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The iron and nitrogen co-doped porous carbon supported Au nanoparticle catalysts (Au/FeNPC) are synthesized via a facile pyrolysis method. The morphology, crystal structure, surface composition, and chemical state of the Au/FeNPC catalysts are investigated by transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The catalytic performances of the Au/FeNPC for BH4− oxidation reaction (BOR) are investigated by cyclic voltammetry (CV), chronoamperometry (CA), chronopotentiometry (CP), and linear voltammetric sweep (LSV). Among the as-prepared Au/FeNPC catalysts, Au/FeNPC-40 catalyst possesses the highest catalytic activity for BOR, and the BOR peak current density on the Au/FeNPC-40 electrode is up to 45.4 mA cm−2 with the high transferred electron number of 7.0.

Carbon-supported Au-doped N-C-coated CoFe alloy nanocomposite electrocatalysts (Au/CoFe@CN/C) are prepared and applied to BH4− electrooxidation. The physical and electrochemical properties of the catalysts are characterized and tested by X-ray diffraction, transmission electron microscopy, cyclic voltammetry, chronamperometry, chronopotentiometry, and rotating disk electrode voltammetry. The results show that Au(50)/CoFe@CN(50)/C has excellent catalytic performance for BH4− electrooxidation, high charge transfer number up to 6.4, and low precious metal content, making it a promising anode electrocatalyst of direct borohydride fuel cell.

Graphdiyne (GDY), a novel two-dimensional (2D) carbon material with sp- and sp2-hybridized carbon atoms, has earned a lot of attention in recent years. Owing to its low reduction potential and highly conjugated electronic structure, it can be used as a reducing agent and stabilizer for the electroless deposition of highly dispersed Au nanoparticles. In this paper, we observe that exfoliated GDY (eGDY), the exfoliation of bulk GDY into single- or few-layered GDY in aqueous solution, can be used as an excellent substrate for the electroless deposition of very small Au nanoparticles to form a Au/eGDY nanocomposite that exhibits higher catalytic performance for the reduction of 4-nitrophenol. The higher catalytic performance is considered to arise from the high specific surface area of eGDY and the electroless deposition of active metal catalysts with eGDY as the support. Our results inspired the present investigation into the use of eGDY for the development of highly efficient catalysts.

In this paper, carbon-supported nickel hydroxide-doped platinum (Pt/Ni(OH)2/C) nanocatalysts are synthesized by a two-step method, and the morphology and structure of Pt/Ni(OH)2/C are studied by transmission electron microscope and X-ray diffraction analysis. The electrocatalytic performance of the Pt/Ni(OH)2/C for borohydride oxidation reaction (BOR) is studied by using cyclic voltammetry, chronoamperometry, chronopotentiometry, and rotating disc electrode voltammetry. The Pt/Ni(OH)2/C catalysts show much better catalytic performance than Pt/C, and Pt(50)/Ni(OH)2(50)/C exhibits the best catalytic performance among all as-prepared Pt/Ni(OH)2/C catalysts. Moreover, the electron transfer number (n) related to BOR is evaluated, and n of 3.5 is achieved on Pt(50)/Ni(OH)2(50)/C electrode.

An electrocatalyst for BH4− electrooxidation is facilely achieved via a two-step method, which consists of carbon substrate, Ni(OH)2 nanospheres and Au nanoparticles. Results of scanning electron microcopy, transmission electron microscopy, and X-ray diffraction show that Au nanoparticles dispersedly grow on both surfaces of carbon substrate and carbon-supported Ni(OH)2 nanospheres. The electrocatalytic activity of the as-prepared catalysts loaded with different amounts of Au and Ni(OH)2 are explored through cyclic voltammetry, chronoamperometry, chronopotentiometry, and rotating disc electrode voltammetry. Among the prepared catalysts, Au(50)/Ni(OH)2(50)/C catalyst displays the best electrocatalytic activity for BH4− electrooxidation, and the lower content of noble metal and the higher catalytic activity for BH4− electrooxidation make Au(50)/Ni(OH)2(50)/C a promising anode catalyst in application of direct borohydride fuel cells.

Pd/C and Pd-Co/C nanocatalysts are prepared via a simple and environmentally friendly method and are used as anodic catalyst for direct borohydride–hydrogen peroxide fuel cells. X-ray diffraction and transmission electron microscopy results indicate that Pd and Pd-Co nanoparticles adhere on carbon with the mean diameter of about 4 nm. The cyclic voltammetry, chronoamperometry, chronopotentiometry, and rotating disc electrode voltammetry results show that the electrocatalytic activity of Pd-Co/C is higher than that of Pd/C, especially Pd67Co33/C which shows the highest electrocatalytic activity for BH4− electro-oxidation with the electron-transfer number of 4.9 related to BH4− electro-oxidation reaction. The single direct borohydride–hydrogen peroxide fuel cell with Pd67Co33/C anode obtains the maximum power density as high as 66.84 mW cm−2 at 25 °C.

