Synergistic Activation of Crystalline Ni₂P and Amorphous NiMoO_x for Efficient Water Splitting at High Current Densities

Abstract

The overpotential of alkaline water electrolysis at high current density is significantly increased by the high energy barriers of high intermediate (H* and OH*) and slow mass/charge transfer. Modifying the electronic structure and morphology of catalysts to decrease energy barriers and enhance mass/charge transfer is a promising approach, but it presents significant challenges. In this study, the crystalline Ni 2 P clusters were coupled with an amorphous NiMoO x nanorod support on a nickel foam substrate (Ni 2 P−NiMoO x /NF) to create a heterojunction that enhances mass/charge transfer, tunes energy barriers, and improves reaction kinetics through synergistic activation. The Ni 2 P− NiMoO x /NF exhibits ultralow overpotentials of 91, 188, and 297 mV at 10, 100, and 500 mA cm −2 , respectively, for the hydrogen evolution reaction, along with stability. It also shows superior performance in the oxygen evolution reaction. Remarkably, the Ni 2 P− NiMoO x /NF-based electrolyzer achieves 100 and 400 mA cm −2 at low cell voltages of 1.66 and 2.08 V, respectively, while also maintaining stable electrolysis for 100 h under industrial testing (65 °C with 30% KOH). Additional characterization and density functional theory calculations demonstrate that the interaction between Ni 2 P and NiMoO x facilitates the downshifting of d-band centers to the Fermi level, which results in the activation of the local electronic structure, promoting H 2 O dissociation and enhancing the overall catalytic activity.

Interfacial Electronic Redistribution via Anionic Modulator for Superb and Highly Stable Water/Seawater Oxidation

“…The peak observed at 133.1 eV corresponds to P–O. The peaks located at 129.1 and 129.8 eV are associated with P 2p 3/2 and P 2p 1/2 , respectively, and correspond to metal-P (M-P) . Raman and Fourier transform infrared (FTIR) spectra were measured to examine the bonding information.…”

“…39−43 The peaks located at 129.1 and 129.8 eV are associated with P 2p 3/2 and P 2p 1/2 , respectively, and correspond to metal-P (M-P). 48 Raman and Fourier transform infrared (FTIR) spectra were measured to examine the bonding information. As shown in Figure S8, the weak Raman peak at 461 cm −1 is assigned to the vibration of Ni 2+ -O in Ni(OH) 2 and broad peak at 674 cm −1 to A 1g stretching modes of NiFe 2 O 4 .…”

FeNi decorated nitrogen-doped hollow carbon spheres as ultra-stable bifunctional oxygen electrocatalyst for rechargeable zinc–air battery with 2.7% decay after 300 hours cycling

“…The clear interface between the FeNi nanoparticles and N–C support suggests that synergistic effect will effectively enhance the electrical conductivity. 12,38 In Fig. 3(d), the high-resolution TEM image indicates that cubic FeNi phase, respectively.…”

“…Over the past decade, many efforts have been devoted to develop non-noble metal bifunctional electrocatalysts, such as oxides, 11–14 transition metals and their alloys, 15–18 sulphides, 19 nitrides, 20,21 and various carbon materials. 22,23 Among these, the transition metal–nitrogen/carbon compound often exhibited excellent electrocatalytic activity and long-term stability for OER/ORR.…”

CoOx-NCNT-Supported NiFe-Selenide Nanosheets as an Efficient Bifunctional Electrocatalyst for Water Splitting

“…The higher proton concentration accelerates the reaction rate, contributing to improved performance. However, conducting both reactions (OER and HER) in alkaline conditions is often more beneficial for the development of bifunctional electrocatalysts, particularly for practical applications like water electrolysis. , Comparative analysis of NiFeSe@CoOx-NCNTs for OER and HER activities with the materials reported in the literature is depicted in Figure , which includes NiFeSe@CoOx-NCNTs (our work), Mo–Ni–Se@NF, NiCoSe 2– x /NC, Cu-(a-NiSe x /c-NiSe 2 )/TiO 2 NRs, Fe 0.08 Ni 0.77 Se/CNT 3, Fe-doped NiSeNSs/CNTs, CoPSe–CoSe 2 /CNTs, Ni 0.85 Se/RGO/CNTs, NiCo­(Sn)­Se, Co–Fe Selenide, and Fe 2 O 3 –CoSe 2 @Se/CC …”