Latest ArticlesParticle engineering has opened the floodgates to material science in both fundamental and application field. However, covalent interactions have not yet been adequately designed in the particle engineering for functional colloidal photonic crystals (CPCs). Herein, we achieved covalent coupling between carboxyl-rich poly(styrene-acrylic acid) (P(St-AA)) monodispersed colloidal particles and amine-rich carbon dots (CDs) based on an feasible and universal particle engineering strategy. The designed CDs-grafted P(St-AA) monodispersed colloidal particles initiate a hydrogen bond-driven assembly mode and ensure the construction of large-scale crack-free CPCs. Moreover, the CDs equipped with selective broad-band absorption capacity could improve the saturation of structural colors for high-visibility CPCs. Furthermore, an injectable photonic hydrogel (IPH) is developed to design CPC supraball hydrogel via integrating the CDs-grafted P(St-AA) CPC supraballs with supramolecular hydrogel. Combining superior flexibility, sufficient self-healing capacity of supramolecular hydrogel with visual optical information of our CPC supraballs, a cyclically reversible coding and decoding system was developed. Meanwhile, we firstly demonstrated the novel strategy of 3D supraballs-based passive cooling. The designed 3D CPC supraball hydrogel presents nearly full observation angle reflections behavior and excellent water evaporation capacity and achieves 3.6 ℃ temperature drops, showing the application advantages in 3D thermal management. This work not only provides a new insight for manipulating optical properties of CPCs, but also demonstrates an easy-to-perform platform, as well as indicates the direction for the promising application of CPCs.
Converting CO2 into value-added chemicals and fuels through various catalytic methods to lower the atmospheric CO2 concentration has been developed to be a crucial means to alleviate the energy shortage and ameliorate the ever-fragile environment status. However, the complexity of the CO2 conversion reaction and the strong reduction conditions lead to the inevitable structural evolution, making it difficult for the prior design of suitable catalytic materials. Herein, to guide the rational design of efficient catalysts, we will be centered on the thermal, electro, and photo-induced structural evolution and active species identification during the CO2 conversion, including the in situ/operando characterization techniques monitoring the activation, steady, and deactivation stage of the catalysts as well as the inherent restructuring mechanism towards active species. Besides, the future challenges and opportunities on the merits of combining the structural evolution with the adsorbed intermediates recognized by ultra-fast spectroscopic techniques, simultaneously, the combination of theoretical simulation and the results of in situ experiments will also be addressed. This review can not only guide the identification of real active species, but also provide an approach to design the specific active species towards CO2 conversion, rather than only focusing on activity, for the purpose of practical industrial application.
Achieving a high carrier migration efficiency by constructing built-in electric field is one of the promising approaches for promoting photocatalytic activity. Herein, we have designed a donor-acceptor (D-A) crystalline carbon nitride (APMCN) with 4-amino-2,6-dihydroxypyrimidine (AP) as electron donor, in which the pyrimidine ring was well embedded in the heptazine ring via hydrogen-bonding effect during hydrothermal process. The APMCN shows superior charge-transfer due to giant built-in electric field (5.94 times higher than pristine carbon nitride), thereby exhibiting excellent photocatalytic H2 evolution rate (1350 µmol/h) with a high AQY (62.8%) at 400 nm. Mechanistic analysis based on detailed experimental investigation together with theoretical analysis reveals that the excellent photocatalytic activity is attributed to the promoted charge separation by the giant internal electric field originated from the D–A structure.
Hydrogen has emerged as a promising environmentally friendly energy source. The development of low-cost, highly active, stable, and easily synthesized catalysts for hydrogen evolution reactions (HER) remains a significant challenge. This study explored the synthesis of nitrogen-doped MXene-based composite catalysts for enhanced HER performance. By thermally decomposing RuCl3 coordinated with melamine and formaldehyde resin, we successfully introduced nitrogen-doped carbon (NC) with highly dispersed ruthenium (Ru) onto the MXene surface. The calcination temperature played a crucial role in controlling the size of Ru nanoparticles (Ru NPs) and the proportion of Ru single-atom (Ru SA), thereby facilitating the synergistic enhancement of HER performance by Ru NPs and Ru SA. The resulting catalyst prepared with a calcination temperature of 600 ℃, Ti3C2Tx-N/C-Ru-600 (TNCR-600), exhibited exceptional HER activity (η10 = 17 mV) and stability (160 h) under alkaline conditions. This work presented a simple and effective strategy for synthesizing composite catalysts, offering new insights into the design and regulation of high-performance Ru-based catalysts for hydrogen production.
