Hydrothermal synthesis, structural elucidation and electrochemical properties of three nickel and cobalt based phosphonates as anode materials for lithium ion batteries

Structural Design and Energy and Environmental Applications of Hydrogen-Bonded Organic Frameworks: A Systematic Review

Hydrogen-bonded organic frameworks (HOFs) are emerging porous materials that show high structural flexibility, mild synthetic conditions, good solution processability, easy healing and regeneration, and good recyclability. Although these properties give them many potential multifunctional applications, their frameworks are unstable due to the presence of only weak and reversible hydrogen bonds. In this work, the development history and synthesis methods of HOFs are reviewed, and categorize their structural design concepts and strategies to improve their stability. More importantly, due to the significant potential of the latest HOF-related research for addressing energy and environmental issues, this work discusses the latest advances in the methods of energy storage and conversion, energy substance generation and isolation, environmental detection and isolation, degradation and transformation, and biological applications. Furthermore, a discussion of the coupling orientation of HOF in the cross-cutting fields of energy and environment is presented for the first time. Finally, current challenges, opportunities, and strategies for the development of HOFs to advance their energy and environmental applications are discussed.

Hydrophobic POM Electrocatalyst Achieves Low Voltage "Charge" in Zn-Air Battery Coupled with Bisphenol A Degradation

Zn-air batteriesare a perspective power source for grid-storage. But, after they are discharged at1.1 to 1.2 V, large overpotential is required for their charging (usually 2.5 V). This is due to a sluggish oxygen evolution reaction (OER). Incorporating organic pollutants into the cathode electrolyte is a feasible strategy for lowering the required charging potential. In the discharge process, the related oxygen reduction reaction, hydrophobic electrocatalysts are more popular than hydrophilic ones. Here, a hydrophobic bifunctional polyoxometalate electrocatalyst is synthesized by precise structural design. It shows excellent activities in both bisphenol A degradation and oxygen reduction reactions. In bisphenol A containing electrolyte, to achieve 100 mA ⋅ cm^-2 , its potential is only 1.32 V, which is 0.34 V lower than oxygen evolution reaction. In the oxygen reduction reaction, this electrocatalyst follows the four-electron mechanism. In both bisphenol A degradation and oxygen reduction reactions, it shows excellent stability. With this electrocatalyst as cathode material and bisphenol A containing KOH as electrolyte, a Zn-air battery was assembled. When "charged" at 85 mA ⋅ cm^-2 , it only requires 1.98 V. Peak power density of this Zn-air battery reaches 120.5 mW ⋅ cm^-2 . More importantly, in the "charge" process, bisphenol A is degraded, which achieves energy saving and pollutant removal simultaneously in one Zn-air battery.

Nanoporous Metal Phosphonate Hybrid Materials as a Novel Platform for Emerging Applications: A Critical Review

Nanoporous metal phosphonates are propelling the rapid development of emerging energy storage, catalysis, environmental intervention, and biology, the performances of which touch many fundamental aspects of portable electronics, convenient transportation, and sustainable energy conversion systems. Recent years have witnessed tremendous research breakthroughs in these fields in terms of the fascinating pore properties, the structural periodicity, and versatile skeletons of porous metal phosphonates. This review presents recent milestones of porous metal phosphonate research, from the diversified synthesis strategies for controllable pore structures, to several important applications including adsorption and separation, energy conversion and storage, heterogeneous catalysis, membrane engineering, and biomaterials. Highlights of porous structure design for metal phosphonates are described throughout the review and the current challenges and perspectives for future research in this field are discussed at the end. The aim is to provide some guidance for the rational preparation of porous metal phosphonate materials and promote further applications to meet the urgent demands in emerging applications.

Ionothermal synthesis of octahedral lanthanoid coordination networks exhibiting slow magnetization relaxation and efficient photoluminescence

