A porous Ni–Fe oxide with improved crystallinity has been prepared as a highly efficient electrocatalytic water oxidation catalyst. It has a small overpotential, a low Tafel slope, and an outstanding stability. The remarkably improved electrocatalytic performance is due to the porous structure, high extent homogeneous iron incorporation, ameliorative crystallinity, and the low mass transfer resistance.

The development of new materials/structures for efficient electrocatalytic water oxidation, which is a key reaction in realizing artificial photosynthesis, is an ongoing challenge. Herein, a Co(OH)F material as a new electrocatalyst for the oxygen evolution reaction (OER) is reported. The as-prepared 3D Co(OH)F microspheres are built by 2D nanoflake building blocks, which are further woven by 1D nanorod foundations. Weaving and building the substructures (1D nanorods and 2D nanoflakes) provides high structural void porosity with sufficient interior space in the resulting 3D material. The hierarchical structure of this Co(OH)F material combines the merits of all material dimensions in heterogeneous catalysis. The anisotropic low-dimensional (1D and 2D) substructures possess the advantages of a high surface-to-volume ratio and fast charge transport. The interconnectivity of the nanorods is also beneficial for charge transport. The high-dimensional (3D) architecture results in sufficient active sites per the projected electrode surface area and is favorable for efficient mass diffusion during catalysis. A low overpotential of 313 mV is required to drive an OER current density of 10 mA cm on a simple glassy carbon (GC) working electrode in a 1.0 m KOH aqueous solution.

Anisotropic 2D layered material rhenium disulfide (ReS2 ) with high crystal quality and uniform monolayer thickness is synthesized by using tellurium-assisted epitaxial growth on mica substrate. Benefit from the lower eutectic temperature of rhenium-tellurium binary eutectic, ReS2 can grow from rhenium (melting point at 3180 °C) and sulfur precursors in the temperature range of 460-900 °C with high efficiency.

Stimulus-responsive gels have recently attracted widespread attention as new functional materials for potential applications in sensors, [1] actuators, [2] shape memories, [3] drug delivery devices, [4] and displays. [5] One of the promising properties that organogels based on low molecular mass organic gelators (LMOGs) can offer is their reversible sol-gel phase transition as a result of external stimuli. [6] As far as we know, redoxresponsive organogels from LMOGs, however, are limited. Shinkai and coworkers [7a] reported the first example of organogels of this kind, which contains a redox-active Cu I / Cu II center. Besides, they also synthesized a series of quater-, quinque-, and sexithiophene derivatives bearing two cholesteryl moieties at the a-position. It was found that a sol-gel phase transition can be implemented by addition of oxidizing and reducing reagents.[7b] Zhu and colleagues [7c] prepared an electro-active LMOG containing a tetrathiafulvalene (TTF) entity. The gel formation can be tuned by means of oxidation/ reduction of the TTF group chemically or electrochemically. Although these gel systems are redox responsive, their properties, such as mechanical strength, flexibility, and sensitivity to external stimulus, are far from those required for practical uses. Therefore, creating instant, reversible, redox-responsive, and mechanically flexible organogels still remains a challenge. As a remarkable organometallic compound, ferrocene (Fc) contains an oxidizable metal ion, Fe II , and is a nonpolar compound in the neutral state, and thereby it dissolves readily in hydrocarbon solvents. This property, however, can be easily reversed by simple oxidation of the central ion. Our interest in stimulus-responsive supramolecular gel systems led us to consider the compound as a neutral-cation redox pair that may be employed to tune the gelling ability of a gelator containing it. Actually, the same idea has been adopted by a number of groups for studies of switchable complexation and molecular aggregation in micelles and vesicles. [8] However, all compounds containing the apolar ferrocenyl or charged ferrocenium moiety reported so far do not result in gelation, as documented for a number of solvents. [8b,8c] Introduction of metal ions is a practical way of giving organogels some smart properties.[9] For example, Sijbesma and coworkers [9a] designed and prepared two chloroform gels with reported a palladium-based organometallic LMOG that is able to catalyze C-C bond formation even in the gel state. We report here four novel cholesterol-appended ferrocene derivatives ( Fig. 1a; see Supporting Information for preparation details), and present first evidence for the gelation ability of organometallic compounds of this kind, and particularly the unusual redox-, mechanical-, and ultrasonic-controllable sol-gel phase transition phenomena. These gelators contain one redox-active ferrocenyl moiety and one cholesteryl residue linked by different diamino units. This design was chosen on the basis of the analys...

