Kai-Ming Zhang

The photo-catalytic performance for the reduction of CO₂ to CO can be significantly enhanced by covalently anchoring metal Ni on the COF-Tp-Azo.

Two open-framework zinc phosphates [C₃N₂H₁₂][Zn(HPO₄)₂] (1) and [C₆N₄H₂₂]_0.5[Zn(HPO₄)₂] (2) were synthesized via hydrothermal reaction and characterized by powder X-ray diffraction, thermogravimetric analysis and scanning electron microscopy. Both compounds have a similar crystal structure and macroscopic morphology. However, the difference in equilibrium cations, in which the propylene diamine is for 1 and the triethylenetetramine is for 2, results in a significant distinction in the dense hydrogen grid. The diprotonated propylene diamine molecule in 1 is more favorable for forming a hydrogen-bond network in three dimensions than in 2, in which the twisted triethylenetetramine forms a hydrogen bond grid with the inorganic framework only in two dimensions owing to its large steric effect. This distinction further leads to a disparity in the proton conductivity of both compounds. The proton conductivity of 1 can reach 1.00 × 10⁻³ S cm⁻¹ under ambient conditions (303 K and 75% RH) and then increase to 1.11 × 10⁻² S cm⁻¹ at 333 K and 99% RH, which is the highest value among the open-framework metal phosphate proton conductors operated in the same conduction. In contrast, the proton conductivity of 2 is four orders of magnitude smaller than 1 at 303 K and 75% RH and two orders smaller than 1 at 333 K and 99% RH.

Herein we report the first example of the proton conductivity of an open-framework metal phosphate (NH ₃ (CH ₂ ) ₃ NH ₃ ) ₂ –[Fe ₄ (OH) ₃ (HPO ₄ ) ₂ (PO ₄ ) ₃ ]·4H ₂ O under aqua-ammonia vapor.

An investigation was performed into the structure recovery of highly concentrated water-in-oil emulsions (HCEs) under shear flow via studying their rheopexy. Experiments with the shear rate sweep in the up and down modes demonstrate that HCE has rheopexy. Restoration of the initial structure after cessation of shearing needs a period of time. The recovery time and ratio depend on the shear rate and the droplet size of the dispersed phase. A high shear rate results in a high probability of structure break of HCE. Thus, it is difficult to return to its initial structure. The structure of HCE that underwent shearing is closer to its original situation when the droplet size is small.

The inorganic–organic hybrid metal hydrogenophosphate with a formula of (C₂H₁₀N₂)[Mn₂(HPO₄)₃](H₂O) (1) shows layered crystal structure. The inorganic anion layer is built from Mn₃O₁₃ cluster units, and the interlayer spaces are filled by the charge-compensated ethylenediammonium dications together with the lattice water molecules. The thermogravimetry, variable-temperature powder X-ray diffraction, and the proton conductance under anhydrous and moisture environments were investigated for 1, disclosing that 1 shows high thermal stability and high proton transport nature, and the proton conductivity reaches to 1.64 × 10^–3 S·cm^–1 under 99%RH even at 293 K. The high proton conductivity is related to the formation of denser H-bond networks in the lattice.

An investigation was performed into the rheological properties and stability of emulsion explosive matrix with different surfactants. The surfactants were oligomers of the polyisobutylene succinic anhydride (PIBSA) based on different head group and relative low molecular weight sorbitan monooleate (Span 80). The viscosity, shear stress, and storage modulus of emulsion explosive matrix depend on the nature of surfactants. It was shown that the matrix formed by Span 80 has a lower viscosity, shear stress, and storage modulus, compared with the PIBSA-based surfactants, especially the blended surfactant of Span 80 and PIBSA-TEA. The result of the precipitation of ammonium nitrate (AN) and the change of storage modulus with time show that the strength of interfacial film formed by Span 80 is weak. This allows the crystal of AN to pass through the interfacial film more easily; thus, the stability of the matrix is decreased. However, the storage modulus in aging was approximately constant and the ratio of the precipitation of AN is the lowest when the matrix was stabilized by blended surfactant. It shows that the matrix formed by blended surfactant has a better stability than single surfactants. GRAPHICAL ABSTRACT

Powdery emulsion explosive (PEE), a new powdery industrial explosive with perfect properties, has been made using an emulsification–spray drying technique. PEE is composed of 91–92.5 wt% ammonium nitrate (AN), 4.5–6 wt% organic fuels, and 1.5–1.8 wt% water. Due to its microstructure as a water-in-oil (W/O) emulsion and low water content, it has excellent detonation performance, outstanding water resistance, reliable safety, and good application compared with other industrial explosives, such as ammonite, emulsion explosives, and ANFO.