Ruthenium Complexes with a SWCNT-Modified Terpyridine Ligand as an Efficient Electrocatalyst for Oxygen Evolution Reaction

Electrocatalytic oxygen evolution reaction (OER) plays an important role in various renewable energy conversion and storage technologies. Ruthenium complexes with terpyridine (tpy) and bipyridine (bpy) as ligands are considered to be an important catalyst for OER electrocatalysis. Their catalytic performance is affected by substituent groups of the tpy (and bpy) ligands, and is often limited by low current density. Here, we report a Ru-polypyridine complex covalently anchored to single-walled carbon nanotubes (SWCNTs) via a tpy ligand to form a hybrid material of SWCNT-tpyRubpy. Electrocatalytic OER studies have shown that the covalent attachment of the Ru-polypyridine complexes to SWCNTs avoids noticeable molecular aggregations and increases the conductivity. Compared with that of the SWCNT-unattached complex, SWCNT-tpyRubpy exhibits a higher electrocatalytic OER activity with a low onset potential of 1.48 V (vs reversible hydrogen electrode) and a smaller Tafel slope of 109 mV dec(-1) in alkaline solution. Therefore, the CNT-hybridization is an effective method for the construction of advanced SWCNT-based Ru complex electrocatalysts and to understand their catalytic performance.