Ni₃FeN Nanoparticles Derived from Ultrathin NiFe‐Layered Double Hydroxide Nanosheets: An Efficient Overall Water Splitting Electrocatalyst

Abstract

Mo 2 C, [ 5 ] MoB, [ 5 a] NiMoN x , [ 6 ] and Co 0.6 Mo 1.4 N 2 , [ 7 ] whereas for OER-layered double hydroxides (LDHs) containing nickle, [ 8 ] cobalt, [ 8 b, 9 ] and iron [ 8 a, c, 10 ] or their calcination-derived mixed metal oxide (MMO) nanocomposites show good and stable activities. [ 11 ] However, the majority of these electrocatalysts are either semiconducting or insulating, which greatly hinders electron transfer from the electrocatalyst to the support electrode, thereby restricting their overall effi ciency and utilization potential. Using a single bifunctional OER and HER catalyst can simplify the water splitting system and also lowers the cost. [ 12 ] However, this is challenging since the same material must be able to effectively catalyze both the OER and HER while achieving a low overall overpotential and as high a current density as possible. [ 13 ] Compared to oxides and hydroxides of a particular metal, metal nitrides often display superior water-splitting activities owing to their special properties such as low electrical resistance and good corrosion resistance. [ 14 ] Recently, the synthesis of Ni 3 N nanosheets was reported for the fi rst time, [ 15 ] which potentially could represent a new class of OER electrocatalyst with better properties than NiO. Compared with single-metal nitrides, the activity of double metal nitrides can more readily be optimized through a controlled manipulation of the valence and electronic states of the metal elements, resulting in enhanced water-splitting performance. [ 7 ] LDHs are a family of layered clays containing divalent and trivalent metal cations, which can include electrochemically active elements such as Ni, Fe, and Co amongst others. [ 16 ] LDH nanosheets with ultrathin atomic scale thickness can readily be synthesized using top-down or bottom-up approaches. [ 17 ] Thermal ammonolysis of LDH nanosheets could potentially lead to the formation of novel nanostructured mixed metal nitrides (MMNs) for electrocatalytic applications, though very little work has been conducted in this area to date. The viability of this approach for the rational design of nanostructured MMNs from LDH precursors for overall water splitting is systematically explored herein.In this work, Ni 3 FeN nanoparticles (Ni 3 FeN-NPs) with a particle size of 100 nm and a thickness of ≈9 nm are successfully synthesized by thermal ammonolysis of ultrathin NiFe-LDH nanosheets prepared using a reverse microemulsion method ( Scheme 1 ). The Ni 3 FeN-NPs exhibited extraordinarily high activities for both HER and OER with low overpotentials of 158 and 280 mV at 10 mA cm −2 , respectively, and Tafel slopes of 42 and 46 mV dec −1 , respectively. The remarkable electrocatalytic activity of Ni 3 FeN-NPs can be attributed to highly exposed active sites and high electrical conductivity. This work conclusively Demand for clean renewable energy will increase enormously over the next 50-100 years, driven by rapid human population growth, fast depletion of fossil fuel resources, and environmental ...

Promoting charge carrier utilization by integrating layered double hydroxide nanosheet arrays with porous BiVO4 photoanode for efficient photoelectrochemical water splitting

“…This suggests that the morphology of the NiFe-LDH could be tuned by varying the content of Ni 2+ . In addition, the actual Ni/Fe molar ratio in the LDHs measured by the EDX and ICP is different from the initial molar ratio of Ni 2+ and Fe 3+ , which is attributed to that one of metal cations is preferentially incorporated into the LDH nanosheets during the formation of LDHs [51,52]. The PEC performances of the above composite photoanodes were evaluated by LSV curves (Fig.…”

Cobalt-vanadium bimetal-based nanoplates for efficient overall water splitting

“…The materials based on early and late transition metals (ETMs and LTMs) are promising for HER and OER [14,15], such as the transition metals sulfides [16,17], phosphides [18][19][20][21][22], selenide [23], nitride [24][25][26] and carbides [27] for HER, and oxides (Ni oxides [28,29] and Co oxides [30][31][32]) for OER. The cobalt (Co), as a typical LTM, is promising in HER due to its relatively low cost and the activity for the reduction of H + [33].…”

In situ hybridization of an MXene/TiO2/NiFeCo-layered double hydroxide composite for electrochemical and photoelectrochemical oxygen evolution

“…, Fe 3+ and Co 2+ precursors as well as Ti 3 C 2 T x in a reverse microemulsion system, 44,51 in which N,N-dimethyltetradecylamine and n-butanol were mixed with a volume ratio of 8 : 5. The surface-terminated groups (i.e.…”