Nickel-Rich Phosphide (Ni₁₂P₅) Nanosheets Coupled with Oxidized Multiwalled Carbon Nanotubes for Oxygen Evolution

Abstract

Exploring and identifying efficient materials with operative active sites for electrochemical oxygen evolution reaction (OER) is of paramount importance for the future of energy conversion technologies like electrolyzers and fuel cells. Herein, we develop an effective strategy to couple physically distinct metal-rich nickel phosphide (Ni12P5) with mildly oxidized multiwall carbon nanotubes (O-MWCNTs) to boost the efficiency of OER. Ni12P5-O-MWCNTs outperforms O2 evolution activity in contrast to the parental materials, Ni12P5 and O-MWCNTs. Intriguingly, Ni12P5-O-MWCNTs shows an overpotential of 280 mV achieved at a current density of 10 mAcm–2. The hybrid, Ni12P5–O-MWCNTs demonstrates remarkable OER activity by the virtue of development of heterointerfaces in which the effective interaction between Ni12P5 and O-MWCNTs plays a crucial role. Moreover, we have analyzed the XPS and HR-TEM of Ni12P5-O-MWCNTs after the chronoamperometry study of OER to examine the structural changes due to the prolonged oxidation reaction. This post OER study enabled us to identify the precatalyst and the active functional groups present in O-MWCNTs. Our approach opens a path for fabricating hybrid catalytic systems with synergetic activity to facilitate optimized electrocatalytic activity.