Photocatalytic water splitting for H2 evolution is appealing for transforming solar energy into clean chemical fuel. This technique generally requires noble metals as H2 evolution cocatalysts to fa...

A structure evolution map of face-centered cubic (fcc)-structured thiolate-ligand protected gold nanoclusters is outlined on the basis of total structure determination of a new 6e Au21(SR)15 (R = tert-butyl, t-Bu) cluster. The structural evolution map described some basic structural evolution patterns such as a triangle-Au3 and tetrahedron-Au4 associated gold-core evolution pattern and the periodic or symmetric growth of gold cores and ligand shells. According to the structural evolution map, a topological structure–electronic structure relationship is also proposed. The delocalized valence electronic properties of any fcc-structured gold clusters may be expressed as the linear combinations of the molecular orbitals of the fragment 2e units (Au3+ and Au42+). The structural disciplines and topological structure–electronic structure relationships reported in this work laid a basis for understanding the structural evolution and electronic structure of fcc-structured thiolate-protected gold nanoclusters. Part...

Carbon-supported bimetallic platinum–iron nanocatalysts (Pt–Fe/C) with various proportions of atoms, applied to direct borohydride/peroxide fuel cell (DBHFC) anode catalyst, are facilely prepared via a simple and low-cost chemical route in aqueous solution at ambient temperature. Transmission electron microscopy and X-ray diffraction results show the Pt–Fe alloy structure’s existence as well as the mean crystallite size of around 3 nm for Pt–Fe nanoparticles. Enhanced catalytic activity of Pt–Fe/C to BH4– electro-oxidation has been observed in electrochemical test (chronoamperometry, cyclic voltammetry, single fuel cell test, and rotating disc electrode voltammetry) results, and Pt67Fe33/C shows the best catalytic performance. High maximum power density of 65 mW cm–2 for DBHFC is acquired by using Pt67Fe33/C as anode at 25 °C. Furthermore, the electron-transfer number (n) related to BH4– oxidation is evaluated, and n of 4.9 can be achieved on Pt67Fe33/C electrode.

Li-rich material 0.4Li2MnO3·0.6LiNi1/3Co1/3Mn1/3O2 with a layered/spinel heterostructure is synthesized by a simple strategy. On the basis of structure and morphology analyses, it is revealed that the as-prepared Li-rich material possesses both porous micronano structure and integral layered-spinel heterostructure. Moreover, the obtained layered-spinel cathode material possesses prominent electrochemical characteristics, especially its rate capability. The initial discharge capacity of the as-prepared material is 269 mAh g–1 with a high Coulombic efficiency of 90.3%. The material delivers discharge capacities of 239 mAh g–1 at 0.5C, 195 mAh g–1 at 5C, and 175.8 mAh g–1 even at 10C. Also, the capacity retention of the cell is still as high as 80% at high current density (5C) after 200 cycles. The addition of spinel can inhibit the collapse of the material structure and voltage fading upon cycling. The 3D spinel Li4Mn5O12 phase in the Li-rich compound could provide a fast Li-ion diffusion pathway and a poro...

Mesoporous Ni-P@NiCo2O4 composite materials have been fabricated via a facile strategy including solvothermal synthesis of Ni-P and subsequent chemical deposition of NiCo2O4. Due to the synergistic effect between Ni-P and NiCo2O4, the Ni-P@NiCo2O4 composite materials exhibit an enhanced performance (1240 F g−1 at 1 A g−1, 668 F g−1 at 16 A g−1) compared with the bare Ni-P materials (717 F g−1 at 1 A g−1, 106 F g−1 at 16 A g−1) and NiCo2O4 materials (741 F g−1 at 1 A g−1, 457 F g−1 at 16 A g−1). Furthermore, the AC//Ni-P@NiCo2O4 asymmetric capacitor exhibits superior energy/power densities (13.3 Wh kg−1/5.7 kW kg−1) and cycling behavior (78.3% retention after 10,000 cycles at 4 A g−1) than the AC//Ni-P asymmetric capacitor (7.4 Wh kg−1/5.7 kW kg−1, 63.4% retention after 10,000 cycles at 4 A g−1) and AC//NiCo2O4 asymmetric capacitor (10.4 Wh kg−1/5.6 kW kg−1, 32.4% retention after 10,000 cycles at 4 A g−1). The high performance makes the mesoporous Ni-P@NiCo2O4 composite materials promising electrode materials for supercapacitors.

