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The cycloaddition of carbon dioxide to epoxide (CCE) reaction stands out as one of the few feasible chemical processes for catalytically fixing CO2. Traditionally, halide anions were frequently used as cocatalysts for catalysing the CCE reaction owing to their excellent nucleophilic and leaving abilities. However, halides are known for their corrosive effects on process reactors, and their treatment is challenging. Consequently, there is a substantial increase in the demand for halide-free catalysis in the CCE reaction. Herein, a series of bifunctional catalysts were designed for CCE reactions. The reactions were assessed under conditions of 120 °C and 1 MPa employing a catalyst loading of 0.5 mol% over 24 hours. The dual activation mechanism of the catalyst was confirmed through NMR titration and control experiments. As a bifunctional catalyst, the ion pair polarized the oxygen atom of epoxide via H-bonding with N+–H while the phenolate anion activated carbon dioxide simultaneously. This study introduces a pyridinium base binary organocatalyst as a halide-free hydrogen bond donor (HBD) anion organocatalyst with broad applicability for CO2 utilization. [ABSTRACT FROM AUTHOR]

Zwitterionic catalysis is powerful in simultaneously activating electrophiles and nucleophiles in organic transformations; however, its potential in polymerizations remains untapped. Herein, a zwitterionic catalytic model for ring-opening polymerization (ROP) is introduced and a series quaternary ammonium carboxylate zwitterionic catalysts have been designed and evaluated in the ROPs of cyclic esters. Among the zwitterionic catalysts, L -carnitine, a commercially available and inexpensive natural product, showed the optimal catalytic performance. ROPs of L -lactide (L -LA), trimethylene carbonate, δ-valerolactone and ε-caprolactone were successful. PLLA was prepared with controlled molecular weight (1.4 to 21.2 kg mol−1) and narrow dispersion (Đ 1.02 to 1.21). The zwitterionic catalytic mechanism is proposed where quaternary ammonium and hydroxyl cooperatively activated the carbonyl of monomers, while the carboxylic anion activated the chain-end/initiator. NMR titrations validated the bifunctional activation mechanism. Organocatalysts of zwitterionic nature provide a new design tool for wider scope investigation of catalytic polymerizations. [ABSTRACT FROM AUTHOR]

Inspired by morphological control and element doping, nanorod NFS-X ((NiFe)9S8 with different Ni : Fe molar ratios) was synthesized by a hydrothermal method. In this work, uniform and dense NF-X (X = 0, 1, 3, 5, 7, 9 and 10) materials were prepared on NiFe foam, and as a precursor, the nanorod was formed in situ by sulfurization in ethanol. NFS-X (X = 0, 1, 3, 5, 7, 9 and 10) with nanorod morphology was successfully obtained by controlling the Ni and Fe ratio. The optimized NFS-3 has a unique nanorod structure, which provides abundant electrochemical active sites and sufficient electron and electrolyte migration paths for fast and deep Faraday reactions. A specific capacitance of 3620 mF cm−2 at 2 mA cm−2 was obtained with significant cycling performance (83.3% retention after 7000 cycles at 20 mA cm−2). Furthermore, asymmetric supercapacitor CNHC//NFS-3 was prepared by using NFS-3 nanorods as a cathode and double-shell layer Co/Ni-based alkaline carbonate (CNHC) as an anode. The device presents an excellent energy density of 68.9 Wh kg−1 at a power density of 0.74 kW kg−1 while driving a small fan for operation, exhibiting potential for practical applications. [ABSTRACT FROM AUTHOR]

