In recent years, shape control has received the most attention in the exploration of Pd nanocrystals (NCs). However, exploring an efficient approach for the systematic production of Pd NCs under similar reaction conditions still presents a significant challