A Superior and Stable Electrocatalytic Oxygen Evolution Reaction by One-Dimensional FeCoP Colloidal Nanostructures

Abstract

Transition metal phosphides (TMPs) are expected to be excellent electrocatalysts for oxygen evolution reaction (OER) because of their high stability, highly conducting metalloid nature, highly abundant constituting elements, and the ability to act as a precatalyst due to in situ surface-formed oxy-hydroxide species. Herein, a "one-pot" colloidal approach has been used to develop a rod-shaped one-dimensional non-noble metal FeCoP electrocatalyst, which exhibits an excellent OER activity with an exceptionally high current density of 950 mA cm −2 , a turnover frequency value of 7.43 s −1 , and a low Tafel slope value of 54 mV dec −1 . The FeCoP electrocatalyst affords OER ultralow overpotentials of 230 and 260 mV at current densities of 50 and 100 mA cm −2 , respectively, in 1.0 M KOH, and demonstrates a superior catalytic stability of 10,000 cycles and durability up to 60 h at 50 mA cm −2 . An insight into the superior and stable electrocatalytic OER performance by the FeCoP nanorods is obtained by extensive Xray photoelectron spectroscopy, X-ray diffraction, Raman and infrared spectroscopy, and cyclic voltammetry analyses for a mechanistic study. This reveals that a high number of electrocatalytically active sites enhance the oxygen evolution and kinetics by offering metal ion sites for utilitarian in situ surface formation and adsorption of *O, *OH, and *OOH reactive species for OER catalysis.

Robust and Promising Electrocatalytic Oxygen Evolution Reaction by Activated Cu–Co–B Amorphous Nanosheets

“…The deconvoluted spectra of Cu 2p in Figure f indicate the existence of only Cu 0 where Cu 2p 3/2 , 932.68 eV and Cu 2p 1/2 , 952.03 eV with Δ = 19.35 eV were assigned for Cu 0 . However, the deconvoluted XPS spectrum of Co 2p suggested that the cobalt was present in the elemental as well as in the oxidized form (Figure g). , The Co 0 is confirmed from the peaks at 778.56 eV (Co 2p 3/2 ) and 793.81 eV (Co 2p 1/2 ). The XPS peaks observed at 781.55 and 797.35 eV correspond to Co 2p 3/2 and Co 2p 1/2 , respectively, with a spin–orbit splitting of 15.80 eV, and two shakeup satellite peaks (785.78 and 803.07 eV) indicate the existence of Co 2+ /Co 3+ .…”

Incorporating NiCoP Cocatalyst into Hollow Rings of ZnCo-Metal–Organic Frameworks to Deliver Pt Cocatalyst like Visible Light Driven Hydrogen Evolution Activity

“…Further, the inset of Figure a shows the XRD pattern of as-prepared NCP nanocrystals where all the peaks resemble the standard Ni 2 P XRD pattern (JCPDS 71-2336) revealing a pure single-phase and crystalline form of NiCoP nanoparticles. , For the control experiments, the XRD patterns of Pt, FCP, Ni 2 P, and CoP NPs were also recorded and found to be in a pure phase (Figure S1). , The transmission-electron microscopy (TEM) images in Figure b and Figure S2a,b clearly exhibit the typical hollow ring morphology of the ZCM sample with an average size of ∼500 nm. These large sized novel hollow rings are formed from the self-assembly of the small sized hollow particles (nanoscale building blocks) with an average size ∼115 nm as shown in Figure c.…”

Robust and promising hydrogen and oxygen evolution reactions by a nanostructured bifunctional FeCoPd alloy electrocatalyst

“…The individual Fe (oxy)hydroxide and Co (oxy)hydroxide species or FeCo (oxy)hydroxide species have been commonly considered as active OER sites in an alkaline medium. 62–64 Now, taking into account the Tafel slope of the alkaline OER of FCP (47 mV dec −1 ), either [M* + OH − → M–*OH + e − ] or [M–*OOH + OH − → M* + O 2 + H 2 O + e − ] could be the rate-determining step (RDS) in the electron transfer reactions. 61,65 Recent theoretical calculations by Shinagawa et al pointed out that a low OER Tafel slope indicates a high coverage of M–*OH (>0.6), similar to that of the HER.…”

“…[62][63][64] Now, taking into account the Tafel slope of the alkaline OER of FCP (47 mV dec−1 ), either [M* + OH − / M-*OH + e − ] or [M-*OOH + OH − / M* + O 2 + H 2 O + e − ] could be the rate-determining step (RDS) in the electron transfer reactions. 61,65 Recent theoretical calculations by Shinagawa et al pointed out that a low OER Tafel slope indicates a high coverage of M-*OH (>0.6…”