Interface Engineering of Nickel Hexacyanoferrate Anchored on Covalent Triazine Framework-Coated Carbon Nanotubes for Oxygen Evolution

Abstract

Developing electrocatalysts of remarkable potency, rapid charge transfer, and lasting durability is crucial for improving electrocatalytic performance toward the oxygen evolution reaction (OER). Here, a nickel hexacyanoferrate-anchored covalent triazine framework-coated carbon nanotube composite catalyst (NiHCF@CTF/CNT) was fabricated through a one-step hydrothermal strategy. In this core−shell hierarchical architecture, the CNT serves as a conductive inner core, CTF provides a nitrogen-rich confined interface and anchoring sites, and NiHCF is loaded on the outer surface as a Ni/Fe bimetallic active precursor. Benefiting from optimized interfacial coupling and more accessible active sites, NiHCF@CTF/CNT exhibits excellent OER performance in 1 M KOH, requiring only 275 mV to deliver 10 mA cm−2, with a low Tafel slope of 42.97 mV dec−1, while maintaining stable operation for 300 h. Combined experimental and theoretical analyses reveal favorable electronic structure reconstruction of the surface Ni/Fe sites, which optimizes intermediate adsorption and lowers the reaction energy barrier. This study provides a viable strategy for developing high-durability composite OER electrocatalysts.