The optoelectronic performance of hybrid devices from graphene and optically sensitive semiconductors exceeds conventional photodetectors due to a large in-built optical gain. Tellurium nanowire (TeNW), being a narrow direct band gap semiconductor (∼0.65 eV), is as an excellent potential candidate for near infra-red (NIR) detection. Here we demonstrate a new graphene-TeNW binary hybrid that exhibits a maximum photoresponsivity of ∼10 A W at 175 K in the NIR regime (920 nm-1720 nm), which exceeds the photoresponsivity of the most common NIR photodetectors. The resulting noise-equivalent power (NEP) is as low as 2 × 10 W Hz, and the specific detectivity (D*) exceeds 5 × 10 cm Hz W (Jones). The temperature range of optimal operation, which extends up to ≈220 K and ≈260 K for 1720 nm and 920 nm excitation, respectively, is primarily limited by the electrical conductivity of the TeNW layer, and can further be improved by lowering of the defect density as well as inter-wire electronic coupling.

Fe–Fe3C encapsulated Fe–Nx enriched N-doped carbon nanotubes as an air-cathode electrocatalyst for metal–air batteries and their practical feasibility for powering light emitting diodes.

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We report a facile synthesis of Zn2SiO4 nanotubes using a two-step process consisting of a wet-chemical synthesis of core-shell ZnO@SiO2 nanorods followed by thermal annealing. While annealing in air leads to the formation of hollow Zn2SiO4, annealing under reducing atmosphere leads to the formation of SiO2 nanotubes. We rationalize the formation of the silicate phase at temperatures much lower than the temperatures reported in the literature based on the porous nature of the silica shell on the ZnO nanorods. We present results from in situ transmission electron microscopy experiments to clearly show void nucleation at the interface between ZnO and the silica shell and the growth of the silicate phase by the Kirkendall effect. The porous nature of the silica shell is also responsible for the etching of the ZnO leading to the formation of silica nanotubes under reducing conditions. Both the hollow silica and silicate nanotubes exhibit good uranium sorption at different ranges of pH making them possible candidates for nuclear waste management.

We present a novel anode interface modification on the β″-alumina solid-state electrolyte that improves the wetting behavior of molten sodium in battery applications. Heat treating a simple slurry, composed only of water, acetone, carbon black, and lead acetate, formed a porous carbon network decorated with PbO x (0 ≤ x ≤ 2) nanoparticles between 10 and 50 nm. Extensive performance analysis, through impedance spectroscopy and symmetric cycling, shows a stable, low-resistance interface for close to 6000 cycles. Furthermore, an intermediate temperature Na−S cell with a modified β″-alumina solid-state electrolyte could achieve an average stable cycling capacity as high as 509 mA h/g. This modification drastically decreases the amount of Pb content to approximately 3% in the anode interface (6 wt % or 0.4 mol %) and could further eliminate the need for toxic Pb altogether by replacing it with environmentally benign Sn. Overall, in situ reduction of oxide nanoparticles created a high-performance anode interface, further enabling large-scale applications of liquid metal anodes with solid-state electrolytes.

We introduce a new and naturally abundant mild reducing agent, tannic acid, to improve the seed-mediated growth method for the synthesis of elongated tetrahexahedral Au nanocrystals enclosed with high-index (730) planes, at room-temperature. The control of the dimensions, plasmonics and electro-catalysis of such high-index faceted nanocrystals is remarkable.

Phase, morphology, and electrochromicity tailoring in nanoscale WO3.

as future power sources due to their remarkably high theoretical energy output. [1][2][3][4] For instance, Zinc-air batteries are predicted to have a high theoretical specific energy density of 1086 W h kg −1 , which is 2.5 times higher than state-ofthe-art lithium-ion batteries. [5][6][7][8] The key to the functioning of Zn-air batteries is two electrochemical reactions occurring at the air cathode, namely oxygen reduction reaction (ORR) during discharging and oxygen evolution reaction (OER) during charging. Consequently, the inferior performance of the air cathode leads to the Zinc-air batteries displaying lower energy output than the theoretical value. Hence, catalysts with excellent catalytic efficacy towards ORR (e.g., Pt) and OER (e.g., RuO 2 ) are employed in the air cathode to enhance the performance of Zn-air batteries. However, the poor stability, high cost, and scarcity of state-of-the-art catalysts such as Pt or RuO 2 make the technology commercially untenable. Thus, the widespread adoption of Zinc-air batteries depends on discovering low-cost, highly active, stable, and potentially bifunctional electrocatalysts. Recently, transition metal oxide (TMO) systems emerged as viable ORR and OER electro catalysts due to their competentThe enhanced safety, superior energy, and power density of rechargeable metal-air batteries make them ideal energy storage systems for application in energy grids and electric vehicles. However, the absence of a cost-effective and stable bifunctional catalyst that can replace expensive platinum ( Pt)-based catalyst to promote oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) at the air cathode hinders their broader adaptation. Here, it is demonstrated that Tin (Sn) doped β-gallium oxide (β-Ga 2 O 3 ) in the bulk form can efficiently catalyze ORR and OER and, hence, be applied as the cathode in Zn-air batteries. The Sn-doped β-Ga 2 O 3 sample with 15% Sn (Sn x=0.15 -Ga 2 O 3 ) displayed exceptional catalytic activity for a bulk, non-noble metal-based catalyst. When used as a cathode, the excellent electrocatalytic bifunctional activity of Sn x=0.15 -Ga 2 O 3 leads to a prototype Zn-air battery with a high-power density of 138 mW cm −2 and improved cycling stability compared to devices with benchmark Pt-based cathode. The combined experimental and theoretical exploration revealed that the Lewis acid sites in β-Ga 2 O 3 aid in regulating the electron density distribution on the Sn-doped sites, optimize the adsorption energies of reaction intermediates, and facilitate the formation of critical reaction intermediate (O*), leading to enhanced electrocatalytic activity.