The Synergy of Tensile Strain and Ligand Effect in PtBi Nanorings for Boosting Electrocatalytic Alcohol Oxidation

As the best electrocatalysts for alcohol oxidation reactions in direct alcohol fuel cells (DAFCs), Pt-based nanomaterials still face the challenges of low utilization efficiency of Pt atoms and poor reaction kinetics. To address these issues, a self-etching strategy is developed to prepare PtBi nanorings (NRs) with abundant low-coordinated atoms and inhomogeneous tensile strain (approximate to 4%). The obtained PtBi NRs exhibit superior activity toward methanol oxidation reaction (MOR) and ethanol oxidation reaction (EOR) in alkaline media. Particularly, the mass activities of PtBi NRs for MOR and EOR are 9.4 and 8.5 times higher than those of commercial Pt/C, respectively, which are among the best in the reported Pt-based catalysts. The highly open structure of PtBi NRs is believed to provide plentiful catalytic active sites and increase the utilization of Pt atoms. Theoretical calculations show that the two important factors, i.e., adsorption energy with the key reaction intermediates and the energy barrier for the potential-determining step, are significantly optimized owing to the synergy of tensile strain and the ligand effect in PtBi NRs. This work offers a promising strategy for the rational design and preparation of highly efficient catalysts for DAFCs.

Automated summary

A self-etching strategy was developed to prepare PtBi nanorings with abundant low-coordinated atoms and inhomogeneous tensile strain. The PtBi nanorings showed superior activity towards methanol and ethanol oxidation reactions in alkaline media. The mass activities of the PtBi nanorings for methanol and ethanol oxidation reactions were 9.4 and 8.5 times higher than that of commercial Pt/C, respectively. The highly open structure of the PtBi nanorings provided plentiful catalytic active sites and increased the utilization of Pt atoms. The synergy of tensile strain and the ligand effect in PtBi nanorings optimized the adsorption energy and energy barrier of the key reaction intermediates. This work offers a promising strategy for the rational design and preparation of highly efficient catalysts for direct alcohol fuel cells.