Platinum porous nanosheets with high surface distortion and Pt utilization for enhanced oxygen reduction catalysis

Abstract

Unlike the well-established shape/composition control, surface distortion is a newly emerged yet largely unexplored nanosurface engineering for boosting electrocatalysis. Tapping into the novel electrocatalysts for taking full use of the distortion effect is therefore of importance but remains a formidable challenge. Here, an approach to designing highly distorted porous Pt nanosheets (NSs) by electrochemical erosion of ultrathin PtTe2 NSs is reported. The inherent ultrathin feature and massive leaching of Te have conspired to produce a highly distorted structure. As a result, the generated Pt NSs exhibit a much-enhanced oxygen reduction reaction (ORR) mass and specific activity of 2.07 A mgPt −1 and 3.1 mA cm−2 at 0.90 V versus reversible hydrogen electrode, 9.8 and 10.7 times higher than those of commercial Pt/C. The highly distorted Pt NSs can endure 30 000 cycles with negligible activity decay and structure variation. Density functional theory calculations reveal that the electrochemical corrosion induced nanopores, boundaries, and vacancies consist of Pt sites with substantially low coordination numbers deviating from the one of pristine Pt (111) surface. These Pt sites actively act as electron-depleting centers for highly efficient electron transfer toward the adsorbing O-species. This study opens a new design for fully using the distortion effect to promote ORR performance and beyond.