A marine coating: Self-healing, stable release of Cu2+, anti-biofouling.

We developed a marine coating consisting of Cu-MOF-74, multi-walled carbon nanotube containing carboxyl groups (MWCNT-COOH) and self-healing polymers, which simultaneously possesses self-healing and anti-biofouling properties. Cu-MOF-74 can stably release Cu2+ by virtue of the coordination dissociative mechanism. Studies have proved that MWCNT can inhibit the growth of bacteria, so adding the MWCNT can help to reduce the amount of the copper ions and ensure the antibacterial effect of the coating. In addition, the cross-linked network and abundant -COOH provided by the polymers and MWCNT-COOH further prevent the loss of copper ions. Moreover, the coating we prepared has good performance of self-healing at room temperature or slightly heated because the polymers possess abundant non-covalent hydrogen bonds. Finally, the coating not only has superior antibacterial property, but also effectively prevents the adhesion of macrofouling organism. Therefore, the coating has a longer service life and its environmental friendliness has also been improved.

Self-Enhanced Antibacterial and Antifouling Behavior of Three-Dimensional Porous Cu2O Nanoparticles Functionalized by an Organic-Inorganic Hybrid Matrix.

Cu2O is currently an important protective material for domestic engineering and equipment used to exploit marine resources. Cu+ is considered to have more effective antibacterial and antifouling activities than Cu2+. However, disproportionation of Cu+ in the natural environment leads to its reduced bioavailability and weakened reactivity. Novel and functionalized Cu2O composites could enable efficient and environmentally friendly applications of Cu+. To this end, a series of three-dimensional porous Cu2O nanoparticles (3DNP-Cu2O) functionalized by organic (redox gel, R-Gel)-inorganic (reduced graphene oxide, rGO) hybrids─3DNP-Cu2O/rGOx@R-Gel─at room temperature by immobilization-reduction method was prepared and applied for protection against marine biofouling. 3DNP-Cu2O/rGO1.76@R-Gel includes rGO and R-Gel shape 3D porous Cu2O nanoparticles with diameters ∼177 nm and strong dispersion and antioxidant stability. Compared with commercial Cu2O (Cu2O-0), 3DNP-Cu2O/rGO1.76@R-Gel exhibited an ∼50% higher bactericidal rate, ∼96.22% higher water content, and ∼75% lower adhesion of mussels and barnacles. Moreover, 3DNP-Cu2O/rGOx@R-Gel maintains the same excellent, stable, and long-lasting bactericidal performance as Cu2O-0@R-Gel while reducing the average copper ion release concentration by ∼56 to 76%. This was also confirmed by X-ray diffraction, X-ray photoelectric spectroscopy (XPS), atomic absorption spectroscopy, and antifouling tests. In addition, XPS tests of rGO-Cu2+ and R-Gel-Cu2+, photocurrent tests of 3DNP-Cu2O/rGO1.76@R-Gel, and energy-dispersive spectrometry pictures of bacteria confirm that R-Gel and rGO act as electron donors and transfer substrates driving the reduction of Cu2+ (Cu2+ → Cu+) and the diffusion of Cu+. Thus, a self-growing antibacterial and antifouling system of 3DNP-Cu2O/rGO1.76@R-Gel was achieved. The mechanism of accelerated bacterial inactivation and resistance to mussel and barnacle adhesion by 3DNP-Cu2O/rGO1.76@R-Gel was interpreted. It is shown that rGO and R-Gel are important players in the antibacterial and antifouling system of 3DNP-Cu2O/rGO1.76@R-Gel.

Wood-Inspired Ultrafast High-Performance Adsorbents for CO2 Capture.

