This research focuses on synthesizing a novel bimetallic metal-organic framework with a distinctive structure with distorted octahedral chains of CoO and CdO, linked by benzene tricarboxylic acid (BTC). Electrochemical testing revealed that bimetallic MOF/NF begins water oxidation at an onset potential of 1.62 V versus RHE, demonstrating high activity with a lower overpotential.

Abstract

In the realm of renewable energy technologies, the development of efficient and durable electrocatalysts is paramount, especially for applications like electrochemical water splitting. This research focuses on synthesizing a novel bimetallic metal-organic framework (BMMOF11) using earth-abundant elements, cobalt (Co) and cadmium (Cd). BMMOF11 showcases a distinctive structure with distorted octahedral chains of CoO and CdO, linked by benzene tricarboxylic acid (BTC). Our study primarily investigates the electrocatalytic efficiency of BMMOF11, particularly in water oxidation reactions. For practical analysis, BMMOF11 was anchored onto nickel foam, forming BMMOF11/NF, to evaluate its electrocatalytic properties. Electrochemical testing revealed that BMMOF11/NF begins water oxidation at an onset potential of 1.62 V versus RHE, demonstrating high activity with a lower overpotential of 0.4 V to achieve a current density of 10 mA/cm². Moreover, BMMOF11/NF maintained stable water splitting performance, sustaining a current density of approximately 70 mA/cm² under a voltage of 1.9 V relative to RHE. These findings indicate that BMMOF11/NF is a promising candidate for large-scale electrochemical water splitting, offering a blend of high activity and stability.

Drawing inspiration from hierarchical structures allowing for the transport and exchange of substances in the biological world, a three-dimensional ordered layered porous nitrogen-doped carbon-coated magnetic cobalt catalyst was successfully constructed and achieved outstanding OER performance. The existence of biomimetic grade pore structure can effectively reduce the mass transfer resistance, improve the material exchange efficiency, and accelerate the reaction kinetics.

Abstract

Metal-organic frameworks (MOFs) and their derivatives have been extensively employed in Oxygen Evolution Reaction (OER) catalysts due to their significantly larger specific surface areas, distinct metal centers, and well-organized porous structures. However, the microporous structure of MOFs and their derivatives presents mass transfer resistance, limiting their further development. Drawing inspiration from hierarchical structures allowing for the transport and exchange of substances in the biological world, we designed and fabricated biomimetic layered porous structures within ZIF-67 and its derivatives. Based on this, we achieved a three-dimensional ordered layered porous nitrogen-doped carbon-coated magnetic cobalt catalyst (3DOLP Co@NDC) with a biomimetic pore structure. It is found that the 3DOLP Co@NDC (352 mV @10 mA cm⁻¹) was better than Co@NDC (391 mV @10 mA cm⁻¹). The introduction of a three-dimensional ordered layered porous structure is conducive to increasing the specific surface area of the material, increasing the electrochemical active area, and improving the catalytic performance of the material. The introduction of a three-dimensional ordered layered porous structure would help to build a bionic grade pore structure. The existence of biomimetic grade pore structure can effectively reduce the mass transfer resistance, improve the material exchange efficiency, and accelerate the reaction kinetics.

Structural, thermal, and optical properties reveal that amorphous assembling is easily attained in a series of fluoranthene-fused [3.3.3]propellanes with a rigid 3D skeleton bearing n-butoxy or longer alkoxy groups. Drop-cast films can be obtained despite the high D _3h molecular symmetry and high ratios of π-core atoms to peripheral rotatable ones.

Abstract

Solid-state assembling modes are as crucial as the chemical structures of single molecules for real applications. In this work, solid-state structures and phase-transition temperatures are investigated for a series of fluoranthene-fused [3.3.3]propellanes consisting of a rigid three-dimensional (3D) π-core and varying lengths of alkoxy groups. Compounds in this series with n-butoxy or longer alkoxy groups take an amorphous state at room temperature. In these molecules, rotatable biaryl-type bonds are not incorporated and high D _3h molecular symmetry is retained. Therefore, π-fused [3.3.3]propellanes present a unique platform for amorphous molecular materials with low ratios of flexible alkoxy atoms to rigid π-core ones.

