The metallic dopants in palladium (Pd) sensing materials enable modification of the d-band center of Pd, which is expected to tune the α–β phase transitions of the PdH x intermediate, thus improve the sensing stability to hydrogen. Here, the boosted hydrogen-sensing stability at ultra-low temperatures has been achieved with palladium/cobalt nanowires (PdCo NWs) as the sensing material. The various Co contents in PdCo NWs were modulated via AAO-template-confined electrodeposition. The temperature-dependent sensing evaluations were performed in 0.1–3 v/v% hydrogen. Such sensors integrated with PdCo NWs are able to stably detect hydrogen as low as 0.1 v/v%, even when the temperature is lowered to 273 K. In addition, the critical temperatures of “reverse sensing behavior” of the PdCo NWs (Pd 82 Co 18 : T c = 194 K; Pd 63 Co 37 : T c = 180 K; Pd 33 Co 67 : T c = 184 K) are observed much lower than that of pristine Pd NWs ( T c = 287 K). Specifically, the Pd 63 Co 37 NWs (∼37 at% Co content) sensor shows outstanding stability of sensing hydrogen against α–β phase transitions within the wide temperature range of 180–388 K, which is attributed to both the electronic interactions between Pd and Co and the lattice compression strain caused by Co dopants. Moreover, the “reverse sensing behavior” of the PdCo NWs is explicitly interpreted using the α–β phase transition model.
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Synthesis of flexible Co nanowires from bulk precursors
This work reports a method of producing flexible cobalt nanowires (NWs) directly from the chemical conversion of bulk precursors at room temperature. Chemical reduction of Li 6 CoCl 8 produces a nanocomposite of Co and LiCl, of which the salt is subsequently removed. The dilute concentration of Co in the precursor combined with the anisotropic crystal structure of the hcp phase leads to 1D growth in the absence of any templates or additives. The Co NWs are shown to have high saturation magnetization (130.6 emu g −1 ). Our understanding of the NW formation mechanism points to new directions of scalable nanostructure generation.
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- Award ID(s):
- 1922639
- PAR ID:
- 10460900
- Date Published:
- Journal Name:
- RSC Advances
- Volume:
- 12
- Issue:
- 33
- ISSN:
- 2046-2069
- Page Range / eLocation ID:
- 21153 to 21159
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/d2ra03790d
