Oxygen reduction reaction (ORR) electrocatalysts with high activity, extended durability and lower cost are needed for proton exchange membrane fuel cells (PEMFCs). Compared with conventional nanoparticles, nanosheets composed of atomic-thin two-dimensional (2D) layers offer a higher relative concentration of catalytically active (111) surfaces.  In contrast to many approaches that have investigated graphene-supported Pt ORR catalysts, we have explored Pt supported on Ni(OH)₂  nanosheets (i.e. Ni(OH)₂@Pt) for enabling high activity ORR electrocatalysts.  Synthesis conditions were controlled to obtain Ni(OH)₂  nanosheets with controlled sizes, phase, and aggregation.  Temperature/atmosphere treatments were found to significantly affect the structure and morphology of the nanosheets.  The effect of changing the Pt shell composition on the Ni(OH)₂ nanosheets on the ORR activity was evaluated. The nanosheet structure and morphology with determined using x-ray diffraction and scanning electron microscopy, and the ORR activity was determined from rotating disc electrode experiments.  Our initial results have shown that Ni(OH)₂@Pt nanosheets provide significantly higher catalytic activities compared with Pt/C. The ability to control the structure and properties of 2D transition metal oxide nanosheets provides a route to develop electrocatalysts with high activity, extended durability, and lower cost.