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SnSe@N-HCNs yolk–shell nanocages made from confined replacement strategy has strong interfacial chemical bonding interaction and stable porous structure, enabling remarkably improved charge transfer kinetics and ion storage capacity.

Up-converted self-trapped exciton luminescence via seven-phonon absorption in the Na/Bi-alloyed Cs2AgInCl6 lead-free double perovskite is reported.

The kinetics incompatibility between battery-type anode and capacitive-type cathode for sodium ion hybrid capacitors (SIHCs) seriously hinders their overall performance output. Herein, we construct a SIHCs device by coupling with quantum grade vanadium nitride (VN) nanodots anchored in one-dimensional N/F co-doped carbon nanofiber cages hybrids (VNQDs@PCNFs-N/F) as the freestanding anode and the corresponding activated N/F co-doped carbon nanofiber cages (APCNFs-N/F) as cathode. The strong coupling of VN quantum dots with N/F co-doped 1D conductive carbon cages effectively facilitates the ion/electron transport and intercalation-conversion-deintercalation reactions, ensuring fast sodium storage to surmount aforesaid kinetics incompatibility. Additionally, density functional theory calculations cogently manifest that the abundant active sites in the VNQDs@PCNFs-N/F configuration boost the Na

Small molecular acceptors have been successfully synthesized via solvent-free ball milling Knoevenagel condensation in air with ammonium acetate as the catalyst.

MOF-derived NiCo2S4 nanoparticles and hollow carbon hybrid spheres compactly concatenated by electrospun carbon fibers have been successfully synthesized and employed as self-standing cathode electrodes for aqueous alkaline Zn batteries.

Bismuth sulfide (Bi2S3) has attracted particular interest as a potential anode material for sodium-ion batteries (SIBs). However, the low electrical conductivity and dramatic volumetric change greatly restrict its practical applications. In view of the apparent structural and compositional advantages of metal-organic frameworks (MOFs) derived carbon-based composite, herein, as a proof of concept, Bi2S3 spheres coated with the MOF-derived Co9S8 and N-doped carbon composite layer (Bi2S3@Co9S8/NC composite spheres) have been rational designed and synthesized. As expected, the core-shell Bi2S3@Co9S8/NC composite spheres exhibit remarkable electrochemical performance in terms of high reversible capacity (597 mAh g−1 after 100 cycles at 0.1 A g−1), good rate capability (341 mAh g−1 at 8 A g−1) and long-term cycling stability (458 mAh g−1 after 1000 cycles at 1 A g−1) when investigated as anode materials for SIBs. Electrochemical analyses further reveal the favorable reaction kinetics in the Bi2S3@Co9S8/NC composite spheres. In addition, the possible sodium storage mechanism has been studied by ex-situ X-ray diffraction technique. More importantly, a sodium-ion full cell based on Na3V2(PO4)3/rGO as cathode and Bi2S3@Co9S8/NC as anode is also fabricated, suggesting their potential for practical applications. It is anticipated that the present work could be extended to construct other advanced electrode materials using MOFs-derived carbon-based composites as surface coating materials for various energy storage-related applications.

A metal–organic framework (MOF) thin film constructed from Zn nodes and naphthalenediimide (NDI) linkers was grown in-situ uniformly on a transparent conducting glass substrate. This transparent thin film exhibits intriguingly high-contrast electrochromic (EC) switching between canary yellow and dark brown by means of a one-electron redox reaction at its NDI linkers. The findings provide a basic comprehension of the relations between redox state and electrochromism and enrich the application of MOF in the field of optoelectronic materials.

Covalent organic frameworks (COFs) have been extensively investigated due to their unique structure, porosity, and functionality. However, at the topological level, COFs remain as two-dimensional (2D) or three-dimensional (3D) structures, while COFs with one-dimensional (1D) topology have not been systematically explored. In this work, we proposed a synthetic strategy for the construction of 1D-COFs based on non-linear edges and suitable high-symmetry vertices. Compared with their 2D-COFs counterparts, the 1D-COFs with AIEgens located at the vertex of the frame exhibited enhanced fluorescence. The density functional theory (DFT) calculations revealed that the dimensional-induced rotation restriction (DIRR) effect could spontaneously introduce additional non-covalent interactions between the strip frames, which could substantially diminish non-radiative transitions. This work also provides protocols for the design of 1D-COFs and a guidance scheme for the synthesis of emitting COFs.

