The Scalable Solid-State Synthesis of a Ni5P4/Ni2P–FeNi Alloy Encapsulated into a Hierarchical Porous Carbon Framework for Efficient Oxygen Evolution Reactions

Abstract

The exploration of high-performance and low-cost electrocatalysts towards the oxygen evolution reaction (OER) is essential for large-scale water/seawater splitting. Herein, we develop a strategy involving the in situ generation of a template and pore-former to encapsulate a Ni5P4/Ni2P heterojunction and dispersive FeNi alloy hybrid particles into a three-dimensional hierarchical porous graphitic carbon framework (labeled as Ni5P4/Ni2P–FeNi@C) via a room-temperature solid-state grinding and sodium-carbonate-assisted pyrolysis method. The synergistic effect of the components and the architecture provides a large surface area with a sufficient number of active sites and a hierarchical porous pathway for efficient electron transfer and mass diffusion. Furthermore, a graphitic carbon coating layer restrains the corrosion of alloy particles to boost the long-term durability of the catalyst. Consequently, the Ni5P4/Ni2P–FeNi@C catalyst exhibits extraordinary OER activity with a low overpotential of 242 mV (10 mA cm−2), outperforming the commercial RuO2 catalyst in 1 M KOH. Meanwhile, a scale-up of the Ni5P4/Ni2P–FeNi@C catalyst created by a ball-milling method displays a similar level of activity to the above grinding method. In 1 M KOH + seawater electrolyte, Ni5P4/Ni2P–FeNi@C also displays excellent stability; it can continuously operate for 160 h with a negligible potential increase of 2 mV. This work may provide a new avenue for facile mass production of an efficient electrocatalyst for water/seawater splitting and diverse other applications.

Construction of Core–Shell CoMoO4@γ-FeOOH Nanosheets for Efficient Oxygen Evolution Reaction

“…Wang's group has recently reported that the core-shell structure of Au@NiCo 2 S 4 core-shell NPs could result in a higher proportion of high-valance Ni/Co cations and improve its electronic conductivity, which collectively enhances its OER catalytic performance [20]. In addition, a great number of the heterostructures have also been fabricated for an improved electronical performance, such as CoP/FeP 4 [21], Co 9 S 8 /CoO/NC [22], CoFeS 2 @CoS 2 [23], Ni-P-S@FeOOH/CC [24], Ni 5 P 4 /Ni 2 P-FeNi [25], and MnO-OVs/NCNTs [26].…”

Chemical Transformation Induced Core–Shell Ni2P@Fe2P Heterostructures toward Efficient Electrocatalytic Oxygen Evolution

“…Until now, considerable efforts have been made to explore Earth-abundant and highefficiency transition metal-based OER catalysts, including layered double hydroxides (LDHs) [4], metal oxides [5], phosphides [6], selenides [7], sulfides [8], nitrides [9], and so on. Among them, transition-metal phosphides (TMPs) have been considered as promising candidates for alkaline OER catalysis because of their good electrical conductivity with metalloid characteristics and remarkable durability in working conditions with strong alkaline electrolytes and theoretically outstanding electrochemical catalytic behaviors [10][11][12][13][14].…”