Due to the almost unlimited resource and acceptable performance, Sodium-ion batteries (SIBs) have been regarded as a promising alternatives for lithium-ion batteries for grid-scale energy storage. As the key material of SIBs, hard carbon (HC) plays a decisive role in determining the batteries’ performance. Nevertheless, the micro-structure of HCs is quite complex and the random organization of turbostratically stacked graphene layers, closed pores, and defects makes the structure-performance relationship insufficiently revealed. On the other hand, the impending large-scale deployment of SIBs leads to producing HCs with low-cost and abundant precursors actively pursued. In this work, the recent progress of preparing HCs from different precursors including biomass, polymers, and fossil fuels is summarized with close attention to the influences of precursors on the structural evolution of HCs. After a brief introduction of the structural features of HCs, the recent understanding of the structure-performance relationship of HCs for sodium storage is summarized. Then, the main focus is concentrated on the progress of producing HCs from distinct precursors. After that, the pros and cons of HCs derived from different precursors are comprehensively compared to conclude the selection rules of precursors. Finally, the further directions of HCs are deeply discussed to end this review.

With the demand to develop outstanding-performance energetic materials, 1-(dinitromethyl)-4,4',5,5'-tetranitro-1H,1'H-2,2'-biimidazole (DNM-TNBI) emerged as a great contender (D: 9102 m·s-1; P: 37.6 GPa). However, the relatively poor thermal stability (Td: 142 ℃) limits its practical application. In this study, DNM-TNBI as a host molecule to synthesize two new energetic open-framework materials by effectively coordinated with different cations. Their supramolecular structures were investigated and indicated that [DNM-TNBI2-][2NH4+] and [DNM-TNBI2-][2K+] can be classified as a new energetic hydrogen-bonded ammonium framework (EHAF) and an energetic metal organic framework (EMOF). Meanwhile, their thermal stabilities are higher than that of DNM-TNBI and have satisfactory detonation performance ([DNM-TNBI2-][2NH4+], D: 8050 m·s-1, P: 26.4 GPa; [DNM-TNBI2-][2K+], D: 8301 m·s-1, P: 30.8 GPa).

Using a non-labile Co (III) metal template and click reaction followed by de-metalation, synthesis of [2], linear [3], and radial [4] catenane has been achieved. Synthesized templated linear [2] catenane has an additional metal binding site for the synthesis of higher-order catenane through post-functionalization.

Abstract

Design and synthesis of higher order catenane are unexpectedly complex and involve precise cooperation among the precursors overcoming competing and opposing interactions. We achieved synthesis of [2], linear [3], radial [4] in a one-pot reaction by consecutive ring closing through click reactions. This synthesis gave three isolable products due to two, four, and six-click reactions between suitable coupling partners. Yields of the isolate templated-catenane decrease from lower to higher-ordered catenane (40 %, 12 %, and 4 %), probably due to the bite angle as well as the flexibility of the reacting partners. Removal of templating cobalt(III) ion leads to the formation of fully organic [2], linear [3], and radial [4]catenane. These synthesized catenanes were purified by column chromatography and characterized by ¹H-NMR, ¹³C-NMR, and ESI-MS spectroscopy. The synthesized catenanes have free binding sites suitable for post-functionalization and may be used for the synthesis of higher-ordered catenane.

Palladium serves as a multi-functional catalyst which is controllable by tuning reaction conditions. This work demonstrated the utilization of a palladium catalyst for the synthesis of phenanthrenols by cascade palladium-catalyzed Suzuki/Heck reaction between chalcone and 2-bromophenylboronic acid, followed by Michael addition. The sequential reaction could be controlled by reactivity of the palladium catalyst in different solvents and concentrations of reagents. This protocol could be applied to a broad range of substrates to give products in low to good yields.