Crystalline selenium, characterized by higher electronic conductivity and volumetric capacity, represents one of the most promising cathode materials for next-generation battery technologies. However, the notorious lithium polyselenide shuttle effects yield formidable challenges, causing overcharge problems and unsatisfactory cycle performances. In this work, a nanosheet on nanorod WSe2/WO2 heterostructure was firstly developed as a proof of concept to immobilize and catalyze the soluble lithium polyselenides species. Through an in situ selenization process, the W5O14–ethylenediamine nanorod precursor was transformed to the WSe2/WO2 heterostructure, which was composed of long WO2 nanorods and WSe2 nanosheets. A combination of visual adsorption/permeation experiments, Li2Se electrochemical deposition tests, and theoretical calculations unraveled the strong chemical anchoring and efficient re-utilization toward soluble Li2Se6 and Li2Se4 species on the as-designed WSe2/WO2 heterostructure, which can originate from the bridge-shaped interfacial bonding structure. As anticipated, Li–Se batteries based on WSe2/WO2 heterostructure-modified separator exhibited dramatically improved overcharge property (overcharge capacity is 28.3 mA h g−1, only 73.7% of that with pristine PP separator) and cycle performances (about 1.58 times higher than that with pristine PP separator). [ABSTRACT FROM AUTHOR]

Tremendous challenges still lie ahead in synergistically improving the pH-universal HER performance of noble metal-free electrocatalysts by multiple modification strategies. Herein, In2S3@Cu2S nanorod heterostructure arrays were in situ grown on a copper foam (In2S3@Cu2S NAs/CF) through the traditional solvothermal method, followed by calcination, hence constructing an efficient electrocatalyst for pH-universal HER. The optimal In2S3@Cu2S NAs/CF-2 electrocatalyst requires overpotentials of only 42 mV, 78 mV, and 61 mV to drive a current density of 10 mA cm−2 in acidic, neutral, and alkaline media, respectively. Furthermore, In2S3@Cu2S NAs/CF-2 also exhibits salient stability after 20 000 cycles and 150 h long-term use. The outstanding electrocatalytic performance is mainly attributed to the formation of a strong built-in electric field on the heterostructure interface, the increase in the accessible active sites, optimization of the electronic structure derived from abundant S vacancies, as well as the enhancement of the electrochemically active area owing to the unique vertically grown nanoarray structure. This work will pave a new avenue toward multiple modification strategies to synergistically improve electrocatalytic hydrogen production in a wide pH range. [ABSTRACT FROM AUTHOR]

As a practical approach for hydrogen generation, electrolysis water-splitting, particularly in seawater, is considered an attractive technique. Herein, an Fe–Ni based compound on a NiFe foam (Fe–Ni–O–N) is in situ engineered via ambient corrosive engineering, following low-temperature nitridation. The as-prepared Fe–Ni–O–N presents a flower-like morphology composed of nanosheets with abundant active sites, large surface area, and rich channels. Moreover, the superhydrophobic surface and porous matrix favor accelerating the mass and charge transfer. Benefiting from the above merits, 1.49 and 1.51 V are required for Fe–Ni–O–N electrocatalyst for OER with low potentials to reach 500 mA cm−2 in 1 M KOH fresh water and seawater. Moreover, to deliver 500 mA cm−2, low cell voltages of 1.87 V and 1.90 V are required in 1 M KOH freshwater-splitting and seawater-splitting. For industrial applications, the assembled electrolyzer exhibits remarkable catalytic performances and stabilities under large current densities in freshwater and seawater (60 °C, 6 M KOH). [ABSTRACT FROM AUTHOR]

