A Cu/MnOx Composite with Copper-Doping-Induced Oxygen Vacancies as a Cathode for Aqueous Zinc-Ion Batteries.

Aqueous zinc-ion batteries are anticipated to be the next generation of important energy storage devices to replace lithium-ion batteries due to the ongoing use of lithium resources and the safety hazards associated with organic electrolytes in lithium-ion batteries. Manganese-based compounds, including MnOx materials, have prominent places among the many zinc-ion battery cathode materials. Additionally, Cu doping can cause the creation of an oxygen vacancy, which increases the material's internal electric field and enhances cycle stability. MnOx also has great cyclic stability and promotes ion transport. At a current density of 0.2 A g-1, the Cu/MnOx nanocomposite obtained a high specific capacitance of 304.4 mAh g-1. In addition, Cu/MnOx nanocomposites showed A high specific capacity of 198.9 mAh g-1 after 1000 cycles at a current density of 0.5 A g-1. Therefore, Cu/MnOx nanocomposites are expected to be a strong contender for the next generation of zinc-ion battery cathode materials in high energy density storage systems.

A photothermal assisted zinc-air battery cathode based on pyroelectric and photocatalytic effect.

Zinc-air battery as one of the new generations of battery system, its theoretical specific energy is as high as 1086 Wh kg-1, specific capacity up to 820 mAh/g, and zinc has the advantages of environmental friendliness, resource abundance, low cost and good safety, so it has attracted much attention. However, due to its slow reaction kinetic process, zinc-air battery will produce a large charging overpotential usually up to 2 V, it is far beyond the theoretical voltage of 1.65 V, so reducing the overpotential of zinc-air batteries is extremely necessary, and the most common way to solve this problem is to use excellent catalyst cathode to improve the oxygen reduction and oxygen evolution kinetics of zinc-air batteries. So we developed a new photothermal assisted zinc-air battery system with Hollow carbon nanosphere@poly (vinylidene fluoride-trifluoroethylene-chlorofluoroethylene)@CdS(HCN@PVTC@CdS) photocathode, the pyroelectric and photocatalysis effect can effectively promote the reaction kinetics and reduce the reaction overpotential. With the pyroelectric and photocatalysis synergistic effect, the zinc-air has displayed a high discharge potential of 1.33 V and a low charging potential of 1.5 V with good cycle stability. This multi-assist technology with built-in electric and light fields paves the way for the development of high-performance zinc-air batteries and other energy storage systems.

Research progress of anaerobic ammonium oxidation (Anammox) process based on integrated fixed-film activated sludge (IFAS).

The integrated fixed-film activated sludge (IFAS) process is considered one of the cutting-edge solutions to the traditional wastewater treatment challenges, allowing suspended sludge and attached biofilm to grow in the same system. In addition, the coupling of IFAS with anaerobic ammonium oxidation (Anammox) can further improve the efficiency of biological denitrification. This paper summarises the research progress of IFAS coupled with the anammox process, including partial nitrification anammox, simultaneous partial nitrification anammox and denitrification, and partial denitrification anammox technologies, and describes the factors that limit the development of related processes. The effects of dissolved oxygen, influent carbon source, sludge retention time, temperature, microbial community, and nitrite-oxidising bacteria inhibition methods on the anammox of IFAS are presented. At the same time, this paper gives an outlook on future research focus and engineering practice direction of the process.

Hydraulic characterization and start-up of a novel circulating flow bio-carriers.

