Palladium/cobalt nanowires with improved hydrogen sensing stability at ultra-low temperatures. Issue 44 (5th November 2019)

• Record Type: Journal Article
• Authors: Du, Lingling; Feng, Dongliang; Xing, Xiaxia; Fu, Yang; Fonseca, Luis F.; Yang, Dachi
• Is Part Of: Nanoscale. Volume 11:Issue 44(2019)
• Page Start: 21074
• Page End: 21080
• Publication Date: 2019-11-05
• Subjects: Nanoscience -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/c9nr07834g
• Languages: English
• ISSNs: 2040-3364

Abstract

Abstract : The advanced PdCo NW sensors developed for the detection of hydrogen at a wide temperature range showed excellent low-temperature stability. Abstract : 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 (Pd82 Co18 : T c = 194 K; Pd63 Co37 : T c = 180 K; Pd33 Co67 : T c = 184 K) are observed much lower than that of pristine Pd NWs ( T c = 287 K). Specifically, the Pd63 Co37 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.