Trimetallic (Cobalt-Nickel-Copper) phosphates with cake ball-Like morphology for highly efficient oxygen evolution reaction

Abstract

Developing efficient, stable, and noble-metal-free electrocatalysts for the oxygen evolution reaction (OER) is both essential and challenging. This study presents a controlled synthesis approach for cobalt-nickel-copper trimetallic phosphide crystalline, derived from a trimetallic metal-organic framework (CoNiCu-MOF) precursor via low-temperature phosphorization. The morphology and structure of the synthesized materials were examined using XRD, Raman, FT-IR, FE-SEM, EDX, and TEM analyses. The OER performance was evaluated in a 1.0 M KOH solution. The cake ball-like CoNiCuP exhibited superior performance, with an overpotential of 228 mV, a Tafel slope of 41 mV $\mathit{de}{c}^{-1}$$\mathit{de}{c}^{-1}$, and a double-layer capacitance of 1.73 mF ${\mathit{cm}}^{-2}$${\mathit{cm}}^{-2}$. Additionally, the structure-maintained stability over 24 hours of operation. The significant enhancement in performance is attributed to the trimetallic framework with phosphorus and a crystalline porous design, which increases the effective surface area and enhances electron conductivity. These findings provide valuable insights for developing high-performance OER electrodes.