Latest ArticlesThermoelectric (TE) materials enable effective and direct energy conversions between heat and electricity, displaying wide applications including waste/low-grade heat harvesting, local cooling, sensing and wearable electronics. Among the recently-developed organic and composite TE materials, poly(3,4-ethylenedioxythiophene) (PEDOT) is perhaps the most successful and frequently reported type. Herein, we aim to review the recent advances of the synthesis, mechanism and applications of PEDOT-based TE composites. First, the research background and the history of TE materials are briefly introduced. Next, the synthesis and TE performance of PEDOT-based composites are summarized according to the sequence of films, hydrogels/aerogels and fibers/yarns. Then, the mechanism, structure and property are elucidated. After that, the recent development and its applications of power generation and sensing are highlighted. Finally, we provide an outlook on the prospects and the challenges of PEDOT-based TE composites.
On-surface Ullmann-type reaction, or the dehalogenated coupling, is arguably the most pivotal reaction in on-surface synthesis for the fabrications of carbon nanostructures. Hitherto, the vast majority of works rely on activating the C-Br bond of aryl bromide which has a moderate bond dissociation energy. The C-Cl bond of aryl chloride has a higher dissociation energy and requires much higher thermal energy to break the bond. In this study, we have explored the on-surface photo-induced dechlorination and achieved the activation of three distinct aryl chlorines on the Au(111) surface with mild temperatures. This work enriches our understanding of on-surface photo-induced reactions and highlights the potential of photochemistry in realizing unconventional reactions.
Biomass absorbing materials have received increasing attention for electromagnetic wave (EMW) absorption field absorbing materials due to its low density and high dielectric loss. However, the biomass EMW absorbing materials often suffer from the insufficient magnetic loss and impedance matching. In this work, a facile ZIF-8/ZIF-67-derived biomass composites (CoZnO@BPC) was prepared for high-performance EMW absorption based on multi-component micro, nano structures metal particles and xanthoce sorbifolia bunge shells-derived biomass porous carbon (BPC). The dielectric loss and/or magnetic loss abilities of CoZnO@BPC composites were adjusted by changing the mass ratio of Zn2+ to Co2+ ions. Under the filled amount of 20 wt%, CoZnO@BPC exhibited excellent EMW absorption with the minimum reflection loss (RL) at 15.84 GHz is -50.2 dB, and the matching thickness is only 1.7 mm. By adjusting the ZIFs mass ratio, the effective absorption bandwidth (EAB) can be up to 5.92 GHz (from 12.08 GHz to 18 GHz), and the matching thickness is only 1.9 mm. The results provide a new insight for the economical and efficient preparation of lightweight and advanced microwave absorbing materials.
Acidification of paper-based relics is a common problem, leading to their degradation and eventual loss. Paper deacidification is highly dependent on a limited variety of alkaline materials, and the development of new materials that are safe, efficient and easy-to-prepare is highly demanded to ensure a high level of safety and effective protection of paper-based relic. This study proposes the introduction of layered double hydroxide (LDH) and its calcined product, mixed metal oxide (layered double oxide (LDO)), as innovative protective materials for the deacidification of paper with varying levels of acidity. The results demonstrate that treatment with Mg-Al LDH/LDO can effectively modify the pH of acidic paper (e.g., pH ~ 4.0–6.4) to a neutral or weakly basic state, maintaining this desirable pH range even under long-term accelerated aging condition. Remarkably, LDH proves to be well-suited for the protection of slightly acidified paper (e.g., pH > 5.5), while LDO serves as an especially option for the deacidification of severely acidified paper (e.g., pH ≤ 5.5). During aqueous deacidification, due to the memory effect of the LDH-based materials, LDO is converted to rehydrated LDH, which creates a mild and appropriate alkaline retention in the paper, avoiding damage caused by strong alkalinity such as cellulose degradation and pigment fading during subsequent long-term natural preservation of the paper. Furthermore, Mg-Al LDH/LDO materials also exhibit flame-retardant and bacteriostatic properties. This opens up opportunities for the safe, efficient and multifunctional protection of acidified paper-based relics.