In this study, preparation of nitrogen- and oxygen-codoped porous carbonaceous foam and its application as metal nanoparticles catalysts support for direct methanol fuel cell (DMFC) were presented. Tadpole-like single chain polymer nanoparticles stabilized water-in-acrylonitrile/divinyl benezene high internal phase emulsion (HIPE) was firstly prepared, and the formed HIPE was then converted into polymer of high internal phase emulsion (polyHIPE) through a radical polymerization reaction. Subsequently, the formed acrylonitrile/divinyl benezene based polyHIPE was hypercrosslinked via FeCl3 catalyzed Friedel-Crafts reaction in 1,2-dichloroethane. After pyrolysis of the hypercrosslinked polyHIPE at elevated temperature under N2 atmosphere, nitrogen- and oxygen-codoped porous carbonaceous foam exhibiting highly interconnected macroporous cells and a micro-/mesoporous carbon skeleton (carboHIPE) was obtained. The resultant carboHIPE was further applied as the support for Pt and Ru bimetal nanoparticles. Well-dispersed PtRu bimetal nanoparticles with a smaller size were perfectly dispersed on the surface of carboHIPE in the form of alloy phase. The PtRu alloy nanoparticles decorated carboHIPE (PtRu/carboHIPE) demonstrated superior electrocatalytic performances towards the methanol electrooxidation by comparison with Pt/carboHIPE and commercial PtRu/C with almost same Pt content, such as the higher current density, the better long term stability and the improved CO-resistance.

Nanoporous carbon (NPC) supported Pt-Cu nanocomposites (PtxCu/NPC) with different Pt/Cu molar ratios have been successfully synthesized via NaBH4 reduction method and used as anode catalysts for direct borohydride-hydrogen peroxide fuel cell (DBHFC). The as-synthesized PtxCu/NPC electrocatalysts are characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), cyclic voltammetry (CV), chronoamperometry (CA), rotating disc electrode (RDE) and fuel cell test. It has been found that the PtCu nanoparticles are uniformly dispersed on the surface of the NPC support with average size of about 2.3 nm. Besides, the PtxCu/NPC catalysts show higher activities for borohydride oxidation than that of monometallic Pt/NPC and Vulcan XC-72 carbon supported Pt2Cu (Pt2Cu/XC-72) catalysts. Especially, the DBHFC equipped with Pt2Cu/NPC as anode catalyst shows the maximum power density of 89 mW cm−2 at 25 °C.

A series of nanoporous carbon supported Pd–Zn catalysts (Pd x Zn/NPC, x = 1, 2, 3) have been successfully prepared via impregnation-reduction method and firstly employed as anode catalysts for direct borohydride-hydrogen peroxide fuel cell (DBHFC). The properties of the Pd x Zn/NPC electrocatalysts are characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), cyclic voltammetry (CV), chronoamperometry (CA) and single fuel cell test. The TEM images of Pd 2 Zn/NPC catalyst reveal that the metal particles with a size of approximately 3.1 nm are uniformly dispersed on the nanoporous carbon (NPC). Besides, all the Pd x Zn/NPC catalysts exhibit enhanced catalytic activity and stability for BH 4 − electrooxidation compared to monometallic Pd/NPC in the electrochemical tests. Especially, the Pd 2 Zn/NPC catalyst exhibits the highest electrocatalytic activity toward borohydride oxidation among the four catalysts. Moreover, the DBHFC equipped with the Pd 2 Zn/NPC anode also presents an excellent cell performance with the maximum power density as high as 103.93 mW cm −2 at 25 °C.

The nanoporous carbon (NPC) is synthesized by carbonization of metal–organic framework-5 (MOF-5, [Zn4O(bdc)3], bdc = 1,4-benzenedicarboxylate) with furfuryl alcohol (FA) as carbon source and used as the carrier of the anode catalyst for the direct borohydride–hydrogen peroxide fuel cell (DBHFC). Then the NPC-supported Pt anode catalyst (Pt/NPC) is firstly prepared by a modified NaBH4 reduction method. The obtained Pt/NPC catalyst is characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive spectrometry (EDS), cyclic voltammetry, chronopotentiometry, chronoamperometry and fuel cell test. The results show that the Pt/NPC is made up of the spherical Pt nanoparticles which disperse uniformly on the surface of the NPC with average size 2.38 nm, and exhibits 36.38% higher current density for directly borohydride oxidation than the Vulcan XC-72 carbon supported Pt (Pt/XC-72). Besides, the DBHFC using the Pt/NPC as anode electrocatalyst shows the maximum power density as high as 54.34 mW cm−2 at 25 °C.

Activated nanoporous carbon (A-NPC) has been synthesized via KOH activation of a nanoporous carbon (NPC) prepared using a template metal–organic framework-5 (MOF-5), and it is firstly used as an anode electrocatalyst carrier of Au nanoparticles in borohydride–hydrogen peroxide fuel cells (DBHFCs). The samples are characterized by N2 adsorption–desorption isotherms, transmission electron microscopy (TEM), X-ray diffraction (XRD), cyclic voltammetry (CV), chronopotentiometry (CP), chronoamperometry and fuel cell tests. It has been found that the A-NPC achieves a surface area up to 2296 m2 g−1 and a pore volume of 1.59 cm3 g−1. The mean particle size of Au crystallites dispersed uniformly on the surface of the A-NPC carrier is only 2.9 nm. Besides, the peak current density for direct borohydride oxidation of the Au/A-NPC (49.1 mA cm−2) is 13.6% higher than that of the untreated NPC supported Au (43.2 mA cm−2), and 63.1% higher than that of commercial Vulcan XC-72R supported Au (30.1 mA cm−2). The DBHFC using the Au/A-NPC as anode electrocatalyst can obtain a maximum power density of 48.2 mW cm−2 at 25 °C.

