Highly durable core(Nb4N5)–shell(NbO )-structured non-precious metal catalyst for oxygen reduction reaction in acidic media

Rohib, R.; Lee, Eunjik; Kim, Changki; Lee, Hyunjoon; Park, Gu-Gon

doi:10.1016/j.jallcom.2022.167882

Cited by 3 publications

(4 citation statements)

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“…To the best of our knowledge, this is the first work to employ this morphology obtained by hydrothermal synthesis (HS), with and without annealing (HT), in dissolved oxygen sensing. In addition, this is one of the few works to report the performance of the obtained oxides along a wide pH range (2.5-11) [17]. This work also provides insights into the formation of acidic niobium oxide structures as intermediates in niobium oxide crystal formation, as well as the consumption of acidic functions in the ORR.…”

Section: Introductionmentioning

confidence: 77%

“…Other authors used an alumina template to obtain columnar niobium oxide nanostructures [15,16]. Nb 2 O 5 nanoparticles have been synthesized via laser ablation for further heat treatment to obtain niobium nitrides [17].…”

Section: Introductionmentioning

confidence: 99%

“…Most of the works reported in the literature employ niobium oxide as a support for tuning the selectivity and avoiding the poisoning of catalysts [20]. However, its capability has been demonstrated to catalyze fundamental reactions, such as oxygen reduction [17,21]. Compared with Pt, niobium oxides have not received much attention as catalysts for ORR; however, they have been employed as catalyst supports, with promising results [20,22,23], or as co-catalysts [24].…”

Section: Introductionmentioning

confidence: 99%

“…Compared with Pt, niobium oxides have not received much attention as catalysts for ORR; however, they have been employed as catalyst supports, with promising results [20,22,23], or as co-catalysts [24]. In the work of Rohib et al [17], the authors reported the synthesis of an Nb 4 N 5 -NbO x core-shell structure that catalyzed ORR in acidic medium. Other researchers [25] pointed out the need for heat treatment in a reducing atmosphere for enhancing the ORR electrocatalytic performance due to the distribution of defects.…”

Section: Introductionmentioning

confidence: 99%

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Niobium Oxide Nanorods Obtained by Hydrothermal Synthesis—Structure, Morphology, and Electrochemical Detection of Oxygen Via Oxygen Reduction Reaction

Vega,

Consul,

Cadorin

et al. 2023

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Niobium oxides are promising materials for applications within various research fields, especially as electrocatalysts for various chemical reactions. The tuning of the synthetic parameters can achieve a successful compromise between morphology and structure, aiming to obtain certain properties. Hence, this study aimed to investigate the influence of hydrothermal synthesis parameters on the morphology and structure of niobium oxide growth on a niobium metallic plate. The effect of annealing on the material performance was also evaluated. Afterward, the most crystalline sample was tested for the electrochemical determination of dissolved oxygen, a fundamental reaction in corrosion, biomedicine, and environmental monitoring. This is the first work using this material configuration as an electrochemical sensor. The hydrothermal synthesis produced nanorods formed by poorly crystalline, acidic, hydrated Nb2O5. Increasing the mineralizer concentration could increase the crystallinity and the nanorod growth rate, but it could also promote a lack of structural and morphological uniformity throughout the surface. Heat treatment allowed the increase in crystallinity and favored orthorhombic Nb2O5. Raman spectroscopy revealed that, at the first moment, acidic, hydrated niobium oxide structures were formed as precursors of crystalline niobium oxide that would be developed with longer reaction times and a higher mineralizer concentration. The obtained niobium oxide showed electrocatalytic activity toward the oxygen reduction reaction, with comparable performance between the samples with and without heat treatment. At all analyzed pH values, the amperometric response was linearly correlated with the dissolved oxygen concentration. pH influenced the sensitivity of the material; a maximum sensitivity of 0.0417 mA/cm2·mg/L O2 was achieved at pH = 6. The participation of the acidic functionalities of the surface in the ORR reaction was confirmed by Raman spectroscopy.

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Section: Introductionmentioning

confidence: 77%