In situ construction of surface defects of carbon-doped ternary cobalt-nickel-iron phosphide nanocubes for efficient overall water splitting

Abstract

The ternary cobalt-nickel-iron phosphide nanocubes (P-Co 0.9 Ni 0.9 Fe 1.2 NCs) with high intrinsic activity, conductivity, defect concentration and optimized ratio have been realized through a facile phosphorization treatment using ternary cobalt-nickel-iron nanocubes of Prussian blue analogs (PBA) as a precursor. The scanning electron microscopy and transmission electron microscopy results show that the P-Co 0.9 Ni 0.9 Fe 1.2 NCs maintain a cubic structure with a rough surface, implying the rich surface defects as exposed active sites. The thermal phosphorization of the ternary PBA precursor not only provids carbon doping but also leads to the in situ construction of surface defects on the NCs. The carbon doping from the PBA precursor lowers the charge transfer resistance and optimizes the electronic transformation. The synergistic effect among the ternary metal ions and rich defects contributes to the enhanced electrocatalytic performance. The P-Co 0.9 Ni 0.9 Fe 1.2 NCs achieve low overpotentials of −200.7 and 273.1 mV at a current density of 10 mA cm −2 for the hydrogen evolution reaction and the oxygen evolution reaction, respectively. The potential of overall water splitting reaches 1.52 V at a current density of 10 mA cm −2. The longterm stability of the electrocatalysts was also evaluated. This work provides a facile method to design efficient transitionmetal-based bifunctional electrocatalysts for overall water splitting.

Recent Advances in Non‐Precious Metal‐Based Electrodes for Alkaline Water Electrolysis

“…In a general approach, such materials based on the similarity of electronic transition states could be anticipated as efficient catalyst for HER activity . Among the many, the P‐Co 0.9 Ni 0.9 Fe 1.2 nanocubes with rough morphology were reported to be an efficient catalyst with an over‐potential of −200.7 mV at current density of 10 mA cm −2 . Similarly, Liu et al.…”

“…[43] Among the many, the P-Co 0.9 Ni 0.9 Fe 1.2 nanocubes with rough morphology were reported to be an efficient catalyst with an over-potential of À 200.7 mV at current density of 10 mA cm À 2 . [44] Similarly, Liu et al described the relationship with exposed surface facets with catalytic activity. In the reported approach, the Ni 2 P (001) surfaces with exposed Ni and P sites exhibited relatively superior HER catalytic activity as estimated using density functional theory.…”

Hollow cobalt-nickel phosphide nanocages for efficient electrochemical overall water splitting

“…In recent years, transition-metal oxides and corresponding transition metal phosphides [21][22][23][24], sulfides [25,26], nitrides [27,28], and selenides [29][30][31] have been extensively studied as non-precious bi-functional electrocatalysts for overall water-splitting. In particular, transition metal phosphides, especially bimetallic transition metal phosphides have attracted significant attentions as bi-functional electrocatalysts for water-splitting owing to their remarkably enhanced catalytic activities [32,33].…”

One-dimensional CO9S8-V3S4 heterojunctions as bifunctional electrocatalysts for highly efficient overall water splitting

“…Electrocatalytic water splitting to produce hydrogen (H 2 ) with renewable energies input is envisioned as an attractive route to tackle energy shortage and environ-mental pollution caused by massive burning of traditional fossil fuels [1]. It involves two half reactions of the cathodic hydrogen evolution reaction (HER) and the anodic oxygen evolution reaction (OER) [2][3][4][5]. However, the electrocatalytic water splitting is difficult to trigger due to the sluggish kinetics of both two half-reactions [6][7][8][9].…”