Lithium titanium phosphate (LiTi 2 (PO 4 ) 3 ) has been successfully synthesized by a polyvinyl alcohol (PVA) assisted sol–gel method. To further improve its electrochemical properties, a ball-milling process with various amount of acetylene black (AB) has been used to form LiTi 2 (PO 4 ) 3 -AB nanocomposites (the weight ratio of acetylene black is 5 wt.%, 10 wt.%, 15 wt.% and 20 wt.%). The samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Electrochemical performance of the samples is characterized by the charge–discharge test, cyclic voltammetry (CV), electrochemical impedance spectroscopic studies (EIS), and galvanostatic intermittent titration technique (GITT). The results show that the ball-milling process enables LiTi 2 (PO 4 ) 3 nanoparticles to network with conductive acetylene black, which offers better electrochemical performance. Especially, LiTi 2 (PO 4 ) 3 -AB nanocomposite with 15 wt.% acetylene black shows the best electrochemical properties, which delivers the highest specific capacity and the best cycle performance. Besides, the thermodynamics properties of as-prepared samples are also been studied.

A spherical lithium-rich layered cathode material with an average composition of Li 1.13 [Mn 0.534 Ni 0.233 Co 0.233 ] 0.87 O 2 was successfully synthesized via co-precipitation route. In this material, each particle was consisted of an inner core and a stable concentration-gradient outer layer in which manganese content was gradually increased. The concentration-gradient material showed a typical rhombohedral LiNiO 2 -like layered structure with the existence of the monoclinic Li 2 MnO 3 -type integrated component. It can be found from the cross-sectional SEM images that the concentration-gradient particle was quite homogeneous without any apparent gap between the inner core and the concentration-gradient outer layer. Furthermore, according to the EDXS analysis, the concentrations of Mn, Ni, and Co kept almost constant throughout the core, and the concentration of Mn increased gradually within the outer layer of the particle. The lithium-rich layered material can deliver a very high capacity of 220 mAh g −1 , and the excellent cycle life and improved thermal stability were achieved by the concentration-gradient outer layer. The results here indicate that the lithium-rich layered material with a manganese-rich concentration-gradient outer layer will be a promising cathode material for advanced lithium ion batteries with high capacity, long cycle life, and improved safety.

With the direct carbonization using polyaniline/activated mesocarbon microbead (PANI/ACMB) composites as the precursor and subsequent activation treatment with 16 M HNO 3 , the activated nitrogen-enriched novel carbons (a-NENCs) can be prepared. Scanning electron microscopy (SEM), Fourier infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and nitrogen adsorption/desorption isotherm at 77 K are utilized to characterize the structure, morphology and physicochemical properties of the a-NENCs. The result shows that the a-NENCs keep the original leechee-like morphology of the PANI/ACMB composites. The supercapacitive performances of the a-NENCs are investigated with cyclic voltammetry (CV), galvanostatic charge/discharge tests, impedance spectroscopy (EIS) and cycle life measurements in 6 M KOH. The results based on galvanostatic charge/discharge tests demonstrate that the maximum specific capacitance of the a-NENCs electrode is 385 F g −1 . Meanwhile, the specific capacitance of the button supercapacitor using a-NENCs as electrode active material is as high as 89.5 F g −1 at the charge/discharge current density of 500 mA g −1 . These remarkable results demonstrate the exciting commercial potential for high performance, environmentally friendly and low-cost electrical energy-storage devices based on this new material.

Porous calcium carbide-derived carbon (CCDC) has been prepared by one-step route from CaC2 in a freshly prepared chlorine environment at lower temperature, and following activated by ZnCl2 to get activated CCDC. The performances of the supercapacitors based on activated CCDC as electrode active material in aqueous KOH, K2SO4, KCl and KNO3 electrolytes are studied by cyclic voltammetry, constant current charged/discharged, cyclic life and electrochemical impedance spectroscopy. It has been found that the supercapacitor using 6 M KOH as electrolyte shows an energy density of 8.3 Wh kg−1 and a power density of 1992 W kg−1 based on the total weight of the electrode active materials with a voltage range 0 V–1 V. Meanwhile, the specific capacitance of the supercapacitor in 6 M KOH electrolyte is 68 F g−1 at the scan rate of 1 mV s−1 in the voltage range of 0 V–1 V, the charge-transfer resistance is extremely low and the relaxation time is the least of all. The supercapacitor also exhibits a good cycling performance and keeps 95% of initial capacity over 5000 cycles.