The electrochemical oxidation of ethylene glycol (EG), which is favorable for replacing the sluggish oxygen evolution reaction (OER) in thermodynamics, realizes energy-saving hydrogen evolution and also produces high-value chemical products of glycolic acid. Under the guidance of this concept, PtRh nanowires with Rh atom modification (PtRh0.02@Rh NWs), which exhibited excellent properties during the hydrogen evolution reaction (HER) and ethylene glycol evolution reaction (EGOR), were designed and synthesized by controlling the reduction rate of metal precursor through a simple one-step solvothermal reduction. The interface strain effect produced by the metal co-doping effectively adjusted the electronic structure, contributing to introducing the heteroatom active center and inducing lattice strain, thereby achieving excellent electrocatalytic performance. The obtained PtRh0.02@Rh NWs exhibited excellent HER property with an extremely low overpotential of 30.6 and 45.8 mV, and Tafel slope of 39.1 and 39.5 mV dec−1 in alkaline water and seawater electrolytes, respectively, as well as outstanding EGOR properties with peak current density of 1.25 and 1.17 A mg−1, respectively. Additionally, the PtRh0.02@Rh NWs showed superior stability compared to that of commercial platinum black obtained from Johnson Matthey Corporation (JM-Pt black). When using PtRh0.02@Rh NWs as biofunctional materials for the HER in the cathode and the EGOR in the anode, a cell voltage of only 0.66 V for PtRh0.02@Rh NWs (HER)‖PtRh0.02@Rh NWs (EGOR) achieved a current density of 10 mA cm−2, which was much smaller than that of PtRh0.02@Rh NWs (HER)‖PtRh0.02@Rh NWs (OER) at 1.57 V. The results of electrochemical in situ Fourier transform infrared (FTIR) spectroscopy showed that the synthesized PtRh0.02@Rh NWs promoted the production of high-value glycolic acid when EG was dehydrogenated to form C2 intermediates. The Rh atoms modified on the surface of the Pt nanowires provided an effective strain effect to optimize the active sites, which creates a universal strategy for the design of highly efficient and durable bifunctional catalysts. [ABSTRACT FROM AUTHOR]

Exploring the integration regulation strategies to boost the electrocatalytic performance and elucidating the manipulation mechanism are critical for the hydrogen economy. Herein, heteroatom doping and heterojunction strategies were integrated to engineer a V-Ni3FeN/Ni@N-GTs bifunctional electrocatalyst, where the V-Ni3FeN/Ni heterojunction consisting of V doped Ni3FeN and Ni was anchored on N-doped graphene nanotubes (N-GTs). Benefiting from the modulation of the d-band center of hosts Ni and Fe by V doping and the regulation of local charge distribution induced by the V-Ni3FeN/Ni heterojunction, combined with the introduction of the conductive N-GTs skeleton, V-Ni3FeN/Ni@N-GTs delivers overpotentials of 66 and 252 mV at 10 mA cm−2 for the HER and OER, respectively. Besides, when it is used as a bifunctional electrocatalyst for overall water splitting, a low cell voltage of 1.55 V is needed to achieve a current density of 10 mA cm−2. This work provides new inspiration for developing other promising electrocatalysts based on the integration of various strategies. [ABSTRACT FROM AUTHOR]

Electrocatalytic hydrogen evolution reaction (HER), as a promising green and sustainable method for hydrogen production, has received widespread attention, and designing efficient and stable electrocatalysts is one of the keys to accelerating the development of the hydrogen economy. Herein, B and Ru co-doped iron hollow spheres (H-B/Ru-FeP) are synthesized by ambient boronation, low-temperature phosphorization and acid leaching processes. The hollow porous structure and doping strategy favor enhancing the electrocatalytic kinetics by exposing numerous active sites, building rich mass transport channels and providing efficient adsorption/desorption of reactant/intermediates. Then, the as-synthesized H-B/Ru-FeP exhibits excellent electrocatalytic performance toward HER with low overpotentials of 29 mV, 86 mV, and 110 mV, to drive the current density of 10 mA cm−2 in acidic, neutral and alkaline electrolytes, respectively. The electrolyzer is assembled with H-B/Ru-FeP as the cathode and NiFe foam as the anode, requiring a low cell voltage of 1.54 V to drive 10 mA cm−2. This work opens a novel approach to exploit hollow structures for energy conversion and storage applications. [ABSTRACT FROM AUTHOR]