Sodium based dual-ion battery (SDIB) has been regarded as one of the promising batteries technologies thanks to its high working voltage and natural abundance of sodium source, its practical application yet faces critical issues of low capacity and sluggish kinetics of intercalation-type graphite anode. Here, a tubular nanohybrid composed of building blocks of carbon-film wrapped WS

Searching for high-performance Ni-based cathodes plays an important role in developing better aqueous nickel-zinc (Ni-Zn) batteries. For this purpose, herein, we demonstrate the design and synthesis of ultrathin α-Ni(OH)2 nanosheets branched onto metal-organic frameworks (MOFs)-derived 3D cross-linked N-doped carbon nanotubes encapsulated with tiny Co nanoparticles (denoted as Co@NCNTs/α-Ni(OH)2), which are directly supported on a flexible carbon cloth (CC). An aqueous Ni-Zn battery employing the hierarchical CC/Co@NCNTs/α-Ni(OH)2 as the binder-free cathode and a commercial Zn plate as the anode is fabricated, which displays an ultrahigh capacity (316 mAh g-1) and energy density (540.4 Wh kg-1) at 1 A g-1 as well as excellent rate capability (238 mAh g-1 at 10 A g-1) and superior cycling performance (about 84% capacity retention after 2000 cycles at 10 A g-1). The impressive electrochemical performance might benefit from the rich active sites, rapid electron transfer, cushy electrolyte access, rapid ion transport, and robust structural stability. In addition, the quasi-solid-state CC/Co@NCNTs/α-Ni(OH)2//Zn batteries are also successfully assembled with polymer electrolyte, indicating the great potential for portable and wearable electronics. This work might provide important guidance for constructing carbon-based hybrid materials directly supported on conductive substrates as high-performance electrodes for energy-related devices.

Developing high-performance cathode host materials is fundamental to solve the low utilization of sulfur, the sluggish redox kinetics, and the lithium polysulfide (LiPS) shuttle effect in lithium-sulfur batteries (LSBs). Here, a multifunctional Ag/VN@Co/NCNT nanocomposite with multiple adsorption and catalytic sites within hierarchical nanoreactors is reported as a robust sulfur host for LSB cathodes. In this hierarchical nanoreactor, heterostructured Ag/VN nanorods serve as a highly conductive backbone structure and provide internal catalytic and adsorption sites for LiPS conversion. Interconnected nitrogen-doped carbon nanotubes (NCNTs), in situ grown from the Ag/VN surface, greatly improve the overall specific surface area for sulfur dispersion and accommodate volume changes in the reaction process. Owing to their high LiPS adsorption ability, outer Co nanoparticles at the top of the NCNTs catch escaped LiPS, thus effectively suppressing the shuttle effect and enhancing kinetics. Benefiting from the multiple adsorption and catalytic sites of the developed hierarchical nanoreactors, Ag/VN@Co/NCNTs@S cathodes display outstanding electrochemical performances, including a superior rate performance of 609.7 mAh g-1 at 4 C and a good stability with a capacity decay of 0.018% per cycle after 2000 cycles at 2 C. These properties demonstrate the exceptional potential of Ag/VN@Co/NCNTs@S nanocomposites and approach LSBs closer to their real-world application.

We study the structure, crystallization, and performances of the sealing glasses with the composition (mol.%) of 12Al2O3·8B2O3·40SiO2·40RO (R = Mg, Ca, Sr) for solid oxide fuel cells (SOFCs) before and after isothermal treatment at 700°C, which is within the operation temperature range (600-800°C) of SOFCs. The crystallization behavior has been investigated by differential scanning calorimetry and X-ray diffraction under both dynamic and isothermal conditions. The structural evolution is probed using the Raman and nuclear magnetic resonance spectroscopies. The performances of the sealing glasses are characterized in terms of the coefficient of thermal expansion, the crystallization-induced stress at glass–steel interface. We find that strong crystallization occurs at the operation temperature (700°C) far below the crystallization onset temperature measured by DSC. The structure origin of this anomalous crystallization is discussed in terms of structural heterogeneity of the three studied glasses. We determine the residual stress at the interface between the Ca-containing glass and the steel after isothermal treatment at 700°C for 48 h, but this stress does not lead to falling off the glass layer from the steel. This indicates that this glass is a good candidate to be applied in SOFCs.