High-quality biofilm carriers are crucial for the formation of biofilm, but problems such as slow biofilm growth on the carrier surface have been troubling a large number of researchers. The addition of a carrier changes the flow state in the reactor, which in turn affects the microbial attachment and the quantity of microorganisms. Also, aerobic microorganisms need to use dissolved oxygen in the water to remove water pollutants. In this paper, a novel recirculating flow carrier with a hollow cylinder structure is proposed, with a certain number of hollow inverted circular plates placed at equal distances inside. In this paper, the hydraulic residence time, aeration volume, and the spacing of the inflow plates of the recirculating flow biofilm carrier, which are three important factors affecting the hydraulic characteristics of the reactor, are first investigated. At the same time, it was compared with the common combined carrier to find the optimal operating conditions for the hydraulic characteristics. Secondly, a reactor start-up study was carried out to confirm that the new recirculating flow biofilm carrier could accelerate the biofilm growth by changing the hydraulic characteristics. The results showed that under the same conditions, the hydraulic properties of the reactor were better with the addition of the recirculating flow carrier, with an effective volume ratio of 98% and a significant reduction in short flows and dead zones. The stabilized removal of COD, NH3-N, and TN in the reactor with the addition of the recirculating flow carrier reached about 94%, 99%, and 91% respectively, at the beginning of the 15th day, which effectively proved the feasibility of the recirculating flow carrier.

High pressure Raman study of LiClO4.

Lithium perchlorate (LiClO4), as one of the new high-energy oxidizers, is chosen for high pressure Raman research to gain a better understanding of the structure and stability, which is very important for the performance of an explosive. Raman spectra of LiClO4 crystal have been measured from ambient to 25.07 GPa with diamond anvil cells (DACs) at room temperature to investigate the structural stability of this system. Raman vibrational modes of LiClO4 crystal at ambient pressure were resolved comprehensively on the basis of our experimental and calculated results. Upon increase of pressure on LiClO4 crystal sample to 1.96 GPa, it was found that the LiClO4 crystal exhibited a pressure-induced first-order phase transformation behavior. The occurrence of a second phase transformation of LiClO4 crystal induced by pressure was observed at about 5.09 GPa. Both phase transformations were demonstrated based on the detailed spectroscopic analysis of the variations in the number of lattice modes, splitting of Raman bands and frequency jumps of the Raman vibrational modes of LiClO4 crystal.

Pressure-Engineered Ti3C2Tx MXene with Enhanced Conductivity and Accelerated Reaction Kinetics of Lithium Storage.

We studied the structure-function relationship of compressed Ti3C2Tx MXene using high-pressure in situ synchrotron radiation, impedance spectroscopy, Hall effect measurements, and first-principles calculations. With increasing pressure, the conductivity of Ti3C2Tx MXene increases along with its continued lattice shrinkage. A pressure range of 0.4-2.2 GPa exhibits a sharp decrease in resistance, which decreases by more than one order of magnitude from 3.3 × 104 to 1.4 × 103 Ω. A pressure range of 2.2-6.6 GPa exhibits a steady resistance with a slight decrease of 0.2%. As the pressure drops to atmospheric conditions, the resistance increases slightly to 4.2 × 103 Ω. This is accompanied by a transformation of the semiconductor into metal. An irreversible increase in conductivity is observed owing to an increase in the electron concentration and a decrease in the grain-boundary potential barrier. Furthermore, abundant Ti3C2Tx undergoing prepressure treatments (0.4, 2.0, and 4.0 GPa) was first prepared using a double-anvil hydraulic press. The recycled samples retain an accordion-like layered structure with slight lattice shrinkage while the voids between the sheets contract considerably, increasing the density. Correspondingly, electrochemical results show a pressure threshold of 2.0 GPa based on the rapid quenching from the hydraulic press. This weakens the electric polarization in redox reactions and increases the ionic transport rate for the formation of a Ti3C2Tx anode owing to pressure improving the conductivity and interlaminar densification. Our study shows a new, simple, and universal way to regulate various MXenes and also promotes the application of MXene-based materials in energy storage and related fields.

Co,N-co-doped graphene sheet as a sulfur host for high-performance lithium-sulfur batteries.

To improve the performance of lithium-sulfur (Li-S) batteries, herein, based on the idea of designing a material that can adsorb polysulfides and improve the reaction kinetics, a Co,N-co-doped graphene composite (Co-N-G) was prepared. According to the characterization of Co-N-G, there was a homogeneous and dispersed distribution of N and Co active sites embedded in the Co-N-G sample. The 2D sheet-like microstructure and Co, N with a strong binding energy provided significant physical and chemical adsorption functions, which are conducive to the bonding S and suppression of LiPSs. Moreover, the dispersed Co and N as catalysts promoted the reaction kinetics in Li-S batteries via the reutilization of LiPSs and reduced the electrochemical resistance. Thus, the discharge specific capacity in the first cycle for the Co-N-G/S battery reached 1255.7 mA h g-1 at 0.2C. After 100 cycles, it could still reach 803.0 mA h g-1, with a retention rate of about 64%. This phenomenon proves that this type of Co-N-G composite with Co and N catalysts plays an effective role in improving the performance of batteries and can be further studied in Li-S batteries.

