Strained lattice platinum–palladium alloy nanowires for efficient electrocatalysis

Abstract

The ability to manipulate Pt-based alloy catalysts with controllable compositions and the type of surface facet is important for advancing direct alcohol fuel cells (DAFEs). Pt_xPd_100−x alloy nanowires (NWs) with tunable compositions and (111) facets show a Boerdijk–Coxeter helix type morphology and a slightly strained lattice, and were synthesized by a single-phase and surfactant-free method. X-ray diffraction results show that the alloy compositions can be used to tune the shrinking or expanding lattice parameter of Pt_xPd_100−x NWs. XPS analysis reveals that the alloy effect induced by d-band electron modulation changes the electronic structure and weakens the chemisorption strength of Pt by poisoning species and originally enhances the catalytic activity. The result that the electrocatalytic performance of Pt_xPd_100−x NWs for methanol and ethanol oxidation reactions reveals the high catalytic activity correlated with the exposed facet, strained lattice and alloy compositions. The dominant (111) facets of Pt₆₂Pd₃₈ NWs show the maximum catalytic activity, which is consistent with the XPS result. This finding will open a new way to design highly active and stable alloy nanocatalysts with controllable compositions for enhancing direct alcohol fuel cells.