Abstract Nickel stable isotopes (δ60Ni) provide insight to Ni biogeochemistry in the modern and past oceans. Here, we present the first Pacific Ocean high‐resolution dissolved Ni concentration and δ60Ni data, from the US GEOTRACES GP15 cruise. As in other ocean basins, increases in δ60Ni toward the surface ocean are observed across the entire transect, reflecting preferential biological uptake of light Ni isotopes, however the observed magnitude of fractionation is larger in the tropical Pacific than the North Pacific Subtropical Gyre. Such surface ocean fractionation by phytoplankton should accumulate isotopically lighter Ni in the deep Pacific, yet we find that North Pacific deep ocean δ60Ni is similar to previously reported values from the deep Atlantic. Finally, we find that seawater dissolved δ60Ni in regions with hydrothermal input can be either higher or lower than background deep ocean δ60Ni, depending on vent geochemistry and proximity.
more »
« less
In-situ electrochemical formation of nickel oxyhydroxide (NiOOH) on metallic nickel foam electrode for the direct oxidation of ammonia in aqueous solution
- Award ID(s):
- 1632899
- PAR ID:
- 10091650
- Date Published:
- Journal Name:
- Electrochimica Acta
- Volume:
- 281
- Issue:
- C
- ISSN:
- 0013-4686
- Page Range / eLocation ID:
- 410 to 419
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Supercapacitors and batteries are essential for sustainable energy development. However, the bottleneck is the associated high cost, which limits bulk use of batteries and supercapacitors. In this context, realizing that the cost of energy‐storage device mainly depends on materials, synthesis processes/procedures, and device fabrication, an effort is made to rationally design and develop novel low‐cost electrode materials with enhanced electrochemical performance in asymmetric supercapacitors. Herein, surface functionalization approach is adopted to design low‐cost 3D mesoporous and nanostructured nickel–nickel oxide electrode materials using facile synthesis for application in supercapacitors. It is demonstrated that the 3D mesoporous Ni provides the high surface area and enhanced ionic conductivity, while germanium functionalization improves the electrical conductivity and reduces the charge‐transfer resistance of NiO. Surface functionalization with Ge demonstrates the significant improvement in specific capacitance of NiO. The asymmetric supercapacitor using these Ge‐functionalized NiO–Ni electrodes provides a specific capacitance of 304 Fg−1(94 mF cm−2), energy density of 23.8 Wh kg−1(7.35 μWh cm−2), and power density of 6.8 kW kg−1(2.1 mW cm−2) with excellent cyclic stability of 92% after 10 000 cycles. To validate their practical applications, powering the digital watch using the asymmetric supercapacitors in laboratory conditions is demonstrated.more » « less
An official website of the United States government

