Suppressed Jahn–Teller Distortion in MnCo₂O₄@Ni₂P Heterostructures to Promote the Overall Water Splitting

Abstract

Jahn–Teller distortion in cobalt based spinel electrocatalysts causes poor activity and stability in potentially promising catalysts for water splitting. Here, a novel strategy to resolve this problem by interface engineering is reported, in which, Jahn–Teller distortion in MnCo2O4 is significantly suppressed by in situ growth Ni2P nanosheets onto the MnCo2O4. The significance of interface engineering in suppressing Jahn–Teller distortion of Mn3+ is further investigated by X‐ray photoelectron spectroscopy, the resulting increased catalytic activity and the effects of suppressed distortion demonstrated by density functional theory calculations. The resulting MnCo2O4@Ni2P heterostructures exhibit superior electrocatalytic activity for the both oxygen evolution reaction and hydrogen evolution reaction with small overpotentials of 240 and 57 mV at 10 mA cm‐2, respectively. Furthermore, the heterogeneous composite electrode demonstrates a superior current density of 10 mA cm‐2 at a voltage of 1.63 V with excellent durability in a water splitting cell.

Porous rod-like Ni2P/Ni assemblies for enhanced urea electrooxidation

“…Additionally, the intrinsic coordination of divalent Ni to -O and C-O is a driving force for the activation of the urea molecules. 6NiOOH + CO(NH2)2 + H2O → 6Ni(OH)2 + N2 + CO2 (5) As seen in the model, the surface of the molecule has more Ni 2+ in the active sites of the reaction, which plays a key role in UOR. Moreover, the uniform distribution of nickel nanoparticles yields high conductivity and promotes the absorption of gas products, reducing the adsorption energy of OHduring the whole process.…”

“…A growing number of studies suggest that, for efficient electrolysis in alkaline solutions, nickel-based materials have great potential to replace precious metals (such as Pt, Rh, Au, etc. ), which are outstanding electrode materials in electrocatalysis, though suffering from high cost and their scarcity [1][2][3][4][5][6][7][8]. Notably, it is still a great challenge to develop the electroactive sites, reactivity, and stability of the electrocatalytic materials for their full usage [9][10][11][12][13][14].…”

Atomic Heterointerface Engineering of Ni2P‐NiSe2 Nanosheets Coupled ZnP‐Based Arrays for High‐Efficiency Solar‐Assisted Water Splitting

“…Such results are assumed by the unique architecture of the ZnP@Ni 2 P‐NiSe 2 material with highly open channels that can effectively avoid the massive accumulation of bubbles and quickly discharge them from the active surface of the catalyst. By comparing with the recently reported bifunctional catalysts, the ZnP@Ni 2 P‐NiSe 2(+,‐) is one of the best devices for alkaline water splitting (Figure 4i), [ 38,52–74 ] demonstrating the noble metal‐free ZnP@Ni 2 P‐NiSe 2 heterostructured electrocatalyst is an effective and stable candidate for the overall water splitting to produce the green hydrogen.…”

1D Nanowire Heterojunction Electrocatalysts of MnCo2O4/GDY for Efficient Overall Water Splitting

“…23-1237, space group: Fd3m). [22] The characteristic peaks at 2θ = 18.3°, 30.6°, 36.2°, 44.1°, 54.8°, 58.6°, and 64.4° correspond to the (111), ( 220), (311), (400), ( 422 4b). Compared with pure GDY, the emergence π-π* transition peak at 290.2 eV implies the restoration of the delocalized π conjugation, which reveals the interaction between MnCo 2 O 4 and GDY.…”

“…[17] Among them, spinel structure metals oxides (e.g., Co 3 O 4 , MnCo 2 O 4 , CoFe 2 O 4 , NiCo 2 O 4 ) have shown many advantages, such as low-cost, abundance, rich in multivalent states, and function to electrochemical redox reactions. [16,[18][19][20][21][22][23][24] However, their performances are still far from satisfactory. Therefore, the development of catalytic materials with new chemical structures and tunable electronic structures is an effective method to solve these issues.…”