The activated nitrogen-enriched novel carbons (a-NENCs) have been prepared by direct carbonization of polyaniline/activated mesocarbon microbead composites and further activated by 16 M HNO3. The electrochemical performances and supercapacitive behaviors of the a-NENCs in 6 M KOH, 1 M H2SO4, and 0.5 M K2SO4 solutions are evaluated by cyclic voltammetry, galvanostatic charge/discharge, electrochemical impedance spectroscopy, cyclic life, leakage current, and self-discharge measurements. The results demonstrate that the supercapacitors perform definitely supercapacitive behaviors; especially in 6 M KOH electrolyte, the supercapacitor represents much better electrochemical performance with more excellent reversibility, shorter relaxation time of 1.11 s, and nearly ideal polarizability. The maximum specific capacitance of the supercapacitors using a-NENCs as active electrode material is 85.1 F g−1 at a rate of 500 mA g−1 in 6 M KOH. These outcomes indicate that the 6 M KOH aqueous solution is a promising electrolyte for the supercapacitor with a-NENCs as electrode material.

In current study, nanowhisker-like NiO/carbon aerogel microbead (NiO/CAMB) composites with chestnut-like core–shell structure are prepared by in situ encapsulating method. The structure and morphology of NiO/CAMB are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Results indicate that the appearance of composite becomes chestnut-like morphology with core–shell structure when NiO is coated. Electrochemical performances of the NiO/CAMB composites with different NiO contents are evaluated by using cyclic voltammetry (CV), galvanostatic charge–discharge and electrochemical impedance spectroscopy (EIS). Results show that the supercapacitive behaviors of NiO/CAMB composites are largely improved due to the combination of electrical double-layer capacitance of CAMB and pseudo-capacitance based on the redox reaction of NiO. Especially, the 15%-NiO/CAMB composite exhibits the best capacitive properties, its specific capacitance is up to 356.2 F g −1 . Besides, the symmetric supercapacitor using 15%-NiO/CAMB composite as the electrode active material shows stable cycling performance.

Carbon supported Pt–Sn bimetallic nanoparticles (Pt–Sn/C) are prepared by a modified NaBH 4 reduction method in aqueous solution at room temperature, and used as the anode electrocatalyst for direct borohydride–hydrogen peroxide fuel cell (DBHFC). The physical and electrochemical properties of the as-prepared electrocatalysts are investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), cyclic voltammetry (CV), chronoamperometry (CA) and fuel cell test. XRD results show that the diffraction peaks in Pt–Sn/C catalyst shift slightly to lower 2θ values with the increase of Sn content compared with that of Pt/C catalyst, suggesting the formation of Pt–Sn alloying. TEM results show that the morphologies of Pt–Sn bimetallic nanoparticles are uniformly spherical with the particle size of about 3 nm on the carbon surface. Besides, it has been found that the Pt–Sn/C catalysts have much higher catalytic activity for the direct oxidation of BH 4 − than Pt/C catalyst, especially the Pt 67 Sn 33 /C catalyst presents the highest catalytic activity among all as-prepared catalysts. The DBHFC with Pt 67 Sn 33 /C anode catalyst and Pt/C cathode catalyst obtains the maximum power density as high as 91.5 mW cm −2 at 25 °C.

The graphene supported Pt nanoparticles are prepared by ethylene glycol reduction method. The obtained Pt/graphene (Pt/G) nanocomposites are characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). TEM images show that the spherical Pt nanoparticles with sizes of 3.1 nm disperse uniformly on the surface of the graphene, which is consistent with the XRD date of 2.97 nm. The Pt/G nanocomposites show electrochemically active surface area (ECSA) of 62.7 m2/g. It has been found by electrochemical measurements (i.e., cyclic voltammetry, chronoamperometry) that the Pt/G nanocomposites exhibit good electrocatalytic activity and stability toward borohydride oxidation. Besides, the Pt/G nanocomposites are used as anode electrocatalyst in a direct borohydride fuel cell at 298 K, and the maximum power density is 42 mW/cm2, which is apparently higher than Vulcan XC-72R supported Pt (Pt/C) nanoparticles (34 mW/cm2).

Carbon-supported Pt–Co nanoparticle catalysts (Pt–Co/C) with a mean crystallite size of approximate 2 nm are prepared by a modified NaBH4 reduction method in aqueous solution at room temperature and employed as anode catalyst for direct borohydride-hydrogen peroxide fuel cell (DBHFC). The physical and electrochemical properties are investigated by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), chronoamperometry (CA) and fuel cell test. The results show that Pt–Co/C catalyst presents more excellent performance as DBHFC anode catalyst compared with Pt/C catalyst, especially, Pt67Co33/C catalyst presents the highest catalytic activity for BH 4 − electrooxidation among all as-prepared catalysts. The single DBHFC using Pt67Co33/C as anode catalyst and Pt/C as cathode catalyst obtains the maximum power density as high as 79.7 mW cm−2 at 25 °C.