The Na-deficient P3-type layered oxide cathode material usually experience complex in-plane Na+/vacancy ordering rearrangement and undesirable P3-O3 phase transitions in the high-voltage region, leading to inferior cycling performance. Additionally, they exhibit unsatisfactory stability when exposed to water for extended periods. To address these challenges, we propose a Cu/Ti co-doped P3-type cathode material (Na0.67Ni0.3Cu0.03Mn0.6Ti0.07O2), which effectively mitigates Na+/vacancy ordering and suppresses P3-O3 phase transitions at high voltages. As a result, the as-prepared sample exhibited outstanding cyclic performance, with 81.9% retention after 500 cycles within 2.5–4.15 V, and 75.7% retention after 300 cycles within 2.5–4.25 V. Meanwhile, it demonstrates enhanced Na+ transport kinetics during desodiation/sodiation and reduced growth of charge transfer impedance (Rct) after various cycles. Furthermore, the sample showed superb stability against water, exhibiting no discernible degradation in structure, morphology, or electrochemical performance. This co-doping strategy provides new insights for innovative and prospective cathode materials.
The electrochemical oxidation of 5-hydroxymethylfurfural (HMF) to valuable chemicals is an efficient way to upgrade biomass molecules and replace traditional catalytic synthesis. It is crucial to develop efficient and low-cost earth-abundant electrocatalysts to enhance catalytic performance of HMF oxidation. Herein, a new type of two-dimensional (2D) hybrid arrays consisting of NiFe layered double hydroxides (LDH) nanosheets and bimetallic sulfide (NiFeS) is constructed via interface engineering for efficient electrocatalytic oxidation of HMF to 2, 5-furandicarboxylic acid (FDCA). The preparation process of 2D NiFe LDH/NiFeS with ultrathin heterostructure involves in anchoring a Co-based metal-organic framework (Co MOF) as template onto the carbon cloth (CC) via in-situ growth, formation of NiFe LDH on the surface of Co MOF and subsequent partial sulfidation. The electrocatalyst of NiFe LDH/NiFeS exhibits outstanding performance towards HMF oxidation, about 98.5% yield for FDCA and 97.2% Faraday efficiency (FE) in the alkaline electrolyte with 10 mmol/L HMF, as well as excellent stability retaining 90.1% FE for FDCA after six cycles test. Moreover, even at an HMF concentration of 100 mmol/L, the yield and FE for FDCA remain high at 83.6% and 93.6%, respectively. These findings highlight that 2D heterostructure containing abundant interfaces between NiFe LDH nanosheets and NiFeS can enhance the intrinsic activity of LDH and thus promote the oxidation reaction kinetics. Additionally, the synergistic effect of the bimetallic NiFe compounds also improved the selectivity of HMF conversion to FDCA. Our present work demonstrates that constructing 2D ultrathin heterostructure of NiFe LDH/NiFeS is a facile strategy via interface engineering to enhance the intrinsic activity of LDH electrocatalysts, which would open new avenues toward low-cost and advanced 2D nanocatalysts for sustainable energy conversion and electrochemical valorization of biomass derivatives.
Under the guidance of the approach which integrates molecular networking, MolNetEnhancer and Network Annotation Propagation (NAP), daphnaltaicanoids A and B (1 and 2) with unprecedented 9-oxa-tetracyclo[6.6.1.02,6.08,13]pentadecane and tetracyclo[5.3.0.12,5.24,11]tridecane central frameworks were isolated from Daphne altaica Pall., representing two types of unparalleled meroterpenoid cores. Their structures were elucidated by extensive spectroscopic analysis, nuclear magnetic resonance (NMR) calculations, DP4+ analysis and electronic circular dichroism (ECD) calculations. The plausible biosynthetic pathways for 1 and 2 were postulated. Biologically, 2 exerted potent neuroprotective activities which were superior to trolox at 12.5 and 25 µmol/L. Moreover, 1 and 2 exhibited more noticeable acetylcholinesterase inhibitory activities than donepezil. Molecular docking simulations were performed to explore the intermolecular interaction of compounds 1 and 2 with acetylcholinesterase. The bioactivity evaluation results highlight the prospects of 1 and 2 as a novel category of neurological agents.