Designing bifunctional electrocatalysts with high activity and durability for overall water splitting in acid electrolytes is still a huge challenge because their excellent activity is difficult to maintain. Herein, a method to stabilize the charge redistribution on catalysts by constructing Pt–RuO2@KB heterostructures with strong metal–support interactions is proposed first to achieve remarkable water splitting performance in acidic media. By performing X-ray photoelectron spectroscopy (XPS) before and after a 150 h long-time v–t test, it is found that the electron transfer from Pt to RuO2 could form a stable charge redistribution. Benefiting from the Pt–RuO2 heterostructures, the strong metal–support interaction (SMSI) between Pt–RuO2 and KB as well as the stable charge redistribution between Pt and RuO2, Pt–RuO2@KB exhibits ultrahigh intrinsic activity (the turnover frequency (TOF) value is 34.5 s−1 @ 300 mV for the oxygen evolution reaction (OER) and 20.2 s−1 @ 100 mV for the hydrogen evolution reaction (HER), respectively) and outstanding overall water splitting performance (only needs 1.54 V at a current density of 10 mA cm−2). Notably, Pt–RuO2@KB with the stable charge redistribution exhibits striking stability for overall water splitting; during a 150 h continuous v–t test, the voltage is maintained well without noticeable degradation in 0.1 M HClO4. Density functional theory (DFT) calculations verify that the charge redistribution between Pt and RuO2 can dramatically lower the water splitting barrier and raise the vacancy formation energy of atoms in the catalyst, which could effectively inhibit the dissolution of atoms in Pt–RuO2@KB in an acidic medium and achieve superior water electrolysis performance. [ABSTRACT FROM AUTHOR]

Developing advanced negative and positive electrode materials for asymmetric supercapacitors (ASCs) as electrochemical energy storage devices can enable the device to reach high energy/power densities resulting from the cooperative effect of the two electrodes. In this work, a nanochain-like hybrid nanostructured composite of MoO3 with rich oxygen vacancies (MoO3−x) in situ grown on N-doped graphene nanotubes (N-GNTs) is synthesized as the negative electrode for an ASC. It can deliver a large specific capacitance (591 F g−1 at 2 A g−1), as well as an outstanding rate capability. Simultaneously, N-GNTs@Na+-preinserted MnO2 (NaxMnO2) nanosheet arrays are fabricated as the positive electrode of the ASC, which can exhibit an enhanced specific capacitance of 429 F g−1 with a wide potential window of 0–1.2 V. When these two different electrodes are assembled in an ASC, a maximum energy density of 105 W h kg−1 at 2.2 kW kg−1, and an ultralong lifespan with 95.4% capacitance retention after 10 000 cycles are achieved, which are superior to those of the reported ASC devices to date. Density functional theory (DFT) calculations show that benefitting from the designed vacancy defects and unique N-GNT skeleton, the electronic structure and adsorption energy can be adjusted to greatly boost the electrical conductivity and ion adsorption efficiency and subsequently enhance the capacitive properties of the electrodes in the ASC. [ABSTRACT FROM AUTHOR]

Although water electrolysis provides a promising technology for global hydrogen economics, highly efficient electrocatalysts are required to boost the sluggish kinetics of both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) under neutral conditions. Herein, we synthesized novel polyethyleneimine (PEI) functionalized Echinops-like Rh porous nanostructures (Echinops-like Rh PNNSs) by a solvothermal method, which originated from the self-assembly of Rh two-dimensional (2D) sub-nanoflakes with 1.2 nm thickness. As a good electron donor, −NH2 on PEI could modulate the electronic structure of Echinops-like Rh PNNSs, reducing the adsorption energy of H2O on the surface of Echinops-like Rh PNNSs. Meanwhile, −NH2 groups could specifically enrich H2O molecules under neutral conditions, which facilitates water splitting. The as-synthesized Echinops-like Rh PNNSs exhibit high HER activity with ultralow overpotential, low Tafel slope, and excellent stability. Moreover, the Echinops-like Rh PNNSs also showed an enhanced OER activity than commercial RuO2 with a small overpotential of 79.5 mV at 10 mA cm−2 in neutral media. When using Echinops-like Rh PNNSs as both anode and cathode catalysts for overall seawater splitting, a cell voltage of only 1.61 V is needed for generating 10 mA cm−2 current density, greatly boosting the efficiency of seawater splitting. [ABSTRACT FROM AUTHOR]

