilised on TiO2 nanoparticles is reported. The heterogenised Re catalyst on the semiconductor, ReP-TiO2 hybrid, displays an improvement in CO2 reduction photocatalysis. A high turnover number (TON) of 48 molCO molRe(-1) is observed in DMF with the electron donor triethanolamine at λ>420 nm.

CO2 photoreduction with long-wavelength light: dyads and monomers of zinc porphyrin and rhenium bipyridine.

Photocatalytic CO(2) reduction has been studied for two dyads with porphyrin covalently attached to rhenium tricarbonyl bipyridine moieties, and on separate components consisting of [Re(CO)(3)(Picoline)Bpy](+) and either zinc porphyrin or zinc chlorin. TONs decrease in the order: zinc porphyrin + Re > long spacer dyad > zinc chlorin + Re > short spacer dyad.

Cholesterol and lipid phases influence the interactions between serotonin receptor agonists and lipid bilayers.

Solid state NMR techniques have been used to investigate the effect that two serotonin receptor 1a agonists (quipazine and LY-165,163) have on the phase behavior of, and interactions within, cholesterol/phosphocholine lipid bilayers. The presence of agonist, and particularly LY-165,163, appears to widen the phase transitions, an effect that is much more pronounced in the presence of cholesterol. It was found that both agonists locate close to the cholesterol, and their interactions with the lipids are modulated by the lipid phases.