Latest ArticlesMetal-organic frameworks (MOFs) have showed high promise in CO2-electroreduction, yet their generally insufficient conductivity or low electron-transfer efficiency have largely restricted the wide-spread applications. Herein, fullerene molecules (i.e., C60 and C70) have been successfully introduced into the pore-channels of a Co-porphyrin based MOF through a facile strategy. Thus-obtained hybrid materials present higher electron-transfer ability, enhanced CO2 adsorption-enthalpy and CO2 electroreduction activity. Notably, the charge transfer resistance (Rct) of C60@MOF-545-Co is almost 5 times lower of than that of MOF-545-Co, as well as 1.5 times increased for the CO2 adsorption enthalpy. As expect, the FECO of C60@MOF-545-Co (97.0%) is largely higher than MOF-545-Co (70.2%), C60@MOF-545 (19.4%), C60 (11.5%) and physical mixture (70.3%) and presented as one of the best CO2 electroreduction catalysts reported in H-cell system. The facile strategy would give rise to new insight into the exploration of powerful MOF-based hybrid materials in high-efficiency CO2 electroreduction.
A branched core-shell nanosphere composed of an anatase TiO2 (a-TiO2) core and a TiO2 nanobranch shell with gradient-doped N (a-TiO2@N-TiO2) is synthesized by a simple in situ doping method, in which mixed crystal anatase-rutile TiO2 (ar-TiO2) nanosphere is first prepared by oxidizing Ti using H2O2, and then is etched by NH3·H2O to form (NH4)2TiO3 nanobranches, which is converted into a-TiO2@N-TiO2 following an ambient annealing process. The diameter of a-TiO2 core is ~500 nm, and the thickness of N-TiO2 branched shell is ~100 nm with gradually increased N concentration from the bottom to the edge. Ultra-thin amorphous coating layers on the branches are also observed. The morphology of the composites could be further tuned by the amount of NH3·H2O, and its effect on the photocatalytic performance is also investigated. The optimized a-TiO2@N-TiO2 shows an outstanding hydrogen evolution rate of 308.1 µmol g−1 h−1 under air mass (AM) 1.5 illumination, and also exhibits highly active in photocatalytic degradation of various refractory organic pollutants, including organic dyes, phenols, antibiotics, and personal care products, with removal ratios higher than 96% after 2 h operation. This can be due to the gradient-doped N-TiO2 nanobranches, which not only provide bending band structure and defect level derived from the N impurities and O vacancies, resulting the formation of n-n+ heterojunctions to improve the charge separation, but also enhance the charge transfer at the liquid-solid interface due to the numerous nanobranches and amorphous coating layers.
Self-doping cathode interfacial layers (CILs) with both favorable electron injection and transport characteristics meet the key requirement for realizing high-performance optoelectronic devices with simplified structures. Herein, four different polypyridinium salts with tunable backbones, side chains and counter-ions are elaborately designed to afford them desirable film-forming property, polarity, structural rigidity and self-doping feature. All-solution-processed red quantum dot light-emitting diodes (QLEDs) employing them as bifunctional CILs render remarkably improved device performances in contrast to the typical CIL material of poly[(9,9-bis(30-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] (PFN). The maximum external quantum efficiency of 2.74% achieved in this work represents one of the best values among the all-solution-processed QLEDs with individual organic CILs.
Quaternary approach has been receiving more and more attention due to its effectiveness in improving solar cell performance, while synthesis/selection of the fourth component is yet a key issue. Herein, we report a chlorinated phthalimide based donor polymer (namely PhI-Cl) having an ultra-wide bandgap (2.10 eV) and a deep HOMO (−5.58 eV) level. Addition of PhI-Cl as the third component of PM6:Y6 and the fourth of PM6:Y6:PC71BM increases both hole and electron mobilities and gives rise to more balanced charge carriers mobilities. Both the short-circuit current-density and fill-factor are increased and open-circuit voltage is well maintained, delivering 17.0% and 18.1% efficiencies, respectively. These results demonstrate that chlorination on the side thiophene of phthalimide-based donor polymer is a way to make deep HOMO and ultra-wide bandgap donor polymer guest used for highly efficient ternary and quaternary strategies.