A copper-catalyzed regioselective [3+2] annulation of malonate-tethered acyl oximes with isatins was developed, affording valuable 2,3-dihydrooxazole-spirooxindoles in moderate to good yields with excellent diastereoselectivity. The reaction sequence involves Cu(I) initiated N–O bond cleavage, 1,5-HAT and C–N bond formation. The protocol features mild reaction conditions and broad substrate scope. DFT calculations demonstrated that the [3+2] annulation pathway is more energetically favourable in both kinetics and thermodynamics. [ABSTRACT FROM AUTHOR]

MXenes refer to a family of 2D transition metal carbides/nitrides that are rich in chemistry. The first member of the family, Ti3C2Tx, was reported in 2011. Since then MXenes have opened up an exciting new field in 2D inorganic functional materials by virtue of their intrinsic electronic conductivity, superior hydrophilicity, rich surface chemistry and layered structure, as evidenced by the fact that the number of papers on MXenes has increased exponentially. The unique properties and ease of processing have positioned them as promising materials for a variety of applications including energy storage, especially for supercapacitors. In this review, we aim to summarize the current advances in MXene research on supercapacitors. We begin by reviewing various fabrication routes and their influence on the structure and surface chemistry of MXenes. The structure, properties, stability, and species of layered MXenes are then introduced. The focus then turns to the capacitive energy-storage mechanisms and the factors determining the electrochemical behavior and performance in supercapacitors. Besides, various types of MXene-based supercapacitors are summarized to highlight the significance of MXenes in constructing energy storage devices. Finally, challenges and prospects in this booming field are proposed to promote further development of MXenes in supercapacitors. [ABSTRACT FROM AUTHOR]

The intelligent construction of electrode nanostructures with unique morphologies is of admirable importance for increasing the energy storage capacity of highly efficient supercapacitor devices. In this study, the negative electrode material Bi2O3/Bi2Se3 nanoflower (Bi2O3/Bi2Se3 NFs) hybrid was first fabricated via a simple one-step solvothermal approach; due to the favorable conductivity of Bi2Se3, high theoretical capacity of Bi2O3 and their distinctive nanostructures, the achieved Bi2O3/Bi2Se3 NFs exhibited the maximum specific capacity of 132.7 mA h g−1 (∼531 F g−1) at 1 A g−1 and the superior rate capability of 113.8 mA h g−1 (∼455 F g−1) at 10 A g−1. Moreover, the positive electrode material NiCoSe2/Ni0.85Se nanoparticles (NiCoSe2/Ni0.85Se NPs) obtained by an electrodeposition method delivered the high specific capacity of 248.4 mA h g−1 (∼1788 F g−1) at 1 A g−1 as well as the appealing rate property of ∼84% capacity retention when the current density was increased by 100 times (i.e., 100 A g−1). More significantly, it was found that the assembled Bi2O3/Bi2Se3 NFs//NiCoSe2/Ni0.85Se NP asymmetric aqueous battery (AAB) device achieved the extraordinary energy density of 88.4 W h kg−1 at the power density of 2.4 kW kg−1 along with a durable lifespan (maintaining the capacity retention of up to 91.5% even after 10 000 cycles). Consequently, the design strategy and novel perspectives reported herein not only hold extensive promise for expanding the preparation techniques of morphology-controlled composites with robust electrochemical properties but also promote the practical applications of newly emerging metal selenides in next-generation aqueous batteries. [ABSTRACT FROM AUTHOR]