Under favorable regeneration conditions (120 °C, 100% CO2), ultrafast adsorption kinetics and excellent long-term cycle stability are still the biggest obstacles for amine-based solid CO2 adsorbents. Inspired by natural wood, a biochar with a highly ordered pore structure and excellent thermal conductivity was prepared and used as a carrier of organic amines to prepare ideal CO2 adsorbents. The results showed that the prepared adsorbent has a very high adsorption working capacity (4.23 mmol CO2·g-1), and its performance remains stable even after 30 adsorption-desorption cycles in the harsh desorption environment (120 °C, 100% CO2). Due to the existence of the hierarchical structure, the adsorbent exhibited ultra-fast adsorption kinetics, and the reaction rate constant is 37 times higher than that of traditional silica. This adsorbent also showed a very low regeneration heat of 1.64 MJ·kg-1 (CO2), which is especially important for the practical application. Therefore, these biochar-based adsorbents derived from natural wood make the CO2 capture process promising.

Water- and Acid-Sensitive Cu2O@Cu-MOF Nano Sustained-Release Capsules with Superior Antifouling Behaviors.

Marine biofouling is one of the technical bottlenecks restricting the development of the global marine economy. Among the commercial self-polishing antifouling coatings, cuprous oxide is an irreplaceable component because of its efficiency and broad-spectrum antibacterial activity. However, one of the biggest obstacles to achieving long-term antifouling is the "initial burst and final decay" of cuprous oxide in the coating. Here, we lock the copper ions by establishing an antifouling unit composed of Cu2O (core) and Cu-based metal-organic framework (Cu-MOF, shell). Cu-MOF is densely grown in situ on the periphery of Cu2O by acid proton etching. The shell structure of Cu-MOF can effectively improve the stability of the internal Cu2O and thus achieve the stable and slow release of copper ions. Furthermore, Cu2O@Cu-MOF nanocapsules can also achieve active defense by rapid and complete dissolution of Cu2O@Cu-MOF at local acidic microenvironment (pH ≤ 5) where the adhesion of fouling organisms occurs. Super-resolution fluorescence microscopy is used to explain the sterilization mechanism. Relying on the water- and acid-sensitive properties of Cu-MOF shell, the stable, controlled and efficient release of copper ions has been achieved for the Cu2O@Cu-MOF nanocapsules in the self-polishing antifouling coatings. Thus, these controlled-release nanocapsules make long-term antifouling promising.

Ultrafast Carbon Dioxide Sorption Kinetics Using Morphology-Controllable Lithium Zirconate.

It was reported that the main obstacle of Li2ZrO3 as high-temperature CO2 absorbents is the very slow CO2 sorption kinetics, which are ascribed to the gradual formation of compact zirconia and carbonate shells along with inner unreacted lithium zirconate cores; accordingly, the "sticky" Li+ and O2- ions have to travel a long distance through the solid shells by diffusion. We report here that three-dimensional interconnected nanoporous Li2ZrO3 exhibiting ultrafast kinetics is promising for CO2 sorption. Specifically, nanoporous Li2ZrO3 (LZ-NP) exhibited a rapid sorption rate of 10.28 wt %/min with an uptake of 27 wt % of CO2. Typically, the k1 values of LZ-NP (kinetic parameters extracted from sorption kinetics) were nearly 1 order of magnitude higher than the previously reported conventional Li2ZrO3 reaction systems. Its sorption capacity of 25 wt % within ∼4 min is 2 orders of magnitude faster than those obtained using spherical Li2ZrO3 powders. Furthermore, nanoporous Li2ZrO3 exhibited good stability over 60 absorption-desorption cycles, showing its potential for practical CO2 capture applications. CO2 adsorption isotherms for Li2ZrO3 absorbents were successfully modeled using a double-exponential equation at various CO2 partial pressures.

Hierarchically Structured Graphene Coupled Microporous Organic Polymers for Superior CO2 Capture.

Hierarchically porous materials containing interconnected macro-/meso-/micropores are promising candidates for energy storage, catalysis, and gas separation. Here, we present an effective approach for synthesizing three-dimensional (3D) sulfonated graphene coupled microporous organic polymers (SG-MOPs). The resulting SG-MOPs possess uniform macropores with an average size of ca. 350 nm, abundant mesopores, and micropores with an average size of ca. 0.6 nm. The SG-supported adsorbents exhibit a high nitrogen content (more than 38.1 wt %), high adsorption capacity (up to 3.37 mmol CO2 g-1), high CO2/N2 selectivity from 42 to 51, moderate heat of adsorption, as well as good stability because of the hierarchical porous structure and excellent thermal conductivity of the SG scaffold. Thus, these nitrogen-enriched adsorbents allow the overall CO2 capture process to be promising and sustainable.