Au/graphene nanocomposites are prepared via a one-pot chemical reduction process at room temperature, using graphene oxide (GO) and chloroauric acid (HAuCl4) as precursors. The obtained Au/graphene nanocomposites are characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). TEM shows that the Au nanoparticles with size of approximately 8.7 nm disperse randomly on the surface of graphene. XPS confirms that the Au/graphene nanocomposites show a higher atomic percentage of C/O (6.3/1), in contrast to its precursor GO (2.2/1). Electrochemical studies reveal that the Au/graphene nanocomposites have electrochemically active surface area of 9.82 m2 g−1. Besides, the influence of borohydride concentration on the as-prepared Au/graphene nanocomposites is investigated in details by cyclic voltammetry, chronoamperometry, and chronopotentiometry. The results indicate that high concentration of borohydride can significantly improve the electrochemical performance of the Au/graphene catalyst.

Carbon supported Pd hollow nanospheres (HN-Pd/C) are prepared by employing cobalt nanoparticles as sacrificial templates at room temperature in aqueous solution, and used as the anode electrocatalyst for direct borohydride-hydrogen peroxide fuel cell (DBHFC). The physical and electrochemical properties of the as-prepared nanospherical electrocatalysts are investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), linear sweep voltammetry (LSV), chronoamperometry (CA), chronopotentiometry (CP) and fuel cell test. The results show that the Pd nanospheres supported on the carbon are coreless and composed of a series of Pd nanoparticles with the average crystallite size of about 3.8 nm. Besides, the HN-Pd/C exhibits distinctly higher electrocatalytic activity for BH 4 − electrooxidation than the carbon supported Pd solid nanoparticles (SN-Pd/C), and the DBHFC using HN-Pd/C as anode electrocatalyst shows as high as 48.4 mW cm −2 power densities at a discharge current density of 54.8 mA cm −2 . Therefore, the HN-Pd/C catalyst can apparently improve the catalytic activity of BH 4 − electrooxidation and imply a promising application in the DBHFC.

A series of Mn2O3/carbon aerogel microbead (Mn2O3/CAMB) composites for supercapacitor electrodes have been synthesized by in situ encapsulation method. The structure and morphology of Mn2O3/CAMB are characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectrum and scanning electron microscopy (SEM). Electrochemical performances of the synthesized composites are evaluated by cyclic voltammetry and galvanostatic charge/discharge measurement. All the composites with different Mn2O3 contents show higher specific capacitance than pure CAMB due to the pseudo-capacitance of the Mn2O3 particles dispersed on the surface of CAMB. The highest specific capacitance is up to 368.01 F g−1 when 10 wt% Mn2O3 is coated on the surface of CAMB. Besides, 10%-Mn2O3/CAMB supercapacitor exhibits excellent cyclic stability, the specific capacitance still retains 90% of initial capacitance over 5000 cycles.

Bismuth–vanadium oxyfluoride (Bi 2 VO 5 F) has been synthesized using a simple, solid-state reaction process at different sintering temperatures. The structure and performance of the samples have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge/discharge experiments. The results show that bismuth–vanadium oxyfluoride belongs to a tetragonal crystal system with space group I4mm . The sample that was synthesized at 550 °C (P550) exhibits relatively good electrochemical properties. Sample P550 shows a high, initial discharge capacity of 222 mAh g −1 at a rate of 100 mA g −1 between 1.4 and 3.5 V. Sample P550 also shows acceptable electrochemical cycling properties. After the first cycle, the discharge specific capacity remains between 106 and 155 mAh g −1 , which plateaus between 2.1 and 1.9 V during the first 15 cycles.

The carbon supported Pt hollow nanospheres were prepared by employing cobalt nanoparticles as sacrificial templates at room temperature in aqueous solution and used as the anode electrocatalyst for direct borohydride-hydrogen peroxide fuel cell (DBHFC). The physical and electrochemical properties of the as-prepared electrocatalysts were investigated by transmission electron microscopy (TEM), X-ray diffraction (XRD), cyclic voltammetry (CV), chronoamperometry (CA), chronopotentiometry (CP) and fuel cell test. The results showed that the carbon supported Pt nanospheres were coreless and composed of discrete Pt nanoparticles with the crystallite size of about 2.8 nm. Besides, it has been found that the carbon supported Pt hollow nanospheres exhibited an enhanced electrocatalytic performance for BH 4 − oxidation compared with the carbon supported solid Pt nanoparticles, and the DBHFC using the carbon supported Pt hollow nanospheres as electrocatalyst showed as high as 54.53 mW cm −2 power density at a discharge current density of 44.9 mA cm −2 .

Co 3 O 4 /carbon aerogel microbead (Co 3 O 4 /CAMB) composites are prepared by in situ coating method and their supercapacitive behaviors are investigated. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectrum, scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectrum are used to characterize the structure and morphology of Co 3 O 4 /CAMB. The results show that nano-sized Co 3 O 4 particles are homogenously encapsulated on the surface of CAMB. Electrochemical performances of the composite electrodes with different Co 3 O 4 amount are studied by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge/discharge measurements. It is found that Co 3 O 4 /CAMB composites show better electrochemical performance than CAMB, and the optimum content of Co 3 O 4 in Co 3 O 4 /CAMB composites is 10 wt.%. The specific capacitance of 10%–Co 3 O 4 /CAMB composite in 6 mol L −1 KOH electrolyte is about 350.18 F g −1 at a current density of 1 A g −1 . Moreover, 10%–Co 3 O 4 /CAMB composite supercapacitor exhibits relatively good high-rate capability and excellent cycle life.