The efficient nondestructive assessment of quality and homogeneity for two-dimensional (2D) MoS2 is critically important to advance their practical applications. Here, we presented a rapid and large-area assessment method for visually evaluating the quality and uniformity of chemical vapor deposition (CVD)-grown MoS2 monolayers simply with conventional optical microscopes. This was achieved through one-pot adsorbing abundant sulfur particles selectively onto as-grown poorer-quality MoS2 monolayers in a CVD system without any additional treatment. We further revealed that this favorable adsorption of sulfur particles on MoS2 originated from their intrinsic higher-density sulfur vacancies. Based on unadsorbed MoS2 monolayers, superior performance field effect transistors with a mobility of ∼49 cm2 V-1 s-1 were constructed. Importantly, the assessment approach was noninvasive due to the all-vapor-phase and moderate adsorption-desorption process. Our work offers a new route for the performance and yield optimization of devices by quality assessment of 2D semiconductors prior to device fabrication.

Sodium–ion hybrid capacitors (SIHCs) hold great promise in large-scale energy storage by compromising the merits of sodium–ion batteries and electrochemical capacitors; however, the mismatch of kinetics and capacity between battery-type anode and capacitive-type cathode is still the Achilles’ heel of this technology. Herein, nanohybrids with Mn single atoms implanted in N, F co-doped ultrathin porous carbon nanosheets (MnSAs/NF-CNs) have been developed as both the anode and cathode of SIHCs. The systematic experimental study coupled with theoretical calculations reveal that N-coordinated Mn atoms (Mn–N4) can act as sites not only for reversible Na+ storage with reduced energy barrier but also for improving the pseudocapacitance, thus making great contribution to accelerating the reaction kinetics of the anode and enhancing the capacity for the cathode in SIHCs. We demonstrate that the Janus-featured MnSAs/NF-CNs endows SIHCs with an impressively high energy/power density (maximum 197 W h kg−1/9350 W kg−1) and ultralong cycling life over 10 000 cycles.

Vanadium(V)-based cathode materials hold great potential for rechargeable aqueous zinc-ion batteries (AZIBs). However, the shortcomings of poor electrical conductivity, large volume changes, serious V dissolution and the complicated electrochemical reaction mechanism seriously restrict their practical applications. Herein, we demonstrate the synthesis of unique amorphous Mo–V–O and Mo–V–N hybrid nanoplate arrays directly grown on a carbon cloth substrate (CC@a-MVO/MVN HNPAs) as an additive- and binder-free cathode for AZIBs. This electrode design offers multiple advantages including high electrical conductivity, abundant active sites, favorable ion diffusion kinetics and robust mechanical stability. As expected, the CC@a-MVO/MVN cathode exhibits outstanding performance in terms of high discharge capacity (1.06 mA h cm−2 at a current density of 0.5 mA cm−2), good rate capability (0.67 mA h cm−2 at 10 mA cm−2) and exceptional long-term cycle stability (94% capacity retention at 6 mA cm−2 for 2000 cycles). Furthermore, flexible soft-packaged AZIBs are successfully assembled to demonstrate their ability for practical applications. More importantly, various ex situ characterization studies reliably demonstrate the reversible formation/decomposition of two different kinds of zinc-containing byproducts, which could correspond to the H+/Zn2+ co-insertion mechanism. This study might contribute to the rational development of V-based cathode materials for high-performance AZIBs and provide reliable insights into the reaction mechanism.

Covalent triazine frameworks (CTFs), as a burgeoning type of porous organic material, have attracted increasing attention in a lot of research fields, including gas separation, heterogeneous catalysis, etc. In particular, stemming from their heteroatom effect (HAE), incorporated with the merits of π-conjugated frameworks, electron-rich triazine units and extraordinary chemical stability, they exhibit prospective potential applications in chemical sensing. In this paper, a triazine-based conjugated porous organic polymer (DPA-CTF) containing anthracene units was used to study the sensing effects on nitroaromatic compounds and metal ions. Intriguingly, DPA-CTF showed sensitive detection performance towards nitroaromatic explosives, especially p-nitroaniline (p-NA). Besides, it also exhibited high sensitivity toward Fe3+ ions compared to other metal ions. A series of characterization studies and computational simulations were used to explain the mechanism of the luminescence quenching effect. These results manifest that the new synthesized CTF is a promising candidate as a chemical sensor for p-NA and Fe3+ ions.

