Search

Antibacterial hydrogels, as novel antibacterial materials with three-dimensional porous network structures, have inherent or exogenous antibacterial activity, appropriate mechanical properties, and high biocompatibility for local use, and these hydrogels synthesized through appropriate selection of gel components, crosslinkers, and functional molecules or groups can be used for controlled release of drugs, stimulus-responsive activation, synergistic antibacterial therapy, and so forth. With the progress of the functionalized construction and the performance regulation technology of hydrogels, antibacterial hydrogels have been widely used in biomedical-related fields for drug delivery, cell encapsulation, wound healing, bone repair, tissue engineering, antibacterial coating of medical devices, sensing and health monitoring. Here, we introduce the different types of antibacterial hydrogels from their components, preparation processes, and antibacterial mechanisms to their translational applications in the biomedical field. In addition, the current situation and bottleneck for the application of antibacterial hydrogels in the medical field are discussed, which is beneficial for indicating the future research directions of antibacterial hydrogels in the biomedical field. [ABSTRACT FROM AUTHOR]

The development of high-performance electrode materials and the rational design of asymmetric structures are the two main keys to fabricating micro-supercapacitors (MSCs) with high energy density. Transition metal compounds, especially nickel–cobalt phosphides and hydroxides, are promising electrode materials with excellent pseudo-capacitance. However, they are rarely used in fabricating asymmetric MSCs (AMSCs) due to the limitations of the preparation method. In this work, we constructed hierarchical Ni–Co–P@LDH nanocomposites with outstanding mass specific capacitance (1980 F g−1 at 1 A g−1) via a multi-step electrodeposition method, which is employed with FeOOH to fabricate an interdigital AMSC device (Ni–Co–P@LDHs//PVA–KOH//FeOOH). The as-prepared device exhibits a high working voltage (1.4 V), a large specific capacitance (24.0 mF cm−2 at 0.14 mA cm−2), a high energy density (6.54 μW h cm−2 at a power density of 100 μW cm−2) and good cycling stability (86.5% of capacitance retention after 5000 cycles). This work may provide novel methods for the synthesis of high-performance nickel–cobalt composite materials and their potential applications in interdigital AMSC devices. [ABSTRACT FROM AUTHOR]

Transition metals are commonly employed as catalysts for the oxidation of cyclohexane. However, the harsh reaction conditions and the low efficiency hinder their further application. In this work, to further improve the reaction efficiency, transition metal oxide (CoO and MnO)/graphene composites are fabricated as heterogeneous catalysts for the oxidation of cyclohexane. Among the as synthesized catalysts, CoO/graphene (CoO/G) exhibits the best catalytic efficiency. The structure characterization illustrated that the transition metal oxides are well anchored on the graphene sheets, thus leading to the fine distribution of the catalyst. To demonstrate the synergistic catalytic activity of CoO and graphene in the oxidation process of cyclohexane, CoO loaded on other supports, pure CoO and pure graphene were also adopted as the catalyst for the oxidation reaction under the same conditions. The results show that CoO or graphene solely exhibits relatively low catalytic activity, but their hybrid efficiently improves the conversion and selectivity. By optimizing the experimental conditions, 32.4% conversion of cyclohexane and 75.4% selectivity to K/A oil could be achieved. [ABSTRACT FROM AUTHOR]

Herein, we have managed to conceive and fabricate a core–shell structured triangle-like array, where a selenylation-treated MOF array was grown in situ on a conducting substrate as a highly conductive framework to support a high loading of Mo-doped nickel–cobalt LDH nanoflakes. This hierarchical electrode integrates the advantages of a defect-rich electronic state, large active area and rich reaction sites, delivering a high areal capacity of 5.16 C cm−2 and a high rate capability. [ABSTRACT FROM AUTHOR]