An ionothermal reaction of lanthanoid salts with tetraethyl-p-xylenediphosphonate (tepxdp) in ionic liquids, such as choline chloride and malonic acid, resulted in the formation of three novel lanthanoid-organic coordination networks with the formula [Ln(H2pxdp)1.5]n {Ln = Tb (1), Dy (2) and Ho(3) and H4pxdp = p-xylenediphosphonic acid}. The structures, photoluminescence and magnetic properties of the three compounds were investigated in detail. Single crystal X-ray diffraction analysis revealed that the three compounds are isostructural and the Ln3+ ions show an unusual six-coordinate environment with the {LnO6} octahedron. In these compounds, each {PO3C} tetrahedron is corner-shared with two {LnO6} octahedra and each {LnO6} octahedron is corner-shared with six {PO3C} tetrahedra, thus forming an inorganic layer in the crystallographic ab plane. The inorganic layers are further connected by a phenyl group, leading to a three-dimensional framework. Compound 1 exhibits the strong and characteristic emission of TbIII with an impressive quantum yield of 46.2%. Detailed magnetic analysis demonstrated that compound 2 displays a slow magnetic relaxation of magnetization with multiple relaxation mechanisms. The anisotropic energy barrier and the pre-exponential factor τ0 are 51.2 K and 3.9 × 10-7 s, respectively, in the presence of a direct-current field of 500 Oe. This work demonstrates a successful strategy to isolate octahedrally coordinated lanthanoid complexes through ionothermal synthesis to exhibit the single-ion-magnet-like behaviour and photoluminescence properties.

Using Diaper Waste to Prepare Magnetic Catalyst for the Synthesis of Glycerol Carbonate

Diaper waste was calcined above 400°C after impregnated in the solution of nickel nitrate. The as-prepared diaper waste-derived materials were used as magnetic catalysts for the synthesis of glycerol carbonate (GC). Structure and catalytic ability investigations on the catalysts calcined at different temperatures indicated that calcination temperature was an important factor affecting the property of catalysts. It was found that the catalyst obtained at the calcination temperature of 700°C (named DW-Ni-700) showed the best performance. When DW-Ni-700 was used in the synthesis of GC, GC yield reached 93.2%, and the magnetic property of DW-Ni-700 facilitated the catalyst separation process. Meanwhile, DW-Ni-700 showed high reusability in the reaction. After four times reuse of DW-Ni-700, GC yield decreased less than 4%.

Highly efficient Co3O4/CeO2 heterostructure as anode for lithium-ion batteries

Co₃O₄ has been extensively studied as an anode material for lithium-ion batteries (LIBs) because of its high theoretical capacity. However, during the charging-discharging processes, the issues of large volume change and low electric conductivity arise, which significantly limit the practical applications of Co₃O₄. To solve these issues, a Co₃O₄/CeO₂ heterostructure derived from metal-organic frameworks (MOFs) was designed and synthesized through one-step microwave synthesis. Benefiting from the mesoporous structure and presence of hetero-components, Co₃O₄/CeO₂ having the molar ratio of Co/Ce = 5:1 (denoted as 5Co₃O₄/CeO₂) exhibits high reversible capacity and excellent cycling stability when used as an anode material for LIBs. Specifically, compared to a single-phase Co₃O₄ anode, which shows a capacity of 538.6 mAh/g after 100 cycles, 5Co₃O₄/CeO₂ exhibits a higher capacity (1131.2 mAh/g at 100 mA/g). This study provides a novel strategy for using rare earth components to modify electrode materials.

NiMOF-derived oxygen vacancy rich NiO with excellent capacitance and ORR/OER activities as a cathode material for Zn-based hybrid batteries

An Ni-Zn battery is a distinguished member in the family of closed Zn-based batteries due to its ideal power density and voltage. However, when it is employed as a power supply for electric vehicles, its defects in terms of specific capacitance and energy density become obvious. Herein, to resolve this problem, a hybrid battery system was created through a combination of Ni-Zn and Zn-air batteries at the cell level. In a hybrid battery system, oxygen vacancy rich NiO with S,N co-modified mesoporous carbon as a matrix was used as the cathode material. This cathode material showed a high specific capacitance of 202.1 mA h g-1 at 1.0 A g-1. When the current density reduces to 20 A g-1, this value decreases to 130.2 mA h g-1, which implies that 64.4% of specific capacitance was retained. It also exhibits excellent OER and ORR activities. For the hybrid battery system, when the discharge process was carried out at 1 mA cm-2, there were two voltage plateaus at 1.72 and 1.12 V, which originated from Ni-Zn and Zn-air, respectively. In this case, its specific capacitance and energy density reaches 800.3 mA h g-1 and 961 W h kg-1, respectively. The hybrid battery also possesses perfect stability during multi-cycle charge-discharge tests. The construction of this hybrid battery system develops a new road to prepare a power supply device with high performance.

Synthesis, structure and photocatalytic properties of coordination polymers based on pyrazole carboxylic acid ligands

The photocatalytic activities of two novel different 2-D coordination polymers constructed from 5-hydroxy-1H-pyrazole-3-carboxylic acid ligand have been explored.