A novel core-substituted naphthalenediimide derivative (DPyNDI-TPA) capped with electroactive triphenylamine was employed as an electroactive precursor to prepare p(DPyNDI-TPA) polymer films through in-situ electropolymerization on FTO substrates. In contrast to the non-core-substituted NDI-TPA, the introduction of pyrrolidine groups endows p(DPyNDI-TPA) films a distinct morphology and a capability of ionization. Under an electric field, the pyrrolidine group could release an electron and combined with counterions in electrolyte solution. Moreover, compared to p(NDI-TPA) films, the wrapped counter anions in p(DPyNDI-TPA) films could serve as balancing charges in electrochromic processes, which render the film a much better electrochromic performance (e.g., switching stability, coloring-bleaching speed and coloration efficiency). This meaningful design provides new conceptions for the design of organic electrochromic materials and shows great prospect in optoelectrical materials.

Two-dimensional (2D) transition metal chalcogenides (TMDs) are regarded as promising materials for micro-optoelectronic devices and next-generation logic devices due to their novel optoelectronic properties, such as strong excitonic effects, tunable direct bandgap from visible to near-infrared regions, valley pseudospin degree of freedom, and so on. Recently, triggered by the growing demand to optimize the performance of TMDs devices, external field regulation engineering has attracted great attention. The goal of this operation is to exploit the external fields to control exciton dynamics in 2D TMDs, including exciton formation and relaxation, and to finally achieve high-performance 2D TMDs devices. Although the regulation strategies of exciton dynamics in 2D TMDs have been well explored, the underlying mechanisms of different regulation strategies need to be further understood due to the complex many-body interactions in exciton dynamics. Here, we first give a brief summary of the fundamental processes of exciton dynamics in 2D TMDs and then summarize the main field-regulation strategies. Particular emphasis is placed on discussing the underlying mechanisms of how different field-regulation strategies control varied fundamental processes. A deep understanding of field regulation provides direct guidelines for the integrated design of 2D TMDs devices in the future.

Covalent organic frameworks (COFs) represent an emerging class of two- or three-dimensional crystalline porous materials with delicate control over topology, composition, and porosity. Here, we develop a new COF made up of 1,3,6,8-tetrakis(p-formylphenyl)pyrene (TFPPy) and 4,4'-diaminobenzophenone (DABP) that exhibits a rare one-dimensional (1D) structure. The resulting frameworks possess good crystallinity, comparatively high Brunauer-Emmett-Teller (BET) surface area (426 m2/g), and good thermal stability (360 °C). Impressively, this 1D COF shows strong fluorescence and can be used as an excellent H+ sensor in an acidic aqueous solution.

In the wake of the considerable investigation of two-dimensional (2D) materials, van der Waals (vdW) heterostructures based on atomically thin 2D materials show large potential for functional elect...

Directly growing nickel/cobalt-based cathode materials on current collectors as binder-free electrodes for rechargeable aqueous nickel/cobalt-Zn-based (NiCo//Zn) batteries have attracted tremendous attentions. However, most of the present binder-free cathodes suffer from low areal capacity and energy density, which severely restrict their practical applications. Herein, we demonstrate an efficient metal-organic framework (MOF)-involved strategy to rationally integration of the active NiCo2O4, CoMoO4 and Co3O4 cathode materials into one hierarchical arrayed structure that uniformly grown on nickel foam (NF) substrate (denoted as NF–NCO@CMO@CO) with a high mass loading of 9.6 ​mg ​cm−2. Such electrode design possesses favorable merits in the aspects of high electrical conductivity, robust arrayed architectures, abundant electrochemical active sites, rich redox reactions, facile ion diffusion and components’ synergetic effect. As a result, the aqueous NiCo//Zn battery based on NF–NCO@CMO@CO binder-free cathode exhibits an ultrahigh areal capacity of 2.51 ​mAh cm−2 at a current density of 2 ​mA ​cm−2, as well as good rate capability and long-term cycling stability. Impressively, the aqueous NF–NCO@CMO@CO//Zn battery shows a maximum areal energy density of 4.09 ​mWh cm−2 (corresponding to 424.5 ​Wh kg−1), which is superior to most of the previously reported aqueous NiCo//Zn batteries. Electrode reaction kinetics analysis reveals that both capacitive and diffusion-controlled behaviors are involved during the charge storage processes. Moreover, a quasi-solid-state NF–NCO@CMO@CO//Zn battery is also assembled by replacing the liquid electrolyte with gel electrolyte, suggesting the potential for practical applications. This work might shed light on the rational construction of advanced binder-free cathodes for high-performance aqueous NiCo//Zn batteries.