Transition metal phosphides (TMPs) represent an important class of compounds with metalloid characteristics and good electrical conductivity, which are of great benefit to enhance electrochemical performances. Thus it is important to clarify the correlation between the electrochemical properties and the phosphating degree of the precursor. Herein, we report a superior electrode for battery-like capacitors based on NiCo2O4/NiCoP hetero-structure nanoflake-nanowire arrays grown on nickel foams using a one-pot facile hydrothermal approach and a controllable phosphorization treatment method. The Ni–Co precursor nanoflake-nanowire array based electrode treated with 500 mg NaH2PO2 shows significantly improved electrochemical performances with an ultrahigh specific capacitance of 2288.8 F g−1 and 1644 F g−1 at a current density of 1 A g−1 and 20 A g−1, respectively. The electrode also shows superior cycling stability. In addition, the NiCo2O4/NiCoP//AC device exhibits a relatively high energy density of 35.5 W h kg−1 at 750.4 W kg−1. The results suggest that this NiCo2O4/NiCoP nanoflake-nanowire array is a promising electrode material for high performance hybrid supercapacitor applications. [ABSTRACT FROM AUTHOR]

Homogeneous SnO2 hollow spheres have been synthesized through a hydrothermal method without a template, followed by in situ polymerization of PANI. The resulting SnO2 hollow spheres were uniformly deposited onto the surface or embedded into the PANI nanofibers to form a SnO2–PANI network structure. As electrode materials, the SnO2–PANI composites exhibit greatly enhanced specific capacitance (477 F g−1 at a current density of 1 A g−1) and superior cycling performance (no capacitance loss after 3000 galvanostatic charge–discharge cycles). These intriguing features are attributed to the interaction between the SnO2 hollow spheres and PANI network. On the one hand, the SnO2 spheres not only provide larger area for electrochemical reaction but also release volume expansion during the charge–discharge process. On the other hand, the conducting PANI improves electrical conductivity and maintains mechanical integrity of the composites as well. [ABSTRACT FROM AUTHOR]

In this study, ternary composites of reduced graphene oxide/molybdenum disulfide/polyaniline (rGEO/MoS2/PANI) were prepared via a two-stage facile synthesis including a hydrothermal reaction and polymerization at room temperature which makes the materials much easier for industrialization. The doping of reduced graphene oxide (rGEO) decreases the aggregation of MoS2 and enhances the electronic conductivities of MoS2, thus exhibiting better capacitance properties (531 F g−1 at 1 A g−1) and cycling stabilities (86.7% retained capacitance over 3000 cycles at 1 A g−1) of ternary composites than a uniform material (MoS2) or binary materials (MoS2/PANI). The combined effects between the three components make the composites obtain both pseudocapacitance and double-layer capacitance, which can be used to explain the improvement of electrochemical performances. [ABSTRACT FROM AUTHOR]

To achieve high piezoelectric activity and a wide sintering temperature range, the ceramic system concerning (1 −x)(K0.48Na0.52)(Nb0.96Sb0.04)O3–x[Bi0.5(Na0.7Ag0.3)0.5]0.90 Zn0.10ZrO3 was designed, and the rhombohedral–tetragonal (R–T) phase boundary can drive a high d33. Phase transition characteristics as well as their effects on the electrical properties were investigated systematically. The R–T coexistence phase boundary (0.04 ≤x≤ 0.05) can be driven via modification with BNAZZ, and has been confirmed by XRD and temperature-dependent dielectric constants as well as Raman analysis, and the ceramics possess enhanced piezoelectric properties (d33∼ 425 pC N−1 and kp∼ 0.43) and a high unipolar strain (∼0.3%). In addition, a wide sintering temperature range of 1050–1080 °C can warrant a large d33 of 400–430 pC N−1, which can benefit practical applications. As a result, the addition of BNAZZ is an effective method to improve the electrical properties (piezoelectricity and strain) and sintering behavior of potassium-sodium niobate ceramics. [ABSTRACT FROM AUTHOR]

The development of high-performance electrode materials and the rational design of asymmetric structures are the two main keys to fabricating micro-supercapacitors (MSCs) with high energy density. Transition metal compounds, especially nickel-cobalt phosphides and hydroxides, are promising electrode materials with excellent pseudo-capacitance. However, they are rarely used in fabricating asymmetric MSCs (AMSCs) due to the limitations of the preparation method. In this work, we constructed hierarchical Ni-Co-P@LDH nanocomposites with outstanding mass specific capacitance (1980 F g -1 at 1 A g -1 ) via a multi-step electrodeposition method, which is employed with FeOOH to fabricate an interdigital AMSC device (Ni-Co-P@LDHs//PVA-KOH//FeOOH). The as-prepared device exhibits a high working voltage (1.4 V), a large specific capacitance (24.0 mF cm -2 at 0.14 mA cm -2 ), a high energy density (6.54 μW h cm -2 at a power density of 100 μW cm -2 ) and good cycling stability (86.5% of capacitance retention after 5000 cycles). This work may provide novel methods for the synthesis of high-performance nickel-cobalt composite materials and their potential applications in interdigital AMSC devices.

