Platinum multicubes prepared by Ni²⁺-mediated shape evolution exhibit high electrocatalytic activity for oxygen reduction

Pt(100) facets are generally considered less active for the oxygen reduction reaction (ORR). Reported herein is a unique Pt-branched structure, a multicube, whose surface is mostly enclosed by {100} facets but contains high-index facets at the small junction area between the adjacent cubic components. The synthesis is accomplished by a Ni²⁺-mediated facet evolution from high-index {311} to {100} facets on the frameworks of multipods. Despite the high {100} facet coverage, the Pt multicubes exhibit impressive ORR activity in terms of half-wave potential and current density nearly to the level of the most active Pt-based catalysts, while the durability of catalysts is well retained. The facet evolution creates a set of samples with tunable ratios of high-index to low-index facets. The results reveal that the excellent ORR performance of Pt multicubes is a combined result of active sites by high-index facets and low resistance by flat surface. It is anticipated that this work will offer a new approach to facet-controlled synthesis and ORR catalysts design. Facet to facet: A Ni²⁺-mediated facet-evolution approach has been developed to synthesize novel Pt multicubes whose surface is mostly enclosed by {100} facets. The Pt multicubes exhibit very high electrocatalytic activity and remarkable durability in the oxygen reduction reaction because of the high-index facets at the junction between the cubic components. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.