We studied the effect of silicon doping on the structure and crystallization behavior of 50V2O5-50TeO2 (mol%) (VT) glass by performing solid-state nuclear magnetic resonance (NMR), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and differential scanning calorimetry (DSC). We observed two interesting phenomena. First, when the mixture of glass and Si is heated in argon to 560 K (1.1Tg), Si starts to react with VT glass and is oxidized to amorphous silica, being confirmed by NMR and FTIR. Second, Si suppresses the formation of the Te2V2O9 phase in VT glass during heating process up to 650 K (about 1.3Tg), whereas it leads to the formation of the new crystalline phase TeVO4 during heating to 725 K (1.4Tg). We discuss the origin of these two phenomena by considering the changes both in glass structure and in the redox reaction.

One-dimensional bunched nanostructures have attracted particular research interest for their applications in energy-relate fields. However, developing a reasonable strategy to realize such unique s...

Traditional slurry-based electrodes consist of heavy current collectors and electroactive materials with a low weight percentage, which inevitably increase the total weight and cost of lithium-ion batteries (LIBs). Consequently, the development of low-cost, lightweight, flexible and binder-free electrodes for LIBs is highly desirable but also greatly challenging. In this work, we report the synthesis of small ZnO nanoparticles uniformly embedded in N-doped carbon (NC) nanoplate arrays (NPAs) tightly grown on a N-doped carbon paper (NCP) substrate (ZnO/NC NPAs@NCP) through a facile metal-organic framework-engaged strategy. This electrode design not only avoids the utilisation of insulating polymer binders but also offers other advantages, including large electrode/electrolyte contact areas, abundant electroactive sites, good wettability of the electrolyte, fast electron/ion transport and efficient volume accommodation. Notably, the freestanding ZnO/NC NPAs@NCP electrode displays a high reversible capacity of 610 mA h g−1 (based on the mass of entire electrode) at a current density of 100 mA g−1 for 50 cycles and excellent long-term cycling stability (363 mA h g−1 at 500 mA g−1 for 200 cycles). Furthermore, a full cell employing ZnO/NC NPAs@NCP as the anode and commercial LiFePO4 as the cathode is constructed, indicating the feasibility for practical application. Moreover, an analysis of the electrode kinetics confirms the favourable lithium-ion storage kinetics within the ZnO/NC NPAs@NCP electrode. The present work could provide a new approach to develop low-cost, lightweight and flexible electrodes for advanced energy storage.

The development of hollow structures with structural and composition complexity are highly attractive in the field of energy storage. In the present work, we demonstrate the rational construction of unique heterostructured core-shell Bi2S3@Co9S8 complex hollow particles (CHPs) through a facile metal-organic framework (MOF)-engaged strategy, in which the Bi2S3 spheres are well confined in the Co9S8 multi-cavity hollow shells. Benefiting from the specific structural and composition advantages, the core-shell Bi2S3@Co9S8 CHPs exhibit remarkable Li- and Na-ion storage performance in the aspects of high reversible capacity, excellent rate performance and long-term cycling stability. Electrochemical analyses reveal fast reaction kinetics in the core-shell Bi2S3@Co9S8 CHPs. Meanwhile, a Bi2S3@Co9S8//LiFePO4 full cell is successfully fabricated to evaluate their potential for real applications. In addition, the possible reaction mechanisms of the core-shell Bi2S3@Co9S8 CHPs for both Li- and Na-ion storage have been investigated via ex situ X-ray diffraction technique. Furthermore, density functional theoretical calculations confirm the heterostructure in the Bi2S3@Co9S8 CHPs can enhance the electrical conductivity and reaction kinetics. This work may offer new opportunities for integration of two active anode materials with high capacity and electrochemical activity into one heterostructured complex hollow structure.