Transition metal phosphides (TMPs) represent an important class of compounds with metalloid characteristics and good electrical conductivity, which are of great benefit to enhance electrochemical performances. Thus it is important to clarify the correlation between the electrochemical properties and the phosphating degree of the precursor. Herein, we report a superior electrode for battery-like capacitors based on NiCo2O4/NiCoP hetero-structure nanoflake-nanowire arrays grown on nickel foams using a one-pot facile hydrothermal approach and a controllable phosphorization treatment method. The Ni-Co precursor nanoflake-nanowire array based electrode treated with 500 mg NaH2PO2 shows significantly improved electrochemical performances with an ultrahigh specific capacitance of 2288.8 F g-1 and 1644 F g-1 at a current density of 1 A g-1 and 20 A g-1, respectively. The electrode also shows superior cycling stability. In addition, the NiCo2O4/NiCoP//AC device exhibits a relatively high energy density of 35.5 W h kg-1 at 750.4 W kg-1. The results suggest that this NiCo2O4/NiCoP nanoflake-nanowire array is a promising electrode material for high performance hybrid supercapacitor applications.

Homogeneous SnO 2 hollow spheres have been synthesized through a hydrothermal method without a template, followed by in situ polymerization of PANI. The resulting SnO 2 hollow spheres were uniformly deposited onto the surface or embedded into the PANI nanofibers to form a SnO 2 -PANI network structure. As electrode materials, the SnO 2 -PANI composites exhibit greatly enhanced specific capacitance (477 F g -1 at a current density of 1 A g -1 ) and superior cycling performance (no capacitance loss after 3000 galvanostatic charge-discharge cycles). These intriguing features are attributed to the interaction between the SnO 2 hollow spheres and PANI network. On the one hand, the SnO 2 spheres not only provide larger area for electrochemical reaction but also release volume expansion during the charge-discharge process. On the other hand, the conducting PANI improves electrical conductivity and maintains mechanical integrity of the composites as well.

In this study, ternary composites of reduced graphene oxide/molybdenum disulfide/polyaniline (rGEO/MoS 2 /PANI) were prepared via a two-stage facile synthesis including a hydrothermal reaction and polymerization at room temperature which makes the materials much easier for industrialization. The doping of reduced graphene oxide (rGEO) decreases the aggregation of MoS 2 and enhances the electronic conductivities of MoS 2 , thus exhibiting better capacitance properties (531 F g -1 at 1 A g -1 ) and cycling stabilities (86.7% retained capacitance over 3000 cycles at 1 A g -1 ) of ternary composites than a uniform material (MoS 2 ) or binary materials (MoS 2 /PANI). The combined effects between the three components make the composites obtain both pseudocapacitance and double-layer capacitance, which can be used to explain the improvement of electrochemical performances.

To achieve high piezoelectric activity and a wide sintering temperature range, the ceramic system concerning (1 - x)(K(0.48)Na(0.52))(Nb(0.96)Sb(0.04))O(3)-x[Bi(0.5)(Na(0.7)Ag(0.3))(0.5)](0.90) Zn(0.10)ZrO(3) was designed, and the rhombohedral-tetragonal (R-T) phase boundary can drive a high d(33). Phase transition characteristics as well as their effects on the electrical properties were investigated systematically. The R-T coexistence phase boundary (0.04 ≤ x ≤ 0.05) can be driven via modification with BNAZZ, and has been confirmed by XRD and temperature-dependent dielectric constants as well as Raman analysis, and the ceramics possess enhanced piezoelectric properties (d(33) ∼ 425 pC N(-1) and k(p) ∼ 0.43) and a high unipolar strain (∼0.3%). In addition, a wide sintering temperature range of 1050-1080 °C can warrant a large d(33) of 400-430 pC N(-1), which can benefit practical applications. As a result, the addition of BNAZZ is an effective method to improve the electrical properties (piezoelectricity and strain) and sintering behavior of potassium-sodium niobate ceramics.