Lanthanum doped SiC nanowires (La-doped SiC NWs) were prepared using the chemical vapor reaction technique at different heat preservation times. Polycarbosilane was employed as a provider of both the Si and C elements. The characterization results suggested that the products were β-SiC. The nanowires straightened, the diameter of the nanowires became larger, and the content of La reduced with increasing heat preservation time. Meanwhile, the coating layer of SiO2 obviously dwindled. The XPS spectrogram revealed that the existence of the element La in the product was in the form of a trivalent ion, La3+. The forbidden band width dropped from 1.37 to 0.8 eV after doping with La, which was calculated using Material Studio 4.2 software. When a heat preservation time of 120 min was used, the content of La had a minimum of 0.87 at%, and the turn-on field and the threshold field of the product were 1.2 and 5.0 V μm−1, respectively. A synergetic influence mechanism was put forward to explain the effects of the morphology and the La content on the field emission (FE) properties of the La-doped SiC NWs. This work could act as a reference article for those researching FE properties of other one-dimensional nano-materials. [ABSTRACT FROM AUTHOR]

In this paper, we constructed oxygen vacancy-containing Bi2O3 nanosheet arrays (OV-Bi2O3 NSAs) with typical mesoporous structures and CoNi2S4 nanoparticles (CoNi2S4 NPs) grown on N-doped graphene nanotubes (N-GNTs) through facile approaches. The as-fabricated OV-Bi2O3 NSAs and CoNi2S4 NPs were specifically used as advanced freestanding negative and positive electrodes, respectively, for application in asymmetric supercapacitors (ASCs). The introduction of ample vacancies to Bi2O3 NSAs can not only enhance their electronic conductivity and donor density but also ameliorate their surface features, which greatly enables the transport of electrolyte ions and electrons, giving rise to rapid redox processes at the Bi2O3/electrolyte interfaces. Benefiting from the introduction of the oxygen vacancies and the particular morphologies, as well as the synergistic contributions of various components in the nanohybrid electrode, the N-GNTs@OV-Bi2O3 NSA electrode delivers a substantially appreciable specific capacitance of 643 F g−1 at 1 A g−1 coupled with exceptional rate capability. Moreover, the as-synthesized N-GNTs@CoNi2S4 NP electrode also presents an ultrahigh specific capacitance of 2142 F g−1 at 2.5 A g−1. More importantly, the assembled N-GNTs@OV-Bi2O3 NSAs//N-GNTs@CoNi2S4 NP asymmetric supercapacitor with an expanded operation voltage of 1.6 V yields a maximum specific energy density of 86.6 W h kg−1 at a power density of 1.6 kW kg−1 and outstanding cycling characteristics (85% capacitance retention after 10 000 cycles). This study underscores the potential significance of both incorporating oxygen vacancies into metal compounds and integrating the conductive skeleton with the active materials as a strategy for augmenting the electrochemical performances of the electrode materials. [ABSTRACT FROM AUTHOR]

A facile, controllable two-step electrodeposition synthesis route was developed, whereby a honeycomb-like amorphous cobalt sulfide architecture was obtained via direct growth on a glassy carbon electrode (GCE) functionalized by a reduced graphene oxide–poly(3,4-ethylenedioxythiophene) (rGO–PEDOT) composite film as an electrode for glucose detection. This electrodeposition method is binder-free, rapid, low-cost and preparation-controlled. The effects of the concentration ratio between CoCl2·6H2O and thiourea, deposition scanning rate and deposition cycles on glucose detection were investigated, and the optimum preparation conditions were determined. The characterization results indicated that the honeycomb-like cobalt sulfide architecture was formed by growing vertically amorphous CoxSy nanosheets with a thickness of about 20–50 nm on the rGO–PEDOT surface, and the morphology of cobalt sulfide could be controlled by regulating the deposition cycles. Under optimal conditions, the sensor exhibited a wide linear range from 0.2 to 1380 μM (R2 = 0.9976), a sensitivity of 113.46 μA mM−1 cm−2, a low detection limit of 0.079 μM and a response time of 3 s. This sensor also displayed good selectivity, reproducibility and repeatability for non-enzyme glucose sensing. More importantly, the sensor was successfully used to determine glucose in human blood serum samples, and the results were consistent with hospital test results. [ABSTRACT FROM AUTHOR]

