MOF-Directed Fabrication of Nickel/Cobalt Bimetallic Phosphides as Robust Electrocatalyst for Oxygen Evolution Reaction

Abstract

The construction of efficient and stable non-noble metal electrocatalysts for oxygen evolution reaction (OER) is a major challenge via water splitting to make H 2 fuel. Herein, we report the hybrids of NiCo bimetallic phosphides (denoted as NixCoy-P) through a one-step phosphidation strategy derived from nanosheets NiCo metal-organic frameworks (NixCoy-BDC). The unique hierarchical porous structure, heterogeneous (Ni 2 P and Co 2 P) composition and carbon framework of the NixCoy-P hybrids were characterized by scanning electron microscope, X-ray diffraction and transmission electron microscope, which endowed handy ion diffusion path, synergistically active sites and high conductivity for OER. The as-fabricated Ni1Co1-P catalyst exhibited more excellent OER activity than other phosphides (Ni-P, Ni3Co1-P, Ni1Co3-P and Co-P). More remarkably, the Ni1Co1-P supported on Ni foam (NF) exhibits low overpotential (η 35 ) of 300 mV at a current density of 35 mA cm −2 , small Tafel slope of 71 mV dec −1 and excellent stability for OER in 1.0 M KOH solution. This work provides a general strategy to design more efficient multi-metallic component OER electrocatalysts.

Recent advancements in MOF‐ based catalysts for applications in electrochemical and photoelectrochemical water splitting: A review

“…Phosphating of Ni-Co MOF resulted in Ni-Co bimetallic phosphides (Ni x Co y -P) possessing a unique hierarchical porous structure. 133 Yujie et al devised a strategy where they calcined the cobalt-doped MOF prepared by solvothermal synthesis at different temperature such as 550, 600, and 700 to synthesize a carbonized derivative of Co-based MOF for OER. 134 Wan et al prepared a three-dimensional rhombus like structure of iron-dysprosium oxide composite.…”

“…Shuai et al also employed nanosheets of bimetallic Ni‐Co MOFs (Ni x Co y ‐BDC) to synthesize effective and stable electrocatalysts for OER. Phosphating of Ni‐Co MOF resulted in Ni‐Co bimetallic phosphides (Ni x Co y ‐P) possessing a unique hierarchical porous structure 133 . Yujie et al devised a strategy where they calcined the cobalt‐doped MOF prepared by solvothermal synthesis at different temperature such as 550, 600, and 700 to synthesize a carbonized derivative of Co‐based MOF for OER 134 .…”

“…This work provides a general strategy to design more efficient multi-metallic component OER electrocatalysts. 133 MOF (Fe-Co 3 ) 550 was obtained from cobalt-doped NH 2 -MIL-53(Fe) via direct carbonization by Han et al and was tested for OER. Spindle shaped (Fe-Co 3 ) 550 showed the best response due to structural stability.…”

Metal‐organic frameworks‐derived novel nanostructured electrocatalysts for oxygen evolution reaction

“…In Figure 8C, the coexistence of Ni 2 P and CoP nanoparticles was indicated by the high‐resolution transmission electron microscopy (HRTEM) analysis. Compared with the mechanically mixed Ni 2 P and CoP, the bimetallic Ni–Co–P system showcased intensive electrocatalytic activity in both OER and HER, in light of the strong synergistic effects, which called for merely an overpotential of 320 mV to realize a current density of 10 mA/cm 2 in OER 91 . As a result, it underscored the significance of interfaces in the analysis of materials.…”

“…Compared with the mechanically mixed Ni 2 P and CoP, the bimetallic Ni-Co-P system showcased intensive electrocatalytic activity in both OER and HER, in light of the strong synergistic effects, which called for merely an overpotential of 320 mV to realize a current density of 10 mA/cm 2 in OER. 91 As a result, it underscored the significance of interfaces in the analysis of materials. The utilization of rationally controlled formation of interfaces is instrumental for the design and fabrication of bicomponent as well as multicomponent electrocatalysts.…”