A major impediment of the incorporation of extra functional groups on skeletons of covalent organic frameworks (COFs) is the long-ordered microporosity over their networks. This problem has delayed the practical applications of these highly porous materials for chemical sensing, CO2 capture, and heterogeneous catalysis. In this work, we demonstrated a facile method named the nonstoichiometric synthon strategy to introduce functional groups onto the network of the COFs for further metallic nanoparticle confinement. By simply adjusting the ratio of primitive synthons, we can deliberately decorate the interior pores of the resultant COF materials with amine groups from the excess synthon fragments, while maintaining the structure of the parent COF. Benefiting from the excess dangling amine groups on the network, these COFs are readily available as catalytic support for the confinement of ultrasmall metallic Pd nanoclusters and further used for the benzyl alcohol oxidation reaction.

Manganese-based oxides with high capacity and moderate operation voltage have been extensively studied as promising cathode materials for aqueous zinc ion batteries (ZIBs). However, the inherent poor electrical conductivity, sluggish reaction kinetics, huge volume expansion and dissolution of manganese species in electrolyte greatly restrict their practical applications. Herein, ultrasmall ZnMn2O4 nanodots uniformly anchored on reduced graphene oxide with strong interfacial interaction (ZnMn2O4 NDs/rGO composite) is synthesized. Compared with the pure ZnMn2O4 microspheres, the ZnMn2O4 NDs/rGO composite displays a much higher discharge capacity of 207.6 mA h g−1 at a current density of 0.2 A g−1, as well as better rate capability and long-term cycling stability. Impressively, the aqueous Zn//ZnMn2O4 NDs/rGO battery exhibits a high energy density of 266 W h kg−1 at a power density of 137 W kg−1, indicating great potential for practical applications. The excellent performance could be attributed to the abundant active sites, shortened ion diffusion pathway, improved electrical conductivity and good structure stability. Furthermore, electrochemical analyses reveal that favorable reaction kinetics towards efficient zinc ion storage is achieved in the composite. The present work might shed light on the rational design and synthesis of advanced strongly coupled graphene based composites as cathode materials for aqueous ZIBs.

Here we present the design and synthesis of a new robust microporous organic polymer (TPBP) decorated with phenazine groups which endowed reversibly redox-active properties. The obtained TPBP possesses relatively high surface area (359 m2/g) and good thermal stability. TPBP exhibits excellent catalytic capability for the oxidative homocoupling of amines with high activity and selectivity toward target products. Besides, this metal-free catalyst demonstrated excellent recyclability after 6 cycles under the investigated conditions. By means of EPR and UV-vis spectroscopy, a plausible mechanism of the amine oxidative coupling reaction was deduced via a single electron transfer from TPBP radical cations to amine substrates.

Mixed transition metal sulfides (TMSs) with hollow and complex hollow structures have attracted intensive attentions as high-performance cathode materials for rechargeable alkaline batteries. However, these powder-based electrode materials should be further mixed with insulative polymer binders and suffered from complicate electrode fabrication process. Herein, for the first time, we demonstrate the delicate design and synthesis of the sugar gourd-like multi-component yolk-shell Ni–Mo–Co–S nanocage arrays (NCAs) on Ni foam (NF) through a facile metal-organic framework (MOF)-engaged strategy. The synthetic process includes the growth of Co-based zeolitic imidazolate framework (ZIF-67) polyhedra onto the NiMoO4·xH2O nanorod arrays (NRAs) at room temperature and followed by a sufficient sulfidation reaction. Benefiting from the intriguing structural and compositional advantages, the yolk-shell Ni–Mo–Co–S NCAs/NF binder-free electrode exhibits an extremely high areal capacity of 1.96 mAh cm−2 at a current density of 5 mA cm−2 and excellent cycling stability. The electrode kinetics analysis confirms the diffusion-controlled battery-type behavior of the yolk-shell Ni–Mo–Co–S NCAs/NF electrode. The corresponding full cell delivers an high energy density of 92.6 Wh kg−1 at the power density of 1029.1 W kg−1 with the yolk-shell Ni–Mo–Co–S NCAs/NF as cathode electrode and Bi2O3 as anode electrode, indicating the potential for real applications. This work would make contribution to the realization of directly growing multi-component hollow and complex hollow structures on conductive substrate for high-performance electrochemical energy storage.

