Sequential Engineering of Ternary CuFeNi with a Vertically Layered Structure for Efficient and Bifunctional Catalysis of the Oxygen and Hydrogen Evolution Reactions

Abstract

Developing efficient and earth-abundant electrocatalysts for electrochemical water splitting is greatly desired due to growing energy demands. Herein, we develop a promising hierarchical nickel–iron–copper nitride electrode that is fabricated via a three-step process, starting with a hydrothermal synthesis of nickel–iron hydroxide on nickel foam and followed by the direct growth of copper metal–organic frameworks and, finally, low temperature ammonization. This approach yields a material that is an efficient catalyst for both the oxygen evolution reaction and the hydrogen evolution reaction. The as-fabricated heterostructured nickel–iron–copper nitride electrode exhibits an excellent activity with an overpotential of only 121 mV for the oxygen evolution reaction and an even a lower overpotential of 33 mV for the hydrogen evolution reaction. Additionally, this structure displays strong long-term stability with only a negligible increase in potential after 500 cycles of uninterrupted cyclic voltammetry testing. To the best of our knowledge, this as-prepared hierarchical nickel–iron–copper nitride is one of the most promising alternatives for the electrochemical oxygen and hydrogen evolution reactions.

Recent advances in transition metal-based electrocatalysts for alkaline hydrogen evolution

“…Moreover, bimetallic and trimetallic nitrides are recognized to exhibit better abilities than the corresponding single metal nitrides due to the regulated electrical conductivity and the synergy between/among the adjacent heteromatals. 204 The currently reported P-NiMo 4 N 5 , 207 Cu x Ni y Fe 4-x-y N, 204 Cu x Ni 4-x N, FeNi-N, and Ni-Mo-N are identified as highperformance and low-cost catalysts towards alkaline HER.…”

“…201 Ni x N y and Mo x N y are the primary documented catalysts. Commonly, the y/x is less than 1 in TM x N y , such as Ni 3 N, 5,78,79,81 Mo 2 N, 202,203 Cu x Ni y Fe 4-x-y N, 204 and Ni 3 FeN, 205 because incorporation of N atoms into a transition metal lattice is thermodynamically unfavourable. 77 The low valance state of the metal atoms may result in oxidation of TMNs during the electrochemical tests.…”

Defect Engineering of a Mott‐Schottky‐Type Self‐Supporting Electrode for Rechargeable Zinc‐Air Battery

“…Similarly, two peaks of Ni 3 Fe@NiFe 2 O 4 /CP are located at 712.3 eV and 724.6 eV, corresponding to Fe 2p 3/2 and Fe 2p 1/2 respectively (Figure S4E). Figure S4F shows the Ni2p XPS of Ni 3 Fe@NiFe 2 O 4 /CP, of which three components, match well with Ni 2p 3/2 (856.3 eV), Ni 2p 1/2 (874.6 eV) and metal Ni (853.1 eV) [13] …”

“…Figure S4F shows the Ni2p XPS of Ni 3 Fe@NiFe 2 O 4 /CP, of which three components, match well with Ni 2p 3/2 (856.3 eV), Ni 2p 1/2 (874.6 eV) and metal Ni (853.1 eV). [13] The OER and ORR performances of Ni 3 Fe@NiFe 2 O 4 /CP and PtÀ Ni 3 Fe@ NiFe 2 O 4 /CP electrodes were studied via a typical three-electrode system. The self-supporting electrode is equipped into a three-electrode system with O 2 -saturated 0.1 M KOH as an electrolyte.…”

Co–N Active Sites between Co Nanoparticles and N-Doped Carbon toward Remarkably Enhanced Electrocatalytic Oxygen Evolution and Hydrogen Evolution Reactions

“…Recently, a series of bifunctional catalysts have been reported. − Among them, bifunctional transition-metal (TM) catalysts are considered to be the most promising because of their excellent catalytic activities. − However, bifunctional TM catalysts still face problems, such as fewer inherent active sites, inferior conductivity, and poorer stability . Thereby, fixing the active material to the carbon matrix can prevent agglomeration of the active materials and improve stability and conductivity.…”