Anhui Normal University

About: Anhui Normal University is a education organization based out in Wuhu, China. It is known for research contribution in the topics: Catalysis & Population. The organization has 7955 authors who have published 7309 publications receiving 117443 citations.

Formation of single-crystal tellurium nanowires and nanotubes via hydrothermal recrystallization and their gas sensing properties at room temperature

Abstract: Single-crystal tellurium nanowires and nanotubes were selectively synthesized from tellurium powder through a hydrothermal recrystallization route. The nanowires have an average diameter of 40 nm and lengths of several micrometers, while the nanotubes have diameters of 100–200 nm and lengths of 1–2 µm. The morphologies of the as-obtained tellurium nanocrystals could be controlled by tuning the amount of hydrochloric acid added in the hydrazine hydrate solution. The experimental results demonstrated that tellurium powder could be dissolved and recrystallized in hydrazine hydrate solution under hydrothermal conditions. A dissolution–recrystallization mechanism was proposed for the conversion from tellurium powder to tellurium nanowires or nanotubes. The gas sensing properties of as-synthesized tellurium nanowires and nanotubes were investigated in detail, which revealed that the as-prepared tellurium nanowires and nanotubes, especially the tellurium nanowires, exhibited excellent sensitivity to NH3 at room temperature. The response times of the tellurium nanowires and nanotubes were 5 s and 18 s, and the recovery times were 720 s and 170 s, respectively, which are shorter than those reported for tellurium films. The as-prepared tellurium nanostructures could have potential applications in nanosensors.

Hierarchical NiCo2O4@NiCo2S4 Nanocomposite on Ni Foam as an Electrode for Hybrid Supercapacitors

Abstract: In this work, NiCo2O4@NiCo2S4 nanocomposite with a hierarchical structure is prepared by a multistep process. First, NiCo2O4 nanowires array on Ni foam is prepared by a hydrothermal and a subsequent calcination process. Then, the NiCo2O4 nanowires array is converted to NiCo2O4@NiCo2S4 nanocomposite through a vapor-phase hydrothermal process. The NiCo2O4@NiCo2S4/Ni foam electrode exhibits a specific capacitance of 1872 F g-1 at 1 A g-1, a capacitance retention of 70.5% at 10 A g-1, and a retention ratio of 65% after 4000 charge-discharge cycles. The capacitance of NiCo2O4@NiCo2S4 nanocomposite is much higher than that of the NiCo2O4 nanowires array. The excellent electrochemical capacitive performances of the NiCo2O4@NiCo2S4 nanocomposite can be attributed to the hierarchical nanostructure, which can provide large surface areas and short diffusion pathways for electrons and ions. By using the NiCo2O4@NiCo2S4/Ni foam as the positive electrode and activated carbon/Ni foam as the negative electrode, a hybrid supercapacitor device is fabricated. The device achieves an energy density of 35.6 W h kg-1 and a power density of 1.5 kW kg-1 at 2 A g-1.

Aqueous CO 2 Reduction with High Efficiency Using α-Co(OH) 2 -Supported Atomic Ir Electrocatalysts.

Abstract: Electrochemical reduction of CO2 into energy-dense chemical feedstock and fuels provides an attractive pathway to sustainable energy storage and artificial carbon cycle. Herein, we report the first work to use atomic Ir electrocatalyst for CO2 reduction. By using α-Co(OH)2 as the support, the faradaic efficiency of CO could reach 97.6 % with a turnover frequency (TOF) of 38290 h-1 in aqueous electrolyte, which is the highest TOF up to date. The electrochemical active area is 23.4-times higher than Ir nanoparticles (2 nm), which is highly conductive and favors electron transfer from CO2 to its radical anion (CO2.- ). Moreover, the more efficient stabilization of CO2.- intermediate and easy charge transfer makes the atomic Ir electrocatalyst facilitate CO production. Hence, α-Co(OH)2 -supported atomic Ir electrocatalysts show enhanced CO2 activity and stability.