Tiny Ir doping of sub-one-nanometer PtMn nanowires: highly active and stable catalysts for alcohol electrooxidation

Abstract

One-dimensional (1D) Pt-based nanowires (NWs) materials serve as efficient catalysts for alcohol electrocatalysis. However, precisely tailoring their size towards sub-one-nanometer scale has been verified as an effective method for enhancing electrocatalytic properties, which is rarely studied. In this work, we developed a one-pot simple yet efficient method for synthesizing a kind of sub-one-nanometer tiny Ir-doped PtMn NWs. The prepared PtMnIr NWs have an ultrathin structure with a mean diameter of around only 0.97 nm (about 3–5 atomic thickness), which display large surface areas and promote superficial Pt atom utilization. With the robust tiny Ir incorporation, the composition-optimized Pt₇₄Mn₂₁Ir₅ NWs showed enhanced mass activity, which was 1.51 and 1.53 times higher than those of non-Ir-doped Pt₇₉Mn₂₁ NWs for acidic ethanol oxidation reaction (EOR) and methanol oxidation reaction (MOR). Moreover, benefiting from the atom-level ultrathin size and well-tuned ligand effect from Ir to PtMn, the EOR/MOR mass activities of sub-nanometric Pt₇₄Mn₂₁Ir₅ NWs were 3.99- and 3.98-fold higher than those of Pt/C catalysts. More importantly, after successive EOR and MOR CV tests, the Ir-doped PtMn NWs still maintained 85.6% and 73.4% of the initial mass activity, which were much better than those of Pt₇₉Mn₂₁ NWs, Pt NWs, and Pt/C catalysts. This work could be extended to engineering other advanced materials with super sub-one-nanometer structure, which is beneficial for largely improving the catalytic performance.