MOF-Derived Formation of Ni₂P–CoP Bimetallic Phosphides with Strong Interfacial Effect toward Electrocatalytic Water Splitting

Abstract

Bimetallic phosphides have attracted research interest for their synergistic effect and superior electrocatalytic activities for electrocatalytic water splitting. Herein, a MOF-derived phosphorization approach was developed to produce NiP-CoP bimetallic phosphides as bifunctional electrocatalysts for both hydrogen and oxygen evolution reactions (HER and OER). NiP-CoP shows superior electrocatalytic activities to both pure NiP and CoP toward HER and OER, revealing a strong synergistic effect. High-resolution transmission electron microscopy and energy dispersive X-ray spectroscopy elemental mapping analysis show that, in the sample NiP-CoP, the NiP and CoP nanoparticles with an average particle size 10-20 nm were mixed closely on the nanoscale, creating numerous NiP/CoP interfaces. By comparison with the sample NiP+CoP, in which seldom NiP/CoP interfaces exist, we documented that the NiP/CoP interface is an essential prerequisite to realize the synergistic effect and to achieve the enhanced electrocatalytic activities in NiP-CoP bimetallic phosphides. This finding is meaningful for designing and developing bicomponent and even multicomponent electrocatalysts.

Metal–Organic Framework Based Catalysts for Hydrogen Evolution

“…[65] Sun et al reported a gadolinium-based MOF [Gd 2 (abtc)(H 2 O) (OH) 2 ]·2H 2 O (H 4 abtc = 3,3′,5,5′-azobenzene tetracarboxylic acid) for photocatalytic HER. In this case, benzenedicarboxylic acid is applied as the organic ligand to link Ni and Co atoms.…”

“…Apart from ZIF-67, other Co-based MOFs, [67,[118][119][120] ZIF-8, [121] MOF-74, [53,122] Ni 2 (bdc) 2 ted (bdc = 1,4-benzenedicarboxylic acid; ted = triethylenediamine), [123] other Ni-based MOFs [124] and bimetallic MOFs (such as NiZn-MOF (ted as organic linkers), [125] NiFe-MOF (bdc as organic linkers), [126] NiCo-MOF (bdc as organic linkers) [65] ) are demonstrated as effective precursors for the fabrication of various interesting metal compounds and metal/ carbon composites for electrocatalytic water splitting. …”

“…In this case, benzenedicarboxylic acid is applied as the organic ligand to link Ni and Co atoms. [65] Sun et al reported a gadolinium-based MOF [Gd 2 (abtc)(H 2 O) (OH) 2 ]·2H 2 O (H 4 abtc = 3,3′,5,5′-azobenzene tetracarboxylic acid) for photocatalytic HER. [66] The choice of azo-carboxylic acid is attributed to its dye-like characteristics, which aims to introduce a light harvesting unit into MOFs and thus improves the overall catalytic performance.…”

Isostructural NiII Metal–Organic Frameworks (MOFs) for Efficient Electrocatalysis of Oxygen Evolution Reaction and for Gas Sorption Properties

“…[3] Therefore, there is high demandf or an efficient electrocatalyst which can increase the rate of OER at lower overpotential. [8][9][10][11] Amongt he TMOs, cobalt-based spinel oxides have been shown as outstanding OER electrocatalysts. [4,5] However,t heir scarcity,i nferior durability and excessive cost, limit their use in large-scale industrial applications.…”

Ionic Liquid Originated Synthesis of N,P‐doped Graphene for Hydrogen Evolution Reaction

“…Therefore, a low cost and high efficient electrocatalyst for hydrogen evolution reaction (HER) is highly desired to decrease the overpotential and improve the electrolysis rate. Although Nobel metal‐based materials (e. g. Pt‐group metals) are the most frequently used HER catalysts due to their low overpotentials and high current densities, the high cost and scarce abundant have limited their widespread application . Recently, non‐noble metal based HER electrocatalysts, such as Mo 2 C, Co,N‐doped CNTs,, α‐MoB 2 and Co 9 S 8 ,, were prepared to address these issues with good HER activites while some of these materials could lose the catalytic activities during HER conditions and cause the detrimental environmental effects.…”