No abstract

Sensitive and rapid identification of illicit drugs in a non-contact mode remains a challenge for years. Here we report three film-based fluorescent sensors showing unprecedented sensitivity, selectivity, and response speed to the existence of six widely abused illicit drugs, including methamphetamine (MAPA), ecstasy, magu, caffeine, phenobarbital (PB), and ketamine in vapor phase. Importantly, for these drugs, the sensing can be successfully performed after 5.0 × 105, 4.0 × 105, 2.0 × 105, 1.0 × 105, 4.0 × 104, and 2.0 × 102 times dilution of their saturated vapor with air at room temperature, respectively. Also, presence of odorous substances (toiletries, fruits, dirty clothes, etc.), water, and amido-bond-containing organic compounds (typical organic amines, legal drugs, and different amino acids) shows little effect upon the sensing. More importantly, discrimination and identification of them can be realized by using the sensors in an array way. Based upon the discoveries, a conceptual, two-sensor based detector is developed, and non-contact detection of the drugs is realized.

Co-Pi decorated TiO 2 @graphitic carbon nitrides (g-C 3 N 4 ) nanorod arrays (denoted as CCNRs) with different mass ratios of g-C 3 N 4 have been constructed on the FTO substrate through three processes, hydrothermal growth, chemical bath deposition and electrodeposition. Firstly, TiO 2 nanorod arrays were grown onto a FTO substrate by a hydrothermal method. Secondly, g-C 3 N 4 was coated onto the TiO 2 nanorod arrays by immersing the above substrate with TiO 2 nanorod arrays into a solution of urea and then heated at higher temperature. In this procedure, the amount of the g-C 3 N 4 on the TiO 2 nanorod arrays can be controlled by tuning the concentration of the urea solution. At last, Co-Pi were decorated on the surface of the TiO 2 @g-C 3 N 4 by electrodeposition. The as-prepared CCNRs were characterized by XRD, FESEM, TEM, XPS, UV-vis and FTIR, respectively, which illustrated that Co-Pi were successfully decorated on the hybrid TiO 2 @g-C 3 N 4 nanorod arrays.Photoelectrochemical (PEC) measurements have demonstrated that the prepared CCNRs serve as an efficient and stable photoanode for PEC seawater splitting. The photocurrent density reaches 1.6 mA/cm 2 under 100 mW/cm 2 (AM1.5G) light illumination at 1.23 V (RHE). More significantly, the CCNRs photoanode is quite stable during seawater splitting and the performance remain undiminished even after ten hours continuous illumination. Finally, a systematical photocatalytic mechanism of the Co-Pi decorated TiO 2 @g-C 3 N 4 was proposed and it can be considered as potential explanation of enhanced PEC performance. .7 eV 35 , has attracted more and more attentions for its inherent chemical and thermal stability 36, 37 . Unlike transitional metal oxides and sulfide semiconductor photocatalysts, g-C 3 N 4 behaves very stable performance in acid or alkaline electrolytes ascribing to strong covalent bonds between carbon and nitride atoms in its structure 38 . However, applications of pure g-C 3 N 4 are limited largely because of its low quantum efficiency and high electron-hole recombination rate 39 .Therefore, it lays a large space to explore and construct novel composite materials to remedy these deficiencies of pure g-C 3 N 4 .Herein, we combined TiO 2 and g-C 3 N 4 to fabricate TiO 2 @g-C 3 N 4 nanorod arrays 40 with different mass ratios of g-C 3 N 4 via hydrothermal growth and chemical bath deposition. Moreover, the composite nanorod arrays were decorated with Co-Pi particles 41-43 to offset the inadequacy of g-C 3 N 4 44 . To the best of our knowledge, this is the first report upon semiconductor nanorod arrays modified with tunable g-C 3 N 4 mass ratio. As reported, Co-Pi decorated TiO 2 @g-C 3 N 4 nanorod arrays (CCNRs) used for photoelectrode within PEC cells are still unexplored. More importantly, the results in this work have proved that the composited nanorod arrays as photoelectrodes exhibit very efficient and stable performances for PEC seawater splitting.

Hydrogen production from seawater and solar energy based on photoelectrochemical cells is extremely attractive due to earth-abundance of seawater and solar radiation. Herein, we report the successful fabrication of novel inorganic-organic 2D/2D WO3/g-C3N4 nanosheet arrays (WO3/g-C3N4 NSAs) grown on a FTO substrate via a facile hydrothermal growth and deposition-annealing process, and their application in natural seawater splitting. The results indicate that the WO3/g-C3N4 NSAs exhibit a photocurrent density of 0.73 mA cm(-2) at 1.23 V versus RHE under AM 1.5G (100 mW cm(-2)) illumination, which is 2-fold higher than that of WO3 NSAs. More importantly, the WO3/g-C3N4 NSA photoanode is quite stable during seawater splitting and the photocurrent density does not substantially decrease after continuous illumination for 3600 s. The remarkably enhanced performance originates primarily from the formation of the WO3/g-C3N4 heterojunction between WO3 and g-C3N4 nanosheets, which accelerates charge transfer and separation, and prolongs the lifetime of electrons as demonstrated by EIS and Mott-Schottky analyses. Finally, a possible mechanism for the improved performance was proposed and discussed.