Carbon aerogel (CA) microspheres have been successfully synthesized by an inverse emulsion polymerization and characterized by scanning electron microscopy (SEM), N2 sorption isotherm and X-ray diffraction (XRD). The results show that the size and pore characteristics of carbon microsphere obviously depend on stirring speed and concentration of surfactant in the emulsion polymerization process. The resultant CA microspheres are amorphous carbon structure with the size ranging from about 2 to 50 μm by changing the stirring speed. CA microspheres with SBET of 414–603 m2 g− 1 and Vmeso of 0.028–0.432 cm3 g− 1 are synthesized using different SPAN80 concentrations. The results of cyclic voltammetry indicate that the CA microspheres prepared at a stirring speed of 480 rpm and at Vs/Vh = 0.01 have ideal supercapacitive behavior in 6 M KOH electrolyte, the maximum specific capacitance of the electrode reaches 180 F g− 1.

The carbon supported Au 80 Ni 20 , Au 58 Ni 42 and Au 41 Ni 59 nanoparticles for the application of direct borohydride-hydrogen peroxide fuel cell (DBHFC) are synthesized in a sodium bis(2-ethylhexyl) sulfosuccinate (AOT) reverse micelle system. The physical and electrochemical properties are investigated by transmission electron microscopy (TEM), cyclic voltammetry, chronoamperometry, chronopotentiometry and fuel cell test. The TEM results reveal that the Au–Ni bimetallic particles are uniformly dispersed on carbon with narrow size distribution and regular spherical shape. The average size of the particles is about 3 nm. The electrochemical measurements show that Au–Ni bimetallic particles can apparently promote the electrode kinetics of BH 4 − oxidation. The DBHFCs using carbon supported Au–Ni bimetallic particles as anode electrocatalysts are fabricated. The results show that the performance of DBHFC using Au 58 Ni 42 /C as anode electrocatalyst excels markedly to the others, and the maximum power density of 45.74 mW cm −2 is obtained at 20 °C.

Polypyrrole (PPy)/carbon aerogel (CA) composite materials with different PPy contents are prepared by chemical oxidation polymerization through ultrasound irradiation and are used as active electrode material for supercapacitor. The morphology of PPy/CA composite is examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that PPy is deposited onto the surface of CA. As evidenced by cyclic voltammetry, galvanostatic charge/discharge test and EIS measurements, PPy/CA composites show superior capacitive performances to CA, moreover, the results based on cyclic voltammograms show that the composite material has a high specific capacitance of 433 F g−1, while the capacitance of CA electrode is only 174 F g−1. Although the supercapacitor used PPy/CA as active electrode material has an initial capacitance loss due to the instability of PPy, the specific capacitance after 500 cycles stabilizes nearly at a fixed value.

Carbon aerogel (CA) microspheres were successfully synthesized by an inverse emulsion polymerization routine. Morphology and physical properties of the CA microspheres were characterized by scanning electron microscopy, N2 sorption isotherm, and transmission electron microscopy. The results showed that the CA microspheres were all fine spheres with diameters about 4 μm, and the CA microsphere was a typical mesoporous material with ordered mesoporous nano-network structure. The maximum capacitance of the electrode obtained from cyclic voltammetry was 187.08 F/g and the capacitance of the supercapacitor resulted from galvanostatic charge–discharge tests was up to 45.98 F/g. The supercapacitor using CA microsphere as electrode material presented a long cycle life, high charge–discharge efficiency, and low R s of 0.70 Ω in 6 M KOH electrolyte.

The non-isothermal crystallization kinetics of pure polyamide 6 (PA6) and novel PA6/silica-containing epoxy resin nanocomposites (EPA6N) were extensively studied by differential scanning calorimetry (DSC). Three methods, namely, the Avrami, the Ozawa, and the Mo, were used to describe the non-isothermal crystallization process of pure PA6 and EPA6N. It was found that all these three methods can describe the non-isothermal crystallization of pure PA6 very well, but the Ozawa analysis was rather inapplicable for the EPA6N. The Avrami analysis results show that the crystallization rate of EPA6N is faster than that of pure PA6, and the crystallization mechanism of EPA6N is different from that of pure PA6, in agreement with the Mo analysis results.

Platinum nanoparticles (Ptnano) were prepared and used in combination with single-wall carbon nanotube (SWNT) for fabricating electrochemical sensors with remarkably improved sensitivity toward diethylstilbestrol (DES). The glassy carbon (GC) electrode modified with SWNT/Ptnano composite film exhibited excellent electrochemical behaviors toward the redox of DES. Compared with the bare GC electrode and SWNTs film modified GC electrode, the redox peak currents at the SWNTs/Ptnano composite film modified GC electrode was enhanced greatly. The experimental parameters, which influence the peak current of DES, were optimized. Under optimal conditions, a linear response of DES was obtained in the range from 1.0 × 10−7 to 2.0 × 10−5 mol L−1 (R = 0.997) and with a limit of detect (LOD) of 1.5 × 10−8 mol L−1. The proposed procedure was successfully applied to determine the active ingredient in the DES tablet with satisfactory results.

