Journal of Colloid and Interface Science最新文献

Porous carbons with large surface area (>3000 m²/g) and heteroatom dopants have shown great promise as electrode materials for zinc ion hybrid capacitors. Centralized mesopores are effective to accelerate kinetics, and edge nitrogen can efficiently enhance pseudocapacitive capability. It is a great challenge to engineer centralized mesopores and edge nitrogen in large-surface-area porous carbons. Herein, a strategy of melamine-boosted K₂CO₃ activation is proposed to prepare edge-nitrogen-doped hierarchical porous carbons (ENHPCs). KOCN generated by K₂CO₃ reacting cyano groups (-CN) couples with K₂CO₃ activation engineers large-surface-area porous carbon. KCN in-situ generated by KOCN etching carbon atoms plays a template role in constructing centralized mesopores. Edge-nitrogen skeleton is formed by g-C₃N₄ losing -CN, and then in-situ integrated into porous carbon skeleton. The efficiency of melamine-boosted K₂CO₃ activation reaches the highest at a melamine/lignin mass ratio of 0.5, where the optimized ENHPCs (ENHPC-0.5) have a large surface area of 3122 m²/g, a mesopore architecture (2.8 nm) with a mesoporosity of 60.5 % and a moderate edge-N content of 1.9 at.%. ENHPC-0.5 cathode displays a high capacitance of 350F/g at 0.1 A/g, an excellent rate capability of 129F/g at 20 A/g and a robust cycling life. This work provides a novel strategy to prepare heteroatom-doped high-surface-area porous carbons for zinc ion hybrid capacitors.

Modern microelectronics industries urgently require dielectric materials with low thermal expansion coefficients, low dielectric constants, and minimal dielectric loss. However, the design principles of materials with low dielectric constants and low thermal expansion are contradictory. In this study, a new diamine monomer containing a dibenzocyclooctadiene unit (DBCOD-NH₂) was designed and synthesized, which was subsequently polymerized with high fluorine content 4,4'-hexafluoroisopr-opylidene diphthalic anhydride and 4,4'-diamino-2,2'-bis(trifleoromethyl)biphenyl to obtain a series of fluorinated polyimides (PIs). Due to the unique conformational transition of the eight-membered carbon ring, the resulting PI can reach a low averaging thermal expansion coefficient (CTE) of only 12.27 ppm/K over 5-150 ℃ with a size change rate of only 0.16 %. Surprisingly, the synergistic effect of DBCOD-NH₂ with the other two monomers enhances the dielectric performance of the PIs. At an electric field frequency of 10 MHz, the dielectric constant (D_k) and the dielectric loss (D_f) can be reduced to as low as 2.61 and 0.00194, respectively. The strategy used herein largely tackles the challenge of balancing low D_k with low CTE. Furthermore, these PI films also exhibit good thermal stability (with 5 wt% weight loss temperatures ranging from 453 to 537 ℃ in N₂, and glass transition temperatures of 305-337 ℃) and robust mechanical properties (with a tensile modulus of 1.88-2.29 GPa and an elongation at break of 6.36-8.11 %). The combination of low thermal expansion and excellent dielectric properties renders these PIs highly promising for applications in the microelectronics and telecommunications industries.

The simultaneous generation of hydrogen (H₂) and the oxidative transformation of organic molecules through photocatalytic processes represents a highly promising dual-purpose strategy. This approach obviates the necessity for sacrificial agents while augmenting catalytic efficiency, thereby facilitating the integrated production of high-value chemicals and renewable energy carriers. Polymeric carbon nitride (PCN) has emerged as a leading candidate among coupled photocatalysts. Nevertheless, PCN's efficacy is constrained by the inefficient separation of charges and the functional limitations of its active sites. Herein, the incorporation of P-N₃ groups into PCN introduces active sites with pronounced charge asymmetry, resulting in strong local charge polarization. This asymmetric charge distribution, mediated by the P-N₃ groups, significantly enhances exciton dissociation. Remarkably, the P-N₃-modified narrow-dimensional fragmented carbon nitride (P-CNNS) achieves an 85 % conversion rate for 4-MBA with nearly 100 % selectivity, and a hydrogen evolution rate of 27.9 mmol g^-1 (with Pt as a co-catalyst), representing 6.2 times higher than that of bulk carbon nitride (BCN). The charge-polarized sites facilitate the transfer of electrons, which is a pivotal process in the activation of 4-methoxybenzyl alcohol (4-MBA). Additionally, these sites serve as adsorption sites, facilitating the oxidation of 4-MBA into anisaldehyde (AA). This work underscores the potential of non-metallic site catalysts for a wide range of coupled photocatalytic applications.