Amphiphilic star-shaped block copolymers with biodegradable and biocompatible sequences are attracting increasing attention in biomaterials. Herein, we report the synthesis, characterization, solution properties, and biocompatibility of amphiphilic three-armed star-shaped poly(sarcosine)-block-poly(ε-caprolactone) (s-PSar-b-PCL) diblock copolymers. Tris-(2-aminoethyl)amine initiated ring-opening polymerization (ROP) of sarcosine N-carboxyanhydrides in a controlled manner, yielding star-shaped poly(sarcosine)s (s-PSars) with predictable molecular weights (from 3.3 to 9.8 kg mol−1) and narrow dispersities (ĐM ＜ 1.1). Well-defined amphiphilic s-PSar-b-PCL diblock copolymers were synthesized by ROP of ε-caprolactone using s-PSars as the macroinitiators in one pot. The obtained s-PSars and s-PSar-b-PCL diblock copolymers were characterized using 1H NMR, 13C NMR, MALDI-ToF MS, and size-exclusion chromatography (SEC). Intrinsic viscosities ([η]) of the s-PSar and s-PSar-b-PCL were estimated using SEC-MALS-VISC-DRI. Dynamic light scattering and transmission electron microscopy analysis showed that the s-PSar-b-PCL diblock copolymers self-assembled into spherical aggregates with average hydrodynamic diameters of 56–169 nm in aqueous solution. MTT assays (cell viability test) certified the biosafety (relative cell viability ＞80%) of the copolymers and their self-assembled nanostructures. Taken together, we (i) synthesized the novel s-PSar-b-PCL diblock copolymers, (ii) investigated the solution properties of the s-PSar-b-PCLs and s-PSars, and (iii) demonstrated the biocompatibility of s-PSar-b-PCLs. [ABSTRACT FROM AUTHOR]

To design and synthesise highly efficient photocatalysts by a facile, environmental friendly, and economical method has become of vital importance in the photocatalytic field. With the assistance of a simple microwave treatment for 40 min, the reduced graphene oxide/Ag3PO4 (rGO/Ag3PO4) visible-light-response photocatalyst can be rapidly synthesized under the atmosphere. TEM results show that the irregular Ag3PO4 particles are distributed on the surface of the rGO sheet. In the photo-degradation process of methyl orange (MO), the optimum photocatalytic activity of rGO (1.5%)/Ag3PO4 under simulated daylight is almost 2 times higher than pure Ag3PO4. Obviously, this facile method paves a convenient way to prepare visible-light-response Ag3PO4-based composites with high photocatalytic efficiency in a large scale and also to reduce the high cost of Ag3PO4 for practical uses. [ABSTRACT FROM AUTHOR]

Nitrogen-doped SiC nanowires (N-doped SiC NWs) with a nitrogen content from 0.975 wt% to 2.265 wt% have been synthesized via a one-step chemical vapor reaction (CVR), where melamine served as both the carbon and nitrogen source. Interestingly, the morphology of the products changed from slightly curled to very curled with crowding together with the increase of N dopants, which was interpreted reasonably by the proposed N-doping growth model of SiC NWs. In addition, according to the electronic structure calculation results, the band gap is narrowed progressively with the increase of N content, which greatly enhances the field emission (FE) properties. However, the experimental results of the FE measurements substantiate that only when the N content takes an optimal value can the N-doped SiC NWs act as candidates for field emitters with very low turn-on fields (Eto) of 1.5 V μm−1 and threshold fields (Ethr) of 4 V μm−1. On the basis of the aforementioned phenomenon, a universal cooperativity mechanism was put forward to explain the effect of the N content and morphology on the FE properties of the N-doped SiC NWs. [ABSTRACT FROM AUTHOR]