Synergistically Coupling of Manganese-Doped CoP Nanowires Arrays with Highly Dispersed Ni(PO₃)₂ Nanoclusters toward Efficient Overall Water Splitting

Abstract

Co-based phosphides are considered to be highly promising electrocatalysts for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). However, their electrocatalytic efficiencies are greatly limited by the weak water dissociation process and unsatisfactory adsorption ability toward reaction intermediates. Herein, novel Mn-doped CoP/Ni­(PO3)2 heterostructure array electrocatalysts which are composed of highly dispersed Ni­(PO3)2 nanoclusters that are tightly wrapped on Mn-doped CoP nanowire arrays are designed. An electrocatalytic performance test suggested that the heterostructure arrays exhibited competitive electrocatalytic performance toward both HER and OER, which needed overpotentials of 116 and 245 mV to drive a current of 10 mA/cm2, respectively. Encouragingly, a symmetric two electrode water splitting system constructed by the heterostructure arrays required an ultralow cell voltage, suggesting the potential in overall water splitting. First-principles calculations combined with experimental characterization were further performed to clarify the electrocatalytic mechanism. On the one hand, effective doping of Mn atoms could optimize the surface electronic structure of CoP and promote the intrinsic activity. On the other hand, the compact and abundant heterogeneous interface between Ni­(PO3)2 and CoP not only made more active sites exposed but also promoted the effective adsorption of intermediate reaction species on the catalyst surface. This work provides a new strategy to improve electrocatalytic performance of Co-based phosphides through the synergistic coupling of metal-doping and phosphate surface decoration, which will greatly promote the development of highly efficient electrocatalysts for overall water splitting.

NiO/Co2P Nanosheets with Heterogeneous Structure as a Multifunctional Catalyst for Overall Water Splitting

“…The binding energy of the main peak of Ni 2p 3/2 was located at 875 eV and the satellite peak was at 880.5 eV, proving the presence of Ni 2+ . 37 In Co 2p spectra of NiO/Co 2 P NSs (Fig. 4d), the peaks at 778.6 and 793.3 eV were ascribed to Co 2p 3/2 and Co 2p 1/2 of Co 3+ , while the peaks at 782.1 and 798.2 eV were Co 2p 3/2 and Co 2p 1/2 of Co 2+ , and two characteristic peaks at binding energies of 786.4 and 803.0 eV were satellite peaks.…”

Recent advances of transition‐metal metaphosphates for efficient electrocatalytic water splitting

“…Similar electron interaction effects have been found in many composite structures, such as Fe(PO 3 ) 2 @Cu 3 P 111 and Co(PO 3 ) 2 @NPC/MoS 2 . 113 Further, Liu et al 118 synthesized a Mn-doped CoP/Ni(PO 3 ) 2 composite structure as a highly efficient overall water-splitting catalyst. They used the synergistic effect of Mn doping and a unique heterogeneous interface of phosphides/metaphosphates to reduce the HER kinetics barriers by electron redistribution and increasing the active sites, thus optimizing the adsorption free energies of the H atom.…”

An ultra-high mass-loading transition metal phosphide electrocatalyst for efficient water splitting and ultra-durable zinc–air batteries

“…[18][19][20][21][22] However, since the work medium for HER activity of a mono-metallic phosphide is incompatible with that for the OER activity in a specific pH electrolyte (either acidic or alkaline), achieving remarkable electrochemical performance for catalyzing the overall water splitting reaction in a monometallic phosphide-based symmetrical two-electrode cell setup is still challenging. 23 As a remedy to the above-mentioned difficulty, two approaches have been adopted to enhance the catalytic efficiency and durability of TMPs: 24 (i) tailoring TMPs with unique nanostructures and morphology (extrinsic catalytic activity), and more importantly, (ii) modulating the electronic configuration of TMPs through vacancy engineering or heteroatom doping (intrinsic catalytic activity). 25 Mixed metal phosphides exhibit higher catalytic activities than their single counterparts, revealing the positive synergy between the components.…”