The electroanalytical behaviors of the endocrine-disrupting chemical trifluralin have been studied at a nanostructuring electrode. The nanostructuring electrode was fabricated by coating a uniform multi-wall carbon nanotubes/dihexadecyl hydrogen phosphate (MWNTs/DHP) film on glassy carbon electrode (GCE). The reduction peak currents of trifluralin increased remarkably and the reduction peak potential shifted positively at the nanostructuring electrode, compared with that at a bare GCE. The results showed that this nanostructuring electrode exhibited excellent enhancement effects on the electrochemical reduction of trifluralin. Consequently, a simple and sensitive electroanalytical method was developed for the determination of trifluralin. Under optimal conditions, a linear response of trifluralin was obtained in the range from 5.0 × 10−9 to 6.0 × 10−6 mol L−1 (r = 0.998) and with a limit of detect (LOD) of 2.0 × 10−9 mol L−1. The proposed procedure was successfully applied to determine trifluralin in soil samples with satisfactory results.

As one of the most promising photocatalysts, TiO2 suffers from disadvantages of a wide band gap energy and especially the ultrafast recombination of photoinduced-charges, which limit its practical application for efficient solar water splitting. Here we show a hitherto unreported carbon/TiO2/carbon nanotube (CTCNT) composite featuring a TiO2 nanotube sandwiched between two thin tubes of carbon with graphitic characteristics. The carbon layer is only about 1 nm thick covering the surface of TiO2 nanotubes. The minimum bandgap between the edges of band tails for the CTCNTs can conjecturally be narrowed to 0.88 eV, and the measured apparent quantum efficiency of CTCNT in the ultraviolet light region is even close to 100%, indicating it can greatly enhance the utilization of sunlight and extremely suppress charge recombination. As a consequence, under illumination of one AM 1.5G sunlight, CTCNT can give a super-high solar-driven hydrogen production rate (37.6 mmol h−1 g−1), which is much greater than the best yields ever reported for TiO2-based photocatalysts. We anticipate this work may open up new insights into the architectural design of nanostructured photocatalysts for effective capture and conversion of sunlight.

A Li-rich layered cathode material Li1.15[(Ni1/3Co1/3Mn1/3)0.5(Ni1/4Mn3/4)0.5]0.85O2 with a spherical core–shell structure was firstly synthesized by a co-precipitation route. In this material, the Li1.15[Ni1/3Co1/3Mn1/3]0.85O2 core was completely encapsulated by a Li1.15[Ni1/4Mn3/4]0.85O2 shell. The structure and morphology of the as-prepared core–shell structured material were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD results indicate that the core–shell structured material has a typical layered structure with the existence of a Li2MnO3-type integrated component. Spherical morphologies with an inner core and outer shell layer are clearly observed by SEM. A half cell using the core–shell structured cathode material showed a high capacity of 242 mA h g−1 at a rate of 0.1 C in a voltage range of 2.0–4.8 V. Especially, the core–shell structured cathode material represents excellent lithium intercalation stability compared to the Li1.15[Mn1/3Co1/3Mn1/3]0.85O2 core, and an improved rate capability compared to the Li1.15[Ni1/4Mn3/4]0.85O2 shell. A synergetic effect of the positive attributes of the two materials is achieved by the formation of the core–shell architecture. Therefore, the as-prepared core–shell structured Li1.15[(Mn1/3Ni1/3Co1/3)0.5(Ni1/4Mn3/4)0.5]0.85O2 is very effective for improving the electrochemical behavior of Li-rich layered cathode materials in the high-performance lithium ion batteries.

Fe1−xCoxF3 (x = 0, 0.03, 0.05, 0.07) compounds are synthesized via a liquid-phase method. To further improve their electrochemical properties, a ball milling process with acetylene black (AB) has been used to form Fe1−xCoxF3/C (x = 0, 0.03, 0.05, 0.07) nanocomposites. The structure and performance of the samples have been characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray spectroscopy (EDX), charge–discharge tests, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and the galvanostatic intermittent titration technique (GITT). It is found that Co-doping significantly improves the electrochemical performance. Fe0.95Co0.05F3/C exhibits excellent electrochemical performance with discharge capacities of 151.7, 136.4 and 127.6 mA h g−1 at rates of 1C, 2C and 5C in the voltage range of 2.0–4.5 V vs. Li+/Li, and its capacity retentions remain as high as 92.0%, 92.2% and 91.7%, respectively, after 100 cycles. Co-doping could decrease the charge transfer resistance, increase the lithium diffusion coefficient during the lithiation process and improve the electrochemical reversibility. The preparation of Co-doped FeF3/C offers a new method to improve the performance of FeF3: cationic doping, which is a significant step forward for developing high-power lithium batteries.