When designing Fe–N–C electrocatalysts as platinum group metal-free catalysts for the oxygen reduction reaction, pore engineering is crucial, in addition to creating active sites. In this study, g-C3N4 was added during the pyrolysis process of polyaniline and cyanamide, increasing the density of active sites and pore volume of the final product. The uniform distribution of atoms and relatively high ratio of pores resulted in the unprecedented electroreduction of oxygen through a 4e− pathway in acidic and alkaline media. In 0.1 M KOH solution, the half-wave potential of the modified catalyst (E1/2 = 0.912 V vs. RHE) was 50 mV more positive than that of a commercial 20% Pt/C catalyst. The durability of the catalyst was also better than that of the commercial Pt/C catalyst in acidic and alkaline media.

The development of electrode materials with the capability of balancing kinetics and capacity between a battery-type anode and capacitor-type cathode is still a grand challenge for potassium-ion hybrid capacitors (PIHCs). Herein, we report the design and synthesis of phosphorus/nitrogen co-doped hierarchical porous carbon nanofibers (PN-HPCNFs) that feature desirable one dimensional (1D) structure and favorable electrochemical properties for PIHC application. We demonstrated that the as-prepared PN-HPCNFs presented a highly attractive performance in terms of capacity or capacitance and durability as both the battery-type anode and capacitor-type cathode of PIHCs, which endows it with great potential for practical application in full PIHCs by delivering a high energy density of 191 W h kg−1 and a high power output of 7560 W kg−1 as well as an ultralong lifespan (82.3% capacity retention after 8000 cycles). Systematic characterization analysis and first-principle calculations demonstrated that the hierarchical pores in the 1D structure, heteroatom P/N co-doping, and enlarged interlayer graphite spacing in the APN-HPCNF contributed synergistically to the outstanding electrochemical performance of PIHCs.

Aggregation-induced emission (AIE) properties have been widely investigated not only because they thoroughly circumvent the notorious aggregation-caused quenching effect encountered in conventional fluorophores but also due to their promising applications in organic light-emitting diodes, fluorescent sensors and bioimaging. In this work, we reported a study of the molecular packing and luminescence properties of AIE active positional isomers (m-BPCDM and p-BPCDM) with carbazole and dicyanovinyl groups. The compound m-BPCDM based on meta-substitution showed more evident AIE processes than the compound p-BPCDM based on para-substitution, which can be attributed to the strong π–π stacking effect brought by the spatial structure of p-BPCDM. Moreover, the two positional isomers also exhibited distinct mechanochromic luminescence properties.

A water-stable and pH-independent sensor for qualitative and quantitative detection of nicotine in urine solution and living cell was successfully developed. This material, named MB@UiO-66-NH2, can be synthesized by encapsulating methylene blue (MB) with a well-known metal-organic framework (MOF) UiO-66-NH2 through a simple impregnation method. The fluorescence intensity of the system was significantly enhanced when a certain amount of nicotine was added. In the meanwhile, MB is reduced by reductive nicotine to form leucomethylene blue (LB). The proposed sensor displayed excellent selectivity and sensitivity toward nicotine with limit of detection (LOD) of 0.98 μM, which is comparable or even better than that of the electrochemistry detecting methods for nicotine. The obvious enhancement and blue shift of the emission arise from the photoinduced electron transfer (PET) from LB to the UiO-66-NH2. The photophysical properties and the sensing applications of MB@UiO-66-NH2 suggest that this composite can be acted as a sensitive, selective, recyclable, and fluorogenic sensor for nicotine determination in urine solution and living cell.

Developing facile strategies to synthesize transition metal oxides and nitrogen-doped carbon (NC) hybrid materials is important for lithium-ion batteries (LIBs) but also challenging. Herein, unique one-dimensional multicomponent MoO2@CoO-CoMoO4-NC hybrid nanorods have been successfully synthesized. Benefiting from the unique morphology, structure and components, the MoO2@CoO-CoMoO4-NC hybrid nanorods exhibit a high reversible discharge capacity of 1164.0 mA h g−1 at 200 mA g−1 for 80 cycles, good rate performance (394.5 mA h g−1 at 4000 mA g−1) and cycling stability (688.8 mA h g−1 at 1000 mA g−1 for 350 cycles). It is believed that the MoO2@CoO-CoMoO4-NC hybrid nanorods could be very promising anode materials for LIBs.