Amine-tethered adsorbents based on three-dimensional macroporous silica for CO(2) capture from simulated flue gas and air.

New covalently tethered CO2 adsorbents are synthesized through the in situ polymerization of N-carboxyanhydride (NCA) of l-alanine from amine-functionalized three-dimensional (3D) interconnected macroporous silica (MPS). The interconnected macropores provide low-resistant pathways for the diffusion of CO2 molecules, while the abundant mesopores ensure the high pore volume. The adsorbents exhibit high molecular weight (of up to 13058 Da), high amine loading (more than 10.98 mmol N g(-1)), fast CO2 capture kinetics (t1/2 < 1 min), high adsorption capacity (of up to 3.86 mmol CO2 g(-1) in simulated flue gas and 2.65 mmol CO2 g(-1) in simulated ambient air under 1 atm of dry CO2), as well as good stability over 120 adsorption-desorption cycles, which allows the overall CO2 capture process to be promising and sustainable.

Di-bromido-bis-(2-methyl-1H-benzimidazole-κN (3))cadmium.

In the title compound, [CdBr2(C8H8N2)2], the Cd(II) atom has a distorted tetra-hedral coordination formed by the two imino N atoms of two 2-methyl-benzimidazole ligands and two terminal bromide ligands. The Cd(II) atom is slightly out of the benzimidazole planes by 0.320 (3) and 0.210 (3) Å. The dihedral angle between the benzimidazole planes is 71.6 (2)°. In the crystal, mol-ecules are linked by N-H⋯Br hydrogen bonds into puckered layers parallel to (001).

Three-dimensional conducting oxide nanoarchitectures: morphology-controllable synthesis, characterization, and applications in lithium-ion batteries.

We report the synthesis, characterization and applications in Li-ion batteries of a set of 3-dimensional (3-D) nanostructured conducting oxides including fluorinated tin oxide (FTO) and aluminum zinc oxide (AZO). The morphology of these 3-D conducting oxide nanoarchitectures can be directed towards either mono-dispersed hollow nanobead matrix or mono-dispersed sponge-like nanoporous matrix by controlling the surface charge of the templating polystyrene (PS) nanobeads, the steric hindrance and hydrolysis rates of the precursors, pH of the solvents etc. during the evaporative co-assembly of the PS beads. These 3-D nanostructured conducting oxide matrices possess high surface area (over 100 m(2) g(-1)) and accessible interconnected pores extending in all three spatial dimensions. By optimizing the temperature profile during calcination, we can obtain large area (of a few cm(2)) and crack-free nanoarchitectured films with thickness over 60 µm. As such, the sheet resistance of these nanoarchitectured films on FTO glass can reach below 20 Ω per square. The nanoarchitectured FTO electrodes were used as anodes in Li-ion batteries, and they showed an enhanced cycling performance and stability over pure SnO2.

5,6-Dimethyl-1H-benzimidazol-3-ium nitrate.

The title salt, C9H11N2 (+)·NO3 (-), features a planar cation (r.m.s. for 11 non-H atoms = 0.016 Å). In the crystal, N-H⋯O hydrogen bonds link nitrate and benzimidazole ions into a three-dimensional network.

Enhanced electron extraction from template-free 3D nanoparticulate transparent conducting oxide (TCO) electrodes for dye-sensitized solar cells.

The semiconducting metal oxide-based photoanodes in the most efficient dye-sensitized solar cells (DSSCs) desires a low doping level to promote charge separation, which, however, limits the subsequent electron extraction in the slow diffusion regime. These conflicts are mitigated in a new photoanode design that decouples the charge separation and extraction functions. A three-dimensional highly doped fluorinated SnO(2) (FTO) nanoparticulate film serves as conductive core for low-resistance and drift-assisted charge extraction while a thin, low-doped conformal TiO(2) shell maintains a large resistance to recombination (and therefore long charge lifetime). EIS reveals that the electron transit time is reduced by orders of magnitude, whereas the recombination resistance remains in the range of traditional nanoparticle TiO(2) photoelectrodes.