Rational regulation of interface structure in photocatalysts is a promising strategy to improve the photocatalytic performance of carbon dioxide (CO₂) reduction. However, it remains a challenge to modulate the interface structure of multi-component heterojunctions. Herein, a strategy integrating heterojunction with facet engineering is developed to modulate the interface structure of metal-organic frameworks (MOF)-based heterojunctions. A series of core-shell UiO-66 (Zr-MOF)-loaded MIL-125 (Ti-MOF) heterojunctions with exposed specific facets were prepared to enhance the separation efficiency of photogenerated electrons-holes in CO₂ photoreduction. Impressively, MIL-125_to@UiO-66 with exposed {1 1 1} facet exhibits an excellent CO production rate (56.4 μmol g^-1 h^-1) and selectivity (99 %) under visible light irradiation without any photosensitizers/sacrificial agents, being 1.4 and 11.3 times higher than individual MIL-125_to and UiO-66, respectively. The type-II heterojunction significantly enhances the separation of photogenerated electrons-holes in physical space. The photogenerated electrons migrate from Zr in UiO-66 to Ti in MIL-125_to, promoting a spatial synergy between CO₂ reduction on MIL-125_to and H₂O oxidation on UiO-66. Compared with MIL-125_rd@UiO-66 with exposed {1 1 0} facet and MIL-125_ds@UiO-66 with exposed {0 0 1} facet, MIL-125_to@UiO-66 with exposed {1 1 1} facet improves the exposure of surface-active Ti sites, thereby enhancing the adsorption/activation of CO₂ to generate the *COOH intermediate. This work provides an effective strategy for designing MOF-based heterojunction photocatalysts to improve photocatalytic performance.

The limited transport of oxygen at the solid-liquid interface and the poor charge separation efficiency of single catalyst significantly impedes the generation of reactive oxygen species (ROS), thereby weakening the application potential of photocatalytic technology in water pollution control. Herein, a hollow porous photocatalytic aerogel sphere (calcium alginate/cellulose nanofibers (CA/CNF)) loaded BiOBr/Ti₃C₂, combining a favourable mass transfer structure with effective catalytic centers was firstly presented. The floatability and hollow pore structure facilitated rapid O₂ transfer via a triphase interface, thereby promoting the generation of ROS. The oxygen diffusion flux of aerogel spheres' upper surface in triphase system exhibited a 0.151 μmol·(m²·S)^-1 increase compared to that of the diphase one based on Finite element simulation (FEM). Furthermore, owing to the regulation of charge spatial distribution by Schottky junction of BiOBr/Ti₃C₂, internal electric field (IEF) of CA/CNF@BiOBr/Ti₃C₂ achieved 1.8-fold improvement compared with CA/CNF@BiOBr, thus enhancing the separation of photogenerated charges. Accordingly, the degradation efficiency and catalytic rate constant of moxifloxacin (MOX) by CA/CNF@BiOBr/Ti₃C₂ in triphase system have improved by 20.1% and 1.5 times compared to those of diphase system, respectively. Moreover, the potential to mineralize multiple quinolone antibiotics (FQs), high resistance to complex water disturbances and excellent stability were revealed in CA/CNF@BiOBr/Ti₃C₂. Besides, the triphase system based on CA/CNF@BiOBr/Ti₃C₂ confirmed the potential for large-scale water treatment application in 500 mL MOX circular flow, reaching 90% MOX removal within 120 min. This research clarifies the oxygen mass transfer mechanism and pathways to the enhanced ROS production in a triphase system, and provides new insights into designing efficient floatable photocatalyst and adaptive reaction devices for new pollutants remediation.

Poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS) has been widely used as the hole transport layers (HTLs) for perovskite solar cells (PSCs), especially in all-perovskite tandems. However, the energy-level mismatch between PEDOT:PSS and perovskite leads to large voltage deficit in PSCs, and the dopant PSS with high acidity and hygroscopicity conspicuously deteriorates the device stability. Herein, a powerful strategy for constructing self-assembled polymer HTLs is developed by in-situ polymerization of functionalized 3,4-ethylenedioxythiophene with carboxylic acids as side groups. This strategy facilitates the formation of a self-assembled polymer monolayer to be strongly anchored on the glass substrate, and enables the elimination of the dependence of PSS doping for traditional PEDOT. The obtained polymer HTL PEDOT-l-COOH (PTLC) exhibits an appropriate energy-level alignment with the perovskite, which enhances the charge carrier collection at the interfaces. Besides, the self-assembled PTLC with high structural ordering favors the heterogeneous nucleation of perovskite, resulting in the formation of high-quality perovskite films with superior buried interfaces. Consequently, the inverted PSCs based on PTLC demonstrate a champion conversion efficiency of 20.30 % with a high open-circuit voltage of 1.03 V which are much higher than that of PEDOT:PSS-based devices (14.47 %, 0.79 V). More encouragingly, the unsealed devices with PTLC deliver outstanding operational stability by maintaining 90 % of initial efficiency for 950 h under ambient condition with a relative humidity of 30 % ± 5 %. This work opens a new avenue for developing self-assembled PEDOT-based HTLs for optoelectronic devices, and paves the way for further improving the performance of inverted PSCs.