One-Step Electrochemical Synthesis and Surface Reconstruction of NiCoP as an Electrocatalyst for Bifunctional Water Splitting

Abstract

We adopted a simple one-step electrochemical deposition to acquire an efficient nickel cobalt phosphorus (NiCoP) catalyst, which avoided the high temperature phosphatization engineering involved in the traditional synthesis method. The effects of electrolyte composition and deposition time on electrocatalytic performance were studied systematically. The as-prepared NiCoP achieved the lowest overpotential (η10 = 111 mV in the acidic condition and η10 = 120 mV in the alkaline condition) for the hydrogen evolution reaction (HER). Under 1 M KOH conditions, optimal oxygen evolution reaction (OER) activity (η10 = 276 mV) was also observed. Furthermore, the bifunctional NiCoP catalyst enabled a high-efficiency overall water-splitting by applying an external potential of 1.69 V. The surface valence and structural evolution of NiCoP samples with slowly decaying stability under alkaline conditions are revealed by XPS. The NiCoP is reconstructed into the Ni(Co)(OH)2 (for HER) and Ni(Co)OOH (for OER) on the surface with P element loss, acting as real “active sites”.

P-doped MOF-derived NiMo bimetallic sulfide used as a high efficiency electrocatalyst for oxygen evolution reaction

“…4D) consists of P-O (134.2 eV) and P-metal (133.4 eV) bonds. 39 While in the S 2p spectrum (Fig. 4E), peaks at 160.6, 161.9, and 168.5 eV correspond to S 2p 3/2 , S 2p 1/2 , and SO x groups, respectively.…”

“…), the deconvolution peaks around 858.7 and 877.2 eV are associated with the Ni 3+ oxidation state, and the other two peaks near 856.0 and 874.0 eV belong to Ni 2+ . 36,39 The energy spectrum of Mo 3d can be divided into four peaks (Fig. 4C).…”

Facile Electrochemical Synthesis of Bifunctional Needle-like Co-P Nanoarray for Efficient Overall Water Splitting

“…The OER active sites which are believed to be high-valence metal sites are exposed during the in situ electrochemical transformation under applied anodic potential [ 18 ]. Sheng et al reported that highly active NiCoP is reconstructed into Ni(Co)OOH as real active sites with P element loss during OER [ 19 ]. Additionally, the one-dimensional catalysts favor the acceleration of charge transfer and expose more active sites for enhancing OER and HER performance [ 20 ].…”

“…Figure S1: XRD pattern of electrodeposited Co-P-1; Table S1: HER activity comparison with other cobalt-based electrocatalysts; Table S2: OER activity comparison with other cobalt-based electrocatalysts; Figure S2: (a) HER and (b) OER polarization curves without iR -correction of these catalysts; Figure S3: (a) CV curves in the potential range of −0.5–0.5 V vs. RHE, and (b–d) CV curves of NF, Co(OH) 2 /NF, and Co-P-2/NF at various scan rates; Figure S4: Nyquist plots of these catalysts fitted with inserted equivalent circuit; Table S3: Parameters fitted with equivalent circuit model; Figure S5: (a) Initial SEM image and (b) SEM image after 24 h OER test of Co-P-1. References [ 16 , 19 , 41 , 42 , 43 , 44 , 45 , 46 ] are cited in the supplementary materials.…”

Magnetic Field-Assisted Electrodeposition of Fe3O4 Nanoparticles on Ni as Bifunctional Electrocatalyst for Overall Water Splitting

“…With rapidly developing industrialization, depletion of traditional energy sources, and deterioration of the ecological environment, hydrogen, as a green energy carrier with no pollution to the environment, is gradually being valued in modern society. Hydrogen production from electrolytic water is one of the possible options for the production of hydrogen. − One of the components of electrolytic hydrolysis is the production of hydrogen from electrolytic water. Two reactions usually involved in the decomposition of electrolytic water are OER occurring on the anode and HER on the cathode surface; the high overpotential and the slow kinetics of both reactions limit the use of overall water splitting in practical applications. − Therefore, catalysts are needed to reduce the overpotential of the reaction in the overall water splitting.…”