A novel hybridization indicator for the low-background detection of short DNA fragments based on an electrically neutral cobalt(II) complex.

An electrically neutral cobalt complex, Co(Eim)(4)(NCS)(2) (Eim=1-ethylimidazole, NCS=isothiocyanate) was synthesized and its interaction with double-stranded DNA (dsDNA) was comprehensively studied by electrochemical methods on a glassy carbon electrode (GCE). The experimental results revealed that the cobalt complex could interact with dsDNA via a specific groove-binding mode with an affinity constant of 3.6×10(5)M(-1). The surface-based studies showed that Co(Eim)(4)(NCS)(2) could electrochemically accumulate within the immobilized dsDNA layer rather than single-stranded DNA (ssDNA) layer. Based on this fact, the cobalt complex was utilized as an electrochemical hybridization indicator for the detection of oligonucleotides related to CaMV35S promoter gene. The results showed that the developed biosensor presented very low background interference due to the negligible affinity of the Co(Eim)(4)(NCS)(2) complex with ssDNA. The hybridization specificity experiments further indicated that the biosensor could well discriminate the complementary sequence from the base-mismatched and the non-complementary sequences. The complementary target sequence could be quantified over the range from 5.0×10(-9)M to 2.0×10(-6)M with a detection limit of 2.0×10(-10)M.

catena-Poly[[bis-(1-allyl-imidazole)zinc(II)]-µ-phthalato-κO:O].

The structure of the title compound, [Zn(C(8)H(4)O(4))(C(6)H(8)N(2))(2)](n), exhibits polymeric zigzag chains extended along the c axis. The Zn(II) ion is coordinated by two N [Zn-N = 2.008 (6) and 2.012 (6) Å] and two O [Zn-O = 1.959 (5) and 1.985 (5) Å] atoms in a distorted tetra-hedral geometry. Weak C-H⋯O inter-actions contribute to the crystal packing stability.

Tetra-kis(1-ethyl-1H-imidazole-κN)bis-(thio-cyanato-κN)cadmium(II).

The structure of the title compound, [Cd(NCS)(2)(C(5)H(8)N(2))(4)], consists of isolated mol-ecules of [Cd(NCS)(2)(Eim)(4)] (Eim = 1-ethyl-imidazole), which contain a compressed octa-hedral CdN(6) chromophore. The NCS(-) anions are trans and four N atoms from the 1-ethyl-imidazole ligands define the equatorial plane. The mean Cd-N(Eim) and Cd-N(NCS) distances are 2.334 (4) and 2.379 (5) Å, respectively. Weak C-H⋯N inter-actions contribute to the crystal packing stability.

Spectroscopic, viscositic and electrochemical studies of DNA interaction with a novel mixed-ligand complex of nickel (II) that incorporates 1-methylimidazole and thiocyanate groups.

A novel mixed-ligand nickel(II) complex that contains 1-methylimidazole and thiocyanate, Ni(NCS)(2)(Mim)(4) (Mim=1-methylimidazole), was synthesized and its structure was determined by X-ray crystallography, IR spectrum and elemental analysis, etc. Its DNA-binding properties were studied by electronic absorption spectral, viscositive and electrochemical measurements. The absorption spectral and viscositive results suggest that the nickel(II) complex binds to DNA via partial intercalation. The addition of DNA results in the decrease of the peak current of the nickel(II) complex proved their interaction. The slight differences of peak profiles and electrochemical parameters between free and DNA-bound Ni(NCS)(2)(Mim)(4) showed the formation of an electrochemical inactive complex between Ni(NCS)(2)(Mim)(4) and DNA. The binding site and binding constant of the complex to DNA were determined by electrochemical titration method.