While electrochemical water splitting is one of the most promising methods to store light/electrical energy in chemical bonds, a key challenge remains in the realization of an efficient oxygen evolution reaction catalyst with large surface area, good electrical conductivity, high catalytic properties, and low fabrication cost. Here, a facile solution reduction method is demonstrated for mesoporous Co3O4 nanowires treated with NaBH4. The high‐surface‐area mesopore feature leads to efficient surface reduction in solution at room temperature, which allows for retention of the nanowire morphology and 1D charge transport behavior, while at the same time substantially increasing the oxygen vacancies on the nanowire surface. Compared to pristine Co3O4 nanowires, the reduced Co3O4 nanowires exhibit a much larger current of 13.1 mA cm‐2 at 1.65 V vs reversible hydrogen electrode (RHE) and a much lower onset potential of 1.52 V vs RHE. Electrochemical supercapacitors based on the reduced Co3O4 nanowires also show a much improved capacitance of 978 F g‐1 and reduced charge transfer resistance. Density‐functional theory calculations reveal that the existence of oxygen vacancies leads to the formation of new gap states in which the electrons previously associated with the Co‐O bonds tend to be delocalized, resulting in the much higher electrical conductivity and electrocatalytic activity.

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A homologous Ni–Co based nanowire system, consisting of both nickel cobalt oxide and nickel cobalt sulfide nanowires, is developed for efficient, complementary water splitting. The spinel‐type nickel cobalt oxide (NiCo2O4) nanowires are hydrothermally synthesized and can serve as an excellent oxygen evolution reaction catalyst. Subsequent sulfurization of the NiCo2O4 nanowires leads to the formation of pyrite‐type nickel cobalt sulfide (Ni0.33Co0.67S2) nanowires. Due to the 1D nanowire morphology and enhanced charge transport capability, the Ni0.33Co0.67S2 nanowires function as an efficient, stable, and robust nonnoble metal electrocatalyst for hydrogen evolution reaction (HER), substantially exceeding CoS2 or NiS2 nanostructures synthesized under similar methods. The Ni0.33Co0.67S2 nanowires exhibit low onset potential of −65, −39, and −50 mV versus reversible hydrogen electrode, Tafel slopes of 44, 68, and 118 mV dec−1 at acidic, neutral, and basic conditions, respectively, and excellent stability, comparable to the best reported non‐noble metal‐based HER catalysts. Furthermore, the homologous Ni0.33Co0.67S2 nanowires and NiCo2O4 nanowires are assembled into an all‐nanowire based water splitting electrolyzer with a current density of 5 mA cm−2 at a voltage as 1.65 V, thus suggesting a unique homologous, earth abundant material system for water splitting.

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A novel natural rubber/silica (NR/SiO 2 ) nanocomposite is developed by combining self-assembly and latex-compounding techniques. The results show that the SiO 2 nanoparticles are homogenously distributed throughout NR matrix as nano-clusters with an average size ranged from 60 to 150 nm when the SiO 2 loading is less than 6.5 wt%. At low SiO 2 contents (64.0 wt%), the NR latex (NRL) and SiO 2 particles are assembled as a core-shell structure by employing poly (diallyldimethylammonium chloride) (PDDA) as an inter-medium, and only primary aggregations of SiO 2 are observed. When more SiO 2 is loaded, secondary aggregations of SiO 2 nanoparticles are gradually generated, and the size of SiO 2 cluster dramatically increases. The thermal/thermooxidative resistance and mechanical properties of NR/SiO 2 nanocomposites are compared to the NR host. The nanocomposites, particularly when the SiO 2 nanoparticles are uniformly dispersed, possess significantly enhanced thermal resistance and mechanical properties, which are strongly depended on the morphology of nanocomposites. The NR/SiO 2 has great potential to manufacture medical protective products with high performances.

We developed a postgrowth doping method of TiO2 nanowire arrays by a simultaneous hydrothermal etching and doping in a weakly alkaline condition. The obtained tungsten-doped TiO2 core-shell nanowires have an amorphous shell with a rough surface, in which W species are incorporated into the amorphous TiO2 shell during this simultaneous etching/regrowth step for the optimization of photoelectrochemical performance. Photoanodes made of these W-doped TiO2 core-shell nanowires show a much enhanced photocurrent density of ~1.53 mA/cm(2) at 0.23 V vs Ag/AgCl (1.23 V vs reversible hydrogen electrode), almost 225% of that of the pristine TiO2 nanowire photoanodes. The electrochemical impedance spectroscopy measurement and the density functional theory calculation demonstrate that the substantially improved performance of the dual W-doped and etched TiO2 nanowires is attributed to the enhancement of charge transfer and the increase of charge carrier density, resulting from the combination effect of etching and W-doping. This unconventional, simultaneous etching and doping of pregrown nanowires is facile and takes place under moderate conditions, and it may be extended for other dopants and host materials with increased photoelectrochemical performances.

We report an all-nanowire based flexible Li-ion battery full cell, using homologous Mn2O3 and LiMn2O4 nanowires for anodes and cathodes, respectively. The same precursors, MnOOH nanowires, are transformed from hydrothermally grown MnO2 nanoflakes and directly attached on Ti foils via reaction with poly(vinyl pyrrolidone). The Mn2O3 anode and LiMn2O4 cathode are subsequently formed by thermal annealing and reaction with lithium salt, respectively. The one-dimensional nanowire structures provide short lithium-ion diffusion path, good charge transport, and volume flexibility for Li(+) intercalation/deintercalation, thus leading to good rate capability and cycling performance. As proof-of-concept, the Mn2O3 nanowire anode delivers an initial discharge capacity of 815.9 mA h g(-1) at 100 mA g(-1) and maintains a capacity of 502.3 mA h g(-1) after 100 cycles. The LiMn2O4 nanowire cathodes show a reversible capacity of 94.7 mA h g(-1) at 100 mA g(-1) and high capacity retention of ∼ 96% after 100 cycles. Furthermore, a flexible Mn2O3//LiMn2O4 lithium ion full cell is fabricated, with an output voltage of >3 V, low thickness of 0.3 mm, high flexibility, and a specific capacity of 99 mA h g(-1) based on the total weight of the cathode material. It also exhibits good cycling stability with a capacity of ∼ 80 mA h g(-1) after 40 charge/discharge cycles.