Electrochemical sensors offer promising prospects for real-time pollutant monitoring. In this study, copper oxide-dispersed graphitic carbon nanofibers (CuO-CNFs) grown via chemical vapour deposition were employed as a robust platform for detecting a variety of environmental pollutants. This array-based sensor adeptly identifies three different classes of analytes, i.e., antibiotics (chloramphenicol (CP) and tylosin tartrate (TT)), heavy metals (cadmium (Cd) and lead (Pb)), and pesticides (quinalphos (QP) and imidacloprid (IP)). The CuO-CNF-modified GCE array rapidly discerns (<15 sec) a broad linear range: 1-20 ppm for CP, 1-13.33 ppm for TT, 0.66-11.66 ppm for Cd, 20-33.33 ppm for Pb, 1.6-11.6 ppm for QP, and 5-25 ppm for IP, boasting quantification limits of 1.0, 1.0, 0.66, 20.0, 1.6, and 5.0 ppm for CP, TT, Cd, Pb, QP, and IP, respectively. Notably, this sensor achieves simultaneous identification of mixed analytes, including CP and TT, Cd and Pb, and QP and IP, within real tap water. The electrochemical sensor exhibits robustness; heightened sensitivity, selectivity, and stability;  swift response; and impressive reproducibility in detecting CP, TT, Cd, Pb, QP, and IP within aqueous samples. Consequently, this array-based electrochemical sensor has emerged as a rapid and simultaneous detection tool for diverse pollutant residues in surface and groundwater samples.

In this work, we conducted a comparative analysis of the metal ion sensing capabilities of two pyridine-end oligo p-phenylenevinylene compounds featuring different alkyl substituents (-C4H9 and -C16H33) within a micelle medium. Our findings revealed a correlation between the positioning of the probe molecules within the micelle and the length of the alkyl chains, impacting their self-assembly tendencies and optical characteristics. The compound with shorter alkyl chains demonstrated a superior affinity towards Hg2+ ions, whereas exposure to the compound with longer alkyl substituent resulted in a color-changing response with both Cu2+and Hg2+ ions. Intriguingly, the sensitivity towards Hg2+ ions heightened with increasing alkyl chain length. This trend persisted in non-polar solvents like THF. The capacity to modulate sensing efficacy solely by adjusting the length of the alkyl chains represents a relatively uncommon occurrence in the existing literature. This discovery suggests promising prospects for engineering sensory devices equipped with adaptable sensitivity.

New members of swedenborgite mineral structure were prepared and characterized. The material, InBaZn_2.75Cu_0.25GaO₇, exhibits visible light assisted photocatalysis for the aerobic oxidation of styrenes. The substitution of transition elements in these oxides gives rise to new colored materials, which may be attractive candidates as new inorganic pigments.

Abstract

A new compound, InBaZn₃GaO₇, with swedenborgite structure along with transition metal (TM) substituted variants have also been prepared. The structure contains layers of tetrahedral ions (Zn²⁺/Ga³⁺) connected by octahedrally coordinated In³⁺ ion forming the three-dimensional structure with voids where the Ba²⁺ ions occupy. The TM substituted compounds form with new colors. The origin of the color was understood based on the ligand-field transitions. The near IR reflectivity studies indicate that the Ni – substituted compounds exhibit good near – IR reflectivity behavior, making them possible candidates for ‘cool pigments’. The temperature dependent dielectric studies indicate that the InBaZn₃GaO₇ compound undergoes a phase transition at ~360 °C. The compounds are active towards second harmonic generation (SHG). Magnetic studies show the compounds, InBaZn₂CoFeO₇ and InBaZn₂CuFeO₇ to be anti-ferromagnetic in nature. The copper containing compounds were found to be good catalysts, under visible light, for the oxidation of aromatic alkenes. The many properties observed in the swedenborgite structure-based compounds suggests that the mineral structure offers a fertile ground to investigate newer compounds and properties.