Qi Feng

Nanosheet–polymer composite membranes are widely used in water treatment, such as ultrafiltration (UF) and reverse osmosis (RO) membranes, due to reduced polymer voids and ease of large-scale fabrication. Herein, we report polyvinylidene fluoride (PVDF) composite membranes (~ 10 μm thickness) incorporating carbon nitride–reduced graphene oxide (CN-rGO) nanosheets, fabricated by a doctor-blade method. The incorporation of CN-rGO nanosheets induced a morphological transformation in PVDF, suppressing macropore formation and generating a smoother membrane surface, thereby enhancing hydrophilicity. Crosslinking with 1,5-diamino-2-methylpentane (DAMP) further improves the mechanical strength of the membranes. The resulting macroporeless membranes have exhibited approximately twofold higher water flux than crosslinked PVDF membranes, along with a methylene blue rejection of up to 99%. These results demonstrate that the incorporation of CN-rGO provides the formation of continuous nanoscale pathways in PVDF membranes, promising applications in advanced water treatment.

Photochemical production of hydrogen peroxide (H2O2) using visible light response photocatalysts offers a sustainable green strategy. GA image: Background via Pixabay.com

Layered titanate nanosheets (HT-ns) are potential two-dimensional materials and have wide applications due to their unique structure and low cost. In this study, the HT-ns with different lateral sizes were successfully prepared by exfoliating HT crystals with different lateral sizes, which were prepared by the flux method and ion-exchange reaction. The HT-ns were used to fabricate inorganic nanofiltration membranes by restacking the nanosheets on a porous substrate. The effects of the lateral size of HT-ns on the solute rejection performance and nanostructure of HT-ns membranes (HT-Ms), as well as the effect of surface modification of the substrate on HT-M stability, were investigated. The negatively charged substrate surface was changed to a positively charged surface by surface modification to enhance the bonding between the substrate and HT-ns, which improved the HT-M stability. A series of large-area ultrahydrophilic HT-Ms were fabricated by a facile dry deposition method on surface-modified substrates using the HT-ns with different lateral sizes. The rejection rates for inorganic salts and organic dyes increased with the increase in the lateral size of HT-ns used in HT-M fabrication, and a rejection rate of 99.8% was achieved for rhodamine B. A separation mechanism for HT-Ms was proposed to explain the separation performance, which is also suitable for other metal oxide nanosheet nanofiltration membranes.

Mesoporous anatase TiO₂ mesocrystals with aligned nanostructures exhibit unprecedented photocatalytic and electrochemical performance for advanced applications.

G-C ₃ N ₄ -based materials (CNs) are a promising hydrogen generation photocatalyst for solar energy conversion.

Facet-tailored single-crystalline anatase TiO₂ particles with co-exposed (101)/(001) facets have been widely studied to enhance photocatalysis. Understanding the electronic structure of each facet is paramount for elucidating the charge separation mechanism and improving the photocatalytic performance. In this study, we used X-ray photoelectron spectromicroscopy with a spatial resolution of 100 nm to reveal the electronic structure of each facet of an anatase TiO₂ particle. The analysis revealed smaller core-level binding energies (O 1s and Ti 2p) and lower valence band maximum (VBM) for the (001) relative to the (101) facet of anatase. We also identified an interface structure where the VBM lies between the two facets. Our findings displayed a continuous band bending along the entire interface (~181 nm) of the (101)/(001) facets as the VBM difference (∆E = 0.65 eV). The interface serves as a convenient and rapid pathway for the vectorial transfer of photogenerated electrons and holes to the (101) and (001) facets respectively, thereby offering significant benefits for heterogeneous catalysis applications. This study provides a deeper understanding of facet-dependent properties in anatase, paving the way for the design of more efficient photocatalysts tailored for specific environmental and energy-related applications

Improving the thermal conductivity anisotropy of epoxy/h-BN composites by synthesizing spherical Fe–B_x through carbothermal reduction of iron oxide–boric oxide mixtures (Fe₂O₃–B₂O₃), resulting in the fabrication of spherical h-BN.

Two-dimensional (2D) inorganic nanomaterials have garnered extensive attention in the fabrication of inorganic nanofiltration membranes due to their unique structures and properties. In this study, we developed a facile process for fabricating large-scale ultrahydrophilic nanofiltration membranes using layered titanate H_1.07Ti_1.73O₄·nH₂O nanosheets (HT-ns). A drying deposition process was used to fabricate HT-ns membranes on a poly(tetrafluoroethylene) (TF) substrate. To enhance the bonding strength between the substrate and the deposited HT-ns membrane, the substrate surface was modified with a Cu²⁺-adsorbed silane monomolecular layer, connecting a negatively charged HT-ns membrane and a positively charged substrate surface. The fabricated HT-ns membrane exhibited an excellent rejection performance for inorganic salts and dye molecules. The ultrahydrophilicity of HT-ns membrane with a low water contact angle of 31° results in an ultrafast water permeance, which is approximately 6 times higher than that of a simple graphene-based nanofiltration membrane. The results open a new avenue to a new category of ultrahydrophilic nanofiltration membranes.

As a typical cation-exchangeable layered compound, layered titanate has a unique open layered structure. Its excellent physical and chemical properties allow its wide use in the energy, environmental protection, electronics, biology, and other fields. This paper reviews the recent progress in the research on the structure, synthesis, properties, and application of layered titanates. Various reactivities, as well as the advantages and disadvantages, of different synthetic methods are discussed. The reaction mechanism and influencing factors of the ion exchange reaction, intercalation reaction, and exfoliation reaction are analyzed. The latest research progress on layered titanates and their modified products in the fields of photocatalysis, adsorption, electrochemistry, and other applications is summarized. Finally, the future development of layered titanate and its exfoliated product two-dimensional nanosheets is proposed.