Spinel nickel ferrite nanoparticles strongly cross-linked with multiwalled carbon nanotubes as a bi-efficient electrocatalyst for oxygen reduction and oxygen evolution

Abstract

It is of great concern to explore new electrocatalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). In this study, spinel NiFe2O4 nanoparticles cross-linked with the outer walls of multiwalled carbon nanotube (MWCNT) were successfully prepared by a peaceable, scalable hydrothermal method. The as-synthesized NiFe2O4/MWCNT nanohybrid shows not only a better ORR catalytic activity than pure NiFe2O4 and MWCNT, but also a close four-electron reaction pathway. Meanwhile, NiFe2O4/MWCNT nanohybrid exhibits much higher OER catalytic activity as compared to NiFe2O4, MWCNT and the commercial Pt/C in terms of the onset potential and current density. Moreover, the NiFe2O4/MWCNT nanohybrid demonstrates the preeminent long-term durability measured by the current-time chronoamperometric test for both ORR and OER, which evidently outperforms the commercial Pt/C. The excellent bifunctional electrocatalytic activities of NiFe2O4/MWCNT nanohybrid are attributed to the strong coupling between NiFe2O4 nanoparticles and MWCNT as well as the network structure. Fig. 3 (a, b) TEM images of NiFe2O4/MWCNT nanohybrid with different magnifications, (c) high-resolution TEM image of NiFe2O4/MWCNT nanohybrid, and (d) enlarged part of the selected area in panel (c).

A review of transition metal‐based bifunctional oxygen electrocatalysts

“…Highly crystalline NiFe oxides can be formed through the high‐temperature annealing of NiFe alloy, in which the ratio of the two metals and the multivalence state of the metals (Ni 2+ /Ni 3+ and Fe 2+ /Fe 3+ ) in NiFe 2 O 4 spinel materials are major factors determining OER activity . In addition, NiFe 2 O 4 has also been reported to demonstrate good OER catalytic activity due to factors such as the outstanding OER activity of Ni‐based oxides and the role of Fe in tuning the electronic structure of NiO x compounds. Moreover, the introduction of conductive substrates into NiFe 2 O 4 can also reportedly improve electrochemical performances through the increase of electronic conductivity.…”

Aerogel Architectures Boost Oxygen‐Evolution Performance of NiFe2Ox Spinels to Activity Levels Commensurate with Nickel‐Rich Oxides

“…[4] The complexitieso ft his four-electron oxidation lead to slow electrode kinetics that require large overpotentials, an energetic penaltyt hat ultimately limits device efficiency and contributes to the corrosion of electrode materials during OER. [5][6][7] Platinum-group oxides, such as RuO 2 andI rO 2 ,p rovide the highest electrocatalytic OER activity in alkaline media to date, [7][8][9] but ar ecent focus on earth-abundant first-row transition-metal oxides, [10][11][12][13][14][15][16][17][18][19][20][21] and some perovskites based on rare-earth, alkaline-earth, and transition metals, [22][23][24] found them to be promising alternative electrocatalysts that offer greater stability.…”

Suppressing Electromagnetic Radiation by Trapping Ferrite Nanoparticles and Carbon Nanotubes in Hierarchical Nanoporous Structures Designed by Crystallization‐Induced Phase Separation

“…The peaks centred at a binding energy of 855.2 and 873.4 eV correspond to Ni 2p 3/2 and Ni 2p 1/2 , respectively. The remaining 2 peaks at around 862.2 and 879.7 are two satellite peaks of Ni at the high binding energy side of the Ni 2p 3/2 and Ni 2p 1/2 , respectively . These peaks (main peaks and satellite peaks) suggests the presence of Ni 2+ cations in NiFe 2 O 4 nanoparticles.…”