Situ preparation of SiO2 on graphene-assisted anti-oxidation for resol phenolic resin

Surfactant-assisted molecular-level tunning of phenol-formaldehyde-based hard carbon microspheres for high-performance sodium-ion batteries

The phenol-formaldehyde (PF) resin is an economical precursor for spherical hard carbon (HC) anodes for sodium-ion batteries (SIBs). However, achieving precise molecular-level control of PF-based HC microspheres, particularly for optimizing ion transport microstructure, is challenging. Here, a sodium linoleate (SL)-assisted strategy is proposed to enable molecular-level engineering of PF-based HC microspheres. PF microspheres are synthesized through the polymerization of 3-aminophenol and formaldehyde, initially forming oxazine rings and then undergoing ring-opening polymerization to create a macromolecular network. SL functions as both a surfactant to control microsphere size and a catalyst to enhance ring-opening polymerization and increase polymerization of PF resin. These modifications lead to reduced microsphere diameter, increased interlayer spacing, enhanced graphitization, and significantly improved electron and ion transfer. The synthesized HC microspheres exhibit a remarkable reversible capacity of 337 mAh/g, maintaining 96.9 mAh/g even at a high current density of 5.0 A/g. Furthermore, the full cell demonstrates a high capacity of 150 mAh/g, an energy density of 125.3 Wh kg-1, an impressive initial coulombic efficiency (ICE) of 930.3% at 1 A/g, and remarkable long-term stability over 3000 cycles. This study highlights the potential of surfactant-assisted molecular-level engineering in customizing HC microspheres for advanced SIBs.

New Ln-MOFs based on mixed organic ligands: synthesis, structure and efficient luminescence sensing of the Hg2+ ions in aqueous solutions

In view of Hg²⁺ ion sensing by luminescence, a series of new, phenanthroline-decorated 3D lanthanide metal organic frameworks (Ln-MOFs) valorising an original combination of four different lanthanides and two organic ligands, i.e. thiobis(4-methylene-benzoic acid) (H₂tmba) and 1,10-phenanthroline (phen), have been successfully synthesized, namely {[Ln₄(tmba)₆(phen)₄]·m(H₂O)(phen)}_n [Ln = Ce, m = 3 (1); Pr, m = 1 (2); Eu, m = 3 (3); and Tb, m = 3 (4)]. Compounds 1-4 were characterised by single-crystal X-ray diffraction, elemental and thermogravimetric analyses, and powder X-ray diffraction. The luminescence properties of complexes 3 and 4 were thoroughly investigated. It is herein proved that compound 3 sensitively and selectively acts as an excellent luminescent probe for the detection of Hg²⁺ ions in waters, with a detection limit of 1.00 μM. As additional assets, 3 displays superb stability over a wide pH range (3-12) of the aqueous media, as well as convenient recycling after completion of the detection experiments. The rationale for the observed luminescence quenching effect of mercury might be a strong interaction arising between Hg²⁺ ions and the carboxylate oxygen atoms of the tmba^2- ligand. The results open new perspectives for applications in environmental remediation.

Conversion of phenolic mixture to refractory resins: A resourcezation strategy for phenolic distillation residues

A new resourcezation way has been proposed to address the treatment challenges of the light phenolic distillation residue (LPDR) from the coal-based phenolic distillation residue. Herein, the LPDR, which was collected at 20 kPa and 220 °C from the phenolic distillation residue, has been further used to synthesize the phenolic resin (named as RPF) for MgO-C refractories. It is found that the conversion efficiency of crude phenol mixture to RPF is 71.3%, which is lower than that of pure phenol. To increase the conversion efficiency and improve the properties of RPF, the crude phenolic mixture was blended with pure phenol for the synthesis. The optimal addition mass ratio of phenol in the crude phenol mixture (phenol/total phenolic compounds) is determined to be 0.8, where the obtained RPF could satisfy or even better than the national standard. Further addition of 10 wt% of urotropine (HMTA) as curing agent and 9 wt% of ferrocene (Fc) as modifier (named as MRPF) are found to significantly improve the graphitization of RPF. Under these conditions, the DTG at temperature of maximum mass lose rate (T_max) of MRPF was lower than that of commercial resin. The graphitization level was as high as 61.6% with the residual carbon rate up to 41.4%, which are higher than those of national standard. These findings provide insights for the resourcezation of the phenolic distillation residue.

A water-stable europium-MOF as a multifunctional luminescent sensor for some trivalent metal ions (Fe3+, Cr3+, Al3+), PO43− ions, and nitroaromatic explosives

Eu-MOF having a layered structure exhibits high sensitivity, selectivity, and recyclability towards sensing Fe³⁺, Cr³⁺, Al³⁺, and PO₄³⁻ ions and TNP.

A water-stable terbium-MOF sensor for the selective, sensitive, and recyclable detection of Al3+ and CO32− ions

A layered Tb-MOF structure exhibits high sensitivity, selectivity, and concurrently low limits of detection in relation to Al³⁺ and CO₃²⁻ ions.