High-temperature proton exchange membranes (HT-PEMs) possess excellent thermal and outstanding electrochemical stability, providing an avenue to realize high-temperature proton exchange membranes fuel cells (HT-PEMFCs) with both superior power density and long-term durability. Unfortunately, polybenzimidazole (PBI), a typical material for conventional HT-PEMs, fails to compromise the high nonaqueous proton conductivity and high mechanical properties, thus hindering their practical applications. Achieving efficient nonaqueous proton conduction is crucial for HT-PEMFC, and many insightful research works have been done in this area. However, there still lacks a report that integrates the host-guest interactions of phosphoric acid doping and the structural stability of polymers to systematically illustrate modification strategies. Here, we summarize recent advancements in enhancing the nonaqueous proton conduction of HT-PEMs. Various polymer structure modification strategies, including main chain and side group modification, cross-linking, blocking, and branching, are reviewed. Composite approaches of polymer, including compounding with organic porous polymers, filling the inorganic components and modifying with ionic liquids, etc., are also covered in this work. These strategies endow the HT-PEMs with more free volume, nanophase-separated structure, and multi-stage proton transfer channels, which can facilitate the proton transportation and improve their performance. Finally, current challenges and future directions for further enhancements are also outlined.
Realizing high-rate capability and high-efficiency utilization of polyanionic cathode materials is of great importance for practical sodium-ion batteries (SIBs) since they usually suffer from extremely low electronic conductivity and limited ionic diffusion kinetics. Herein, taking Na3.5V1.5Mn0.5(PO4)3 (NVMP) as an example, a reinforced concrete-like hierarchical and porous hybrid (NVMP@C@3DPG) built from 3D graphene ("rebar") frameworks and in situ generated carbon coated NVMP ("concrete") has been developed by a facile polymer assisted self-assembly and subsequent solid-state method. Such hybrids deliver superior rate capability (73.9 mAh/g up to 20 C) and excellent cycling stability in a wide temperature range with a high specific capacity of 88.4 mAh/g after 5000 cycles at 15 C at room temperature, and a high capacity retention of 97.1% after 500 cycles at 1 C (−20 ℃), and maintaining a high reversible capacity of 110.3 mAh/g in full cell. This work offers a facile and efficient strategy to develop advanced polyanionic cathodes with high-efficiency utilization and 3D electron/ion transport systems.
Sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs) are the most promising alternatives to lithium-ion batteries, and thus have drawn intensive research attention. Porous carbon materials from different precursors have been widely used as anode materials owing to their compatible storage effectiveness of both larger radii sodium and potassium ions. However, the differential bonding behaviors of Na and K ions with porous carbon-based anode are the significant one worth investigating, which could provide a clean picture of alkali ions storage mechanism. Therefore, in this work, we prepare a porous carbon network derived from sawdust (SDC) wastes, to further analyze the differences on sodium and potassium ions storage behaviors in terms of bond-forming process. It is found that, as-prepared SDC anodes could deliver stable sodium and potassium storage capacities, however, there are notable distinctions in terms of electrochemical behaviors and diffusion processes. By virtue of ex-situ XRD and Raman spectroscopy, the phase transition reaction of potassium ions could be well-observed, and the results shows that the multiple intercalated compounds was formed in SDC network during ions insertion, further resulting in slower diffusion kinetics and larger resistance compared to non-bonded process of sodium ions storage. This study provides more insights into the differences between sodium and potassium ions storage, as well as the energy storage mechanism of porous carbon as anodes for secondary batteries.
Two distinctive rearranged 19-nor-7,8-seco-labdane diterpenoids (1 and 2) with a novel tetracyclo[5.2.1.02,5.04,10]decane skeleton, a derivative of the open tetrahydrofuran ring (7), three dimeric compounds (8−10), and four revised homologs (3−6) were obtained from Chinese liverwort Pallavicinia ambigua. Their structures were identified via combined analysis of their spectroscopic data, single-crystal X-ray diffraction patterns, and ECD calculations. The light-driven conversion of compound 5 to compounds 1−4 demonstrated that photochemically induced postmodification involved in biosynthesis is an important way to diversify natural structures. A preliminary cytotoxicity assay revealed that compound 5 showed significant inhibition in the human prostate cancer (PC-3) cell line via an apoptotic pathway.
As a common active substructure, hydrazone has attracted increasing attention and is considered essential for pesticide discovery. It has been widely regarded as a potential insecticidal, antibacterial, antifungal, antiviral, and herbicidal agent. In this review, we highlight the pesticide versatility of hydrazone fragments and provide a comprehensive summary of the biological activity, structure-activity relationship analysis (SARs), and primary mechanism of their analogs. This profile is expected to give valuable information for discovering new pesticides.
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