Raman spectroscopy study of acetonitrile at low temperature.

We report the low-temperature studies of liquid CH3CN by Raman spectral measurements at ambient pressure with decreasing the temperature from 20 to -196 °C. Detailed internal modes especially the lattice modes analysis revealed that the structural phase transitions of acetonitrile from liquid to solid phase ß and solid phase ß to solid phase α were occurring at -50 and -60 °C, respectively. Further, the Fermi resonance parameters between the fundamental ν2 and combination (ν3 + ν4) of CH3CN at different temperatures were calculated based on the Bertran's equations. It is found that the Fermi resonance parameters as a function of temperature become discontinued at -50 and -60 °C, which coincides with discontinuities observed in the Raman shifts of CH3CN at -50 and -60 °C. The results suggest that the Fermi resonance parameters could be used as an indicator to assess the structural phase transition for CH3CN under low temperature.

4-Isopropyl-amino-3-nitro-benzonitrile.

In the title compound, C(10)H(11)N(3)O(2), the nitro group is essentially coplanar with the aromatic ring [dihedral angle = 3.4 (3)°] and forms an intra-molecular N-H⋯O hydrogen bond with the amine group. In the crystal, weak aromatic C-H⋯O and C-H⋯N hydrogen bonds link the mol-ecules. Weak aromatic ring π-π inter-actions [minimum ring centroid-centroid separation = 3.9841 (16) Å] are also present.

3-Nitro-4-(propyl-amino)-benzonitrile.

In the title compound, C(10)H(11)N(3)O(2), the nitro group is essentially coplanar with the aromatic ring [dihedral angle = 1.3 (3)°] and forms an intra-molecular amine-nitro N-H⋯O hydrogen bond. In the crystal, weak inter-molecular aromatic C-H⋯O(nitro) hydrogen bonds link the mol-ecules. Weak aromatic ring π-π inter-actions [minimum ring centroid separation = 3.7744 (13) Å] are also present.

2-(4-Hy-droxy-phen-oxy)propanoic acid.

In the title compound, C(9)H(10)O(4), the carboxyl group is oriented at a dihedral angle of 84.6 (3)° with respect to the benzene ring. In the crystal, mol-ecules are linked via O-H⋯O hydrogen bonds.

Ethyl 1-[(4-acetyl-2-methoxy-phen-oxy)meth-yl]cyclo-propane-1-carboxyl-ate.

In the title compound, C(16)H(20)O(5), the dihedral angle between the planar rings, viz. benzene and cyclo-propane, is 52.1 (2)°. Mol-ecules are connected in the crystal via weak inter-molecular C-H⋯O hydrogen bonds, forming chains in the [001] direction.

1-(4-Isopropyl-phen-yl)-5-(4-methoxy-phen-yl)pyrazolidin-3-one.

In the mol-ecule of the title compound, C(19)H(22)N(2)O(2), the pyrazolidinone ring has an envelope conformation, with the C atom attached to the 4-methoxy-phenyl ring displaced by 0.354 (3) Šfrom the plane of the other ring atoms. The 4-iso-propyl-phenyl ring is oriented with respect to the 4-meth-oxy-phenyl ring at a dihedral angle of 88.94 (3)°. Intra-molecular C-H⋯N hydrogen bonds result in the formation of two planar five-membered rings, which are oriented with respect to the adjacent 4-isopropyl-phenyl and 4-meth-oxy-phenyl rings at dihedral angles of 4.05 (3) and 0.50 (3)°, respectively. In the crystal structure, inter-molecular N-H⋯O hydrogen bonds link the mol-ecules into centrosymmetric dimers.