Fluorescence detecting both organic and inorganic analytes has aroused tremendous scientific interests, because fluorescence techniques have high sensitivity and are easy to operate. A new three-dimensional (3D) MOF {[(CH3)2NH2][Zn3(bbip)(BTDI)1.5(OH)]·DMF·MeOH·3H2O}n (JXUST-13, bbip = 2,6-bis(benzimidazol-1-yl)pyridine and H4BTDI = 5,5′-(benzo[c][1,2,5]thiadiazole-4,7-diyl)diisophthalic acid) with new 4,4,8-connceted topology has been successfully synthesized and structurally characterized. Importantly, JXUST-13 could recognize H2PO4− and acetylacetone (Acac) by obvious fluorescence blue shift and slight enhancement with the detection limits of 2.70 µmol/L and 0.21 mmol/L, respectively. In addition, JXUST-13 exhibits relatively good thermal stability, chemical stabilities as well as reusability, and the analytes could be distinguished by naked eye and fluorescence test paper. Remarkably, JXUST-13 is the first dual-responsive MOF sensor based on fluorescence blue shift for the detection of H2PO4− and Acac with good selectivity in a handy, economic, and environmentally friendly manner.
Due to its low cost and easy availability, the pitch is considered a promising precursor for soft carbon anodes. However, pitch-derived soft carbon shows a high graphitization degree and small interlayer spacing, resulting in its much lower sodium storage performance than hard carbon. We propose a novel pre-oxidation strategy to introduce additional oxygen atoms into the low-cost soft carbon precursor pitch to fabricate a defect-rich and large-interlayer spacing hard carbon anode (HPP-1100). Compared with the direct pyrolysis of pitch carbon, the sodium storage capacity of HPP-1100 is significantly improved from 120.3 mAh/g to 306.7 mAh/g, with an excellent rate and cycling capability (116.5 mAh/g at 10 C). Moreover, when assorted with an O3-Na(NiFeMn)1/3O2 cathode, the full cell delivers a high reversible capacity of 274.0 mAh/g at 0.1 C with superb cycle life. This work provides a new solution for realizing the application of low-cost pitch anodes in Na-ion batteries.
Conjugated microporous polymers (CMPs) with tunable bandgaps have attracted increasing attention for photocatalytic hydrogen evolution. However, the synthesis of CMPs usually needs expensive metal-based catalysts. Herein, we report a metal-free synthetic route to fabricate pyridyl conjugated microporous polymers (PCMPs) via a condensed polymerization between aldehyde and aryl ketone monomers. The PCMPs show widely tunable specific surface areas (347–418 m2/g), which were controlled via changing the used monomers. The PCMPs synthesized using monomers of dialdehyde and diacetylbenzene (diacetylpyridine) in the presence of pyridine exhibited the highest visible-light driven hydrogen evolution rate (9.56 µmol/h). These novel designed PCMPs provide wide adaptability to current materials designed for high-performance photocatalysts in different applications.
The layered heterometallic halide perovskites, as a newly explored material, have attracted great scientific attention. As one of the representatives of perovskite, lead-free or lead-substituted perovskite materials are widely applied in photovoltaic, sensors, catalysis, detectors and other fields. Therefore, it is urgent to carry out more systematic exploration and expand applicable preresearch, so as to make more interesting discoveries in this new hot spot. As an interesting candidate, heterometallic compounds will introduce more structural adjustability and novel physical properties, which is the main feature to be selected as the research hotspot. Here, we reported a lead-free bilayer heterometallic Ruddlesden-Popper (RP) type perovskite, [(MACH)2CsAgBiBr7] (MACH = cyclohexanemethylamine), which possesses a reversible phase transition at 379.6 K/375.1 K during heating-cooling cycle. Besides, it exhibits reddish-brown light emission under 365 nm, meanwhile, CIE chromaticity coordinate is (0.32, 0.45) on the yellow side and correlated color temperature is about 6000 K. Moreover, both the experimental data and theoretical calculation results suggest that [(MACH)2CsAgBiBr7] shows indirect semiconducting characteristics. In summary, this work will inspire the design of lead-free heterometallic perovskite materials for the application of sensors and light-emitting diodes (LEDs) fields.
The unique components and architecture of Prussian blue analogous (PBAs) offer great potential for the construction of various functional nanostructures. Herein, we reported the preparation of a series of Mn–Fe oxides-based hybrids using Mn–Fe PBA as a template and an organic carbon source by calcination. The study focuses on revealing the interaction between the microstructure and electrochemical performance of the products obtained at different calcination temperatures. Notably, the as-derived porous Fe–Fe0.33Mn0.67O/C nanocubes (i.e., M600) exhibited the best rate capability and cycle life compared with other samples (~890 mAh/g at 0.1 A/g, 626.8 mAh/g after 1000 cycles at 1.0 A/g with a 99% capacity retention). These can be attributed to the fact that the porous structure provides shorter Li+ diffusion path and promotes the penetration of electrolyte. Besides, the N−doped C formed by the carbonization of organic ligands can buffer the volume change and prevent the aggregation of Fe0.33Mn0.67O nanoparticles during the discharge/charge cycles. Moreover, the presence of metallic Fe enhances the conductivity and the electrochemical activity, which accelerates the electrochemical reactions. Therefore, reasonable design of microstructure and compositions of functional nanocomposites is the key to obtain ideal electrochemical properties.
The large consumption and discharge of diclofenac (DCF) lead to its frequent detection in surface water and groundwater, posing great threats to humans and ecosystems. This study explored the oxidation kinetics of DCF by permanganate (Mn(Ⅶ)), and expounded the underlying reason for the unusual pH-dependency that was unclear in previous studies. The kinetics of DCF analogues (i.e., aromatic secondary amines) by Mn(Ⅶ) oxidation were comparatively investigated. Then, a tentative kinetic model involving the formation of an intermediate between Mn(Ⅶ) and DCF or its analogues was proposed to fit the pH-rate profile. Since DCF contained two chloro groups, and a carboxyl group which could be ionized by negative electrospray ionization, a precursor ionization scanning approach was used for the first time for detection of N-containing chlorinated oxidation products. New degradation pathways of DCF containing ring opening, carboxylation, carbonylation, electrophilic addition, hydroxylation and dehydrogenation were proposed based on the identified oxidation products. Moreover, it was demonstrated that the introduction of various reducing agents such as Mn(Ⅱ), Fe(Ⅱ) and bisulfite significantly improved the oxidation kinetics of DCF by Mn(Ⅶ). The positive effects of Mn(Ⅱ) and Fe(Ⅱ) were mainly attributed to the accelerated formation of MnO2 that acted as a catalyst or co-oxidizer contributing to DCF degradation. The presence of bisulfite caused two-stage kinetics, where a sharp drop of DCF concentration followed by a slowdown of DCF removal. In the first stage, potent reactive manganese species (e.g., Mn(Ⅲ), Mn(Ⅴ), and Mn(Ⅵ)) and sulfate radical were generated during reaction of bisulfite with Mn(Ⅶ), whereas bisulfite was depleted fast due to excess Mn(Ⅶ) concentrations and the system became the Mn(Ⅶ)/MnO2 system in the second stage. These results provide new insight into reaction mechanism of DCF with Mn(Ⅶ) as well as propose a feasible strategy for enhancing the treatment of DCF contaminated water by Mn(Ⅶ).
No. 86 Xueyuan South Road, Haidian District, Beijing
010-62199257
qkjq@cast.org.cn
Copyright © 2025 China Association for Science and Technology. All rights reserved. For all open access content, the relevant licensing terms apply.
Sponsored by the Office of the Leading Group for Cybersecurity and Informatization of CAST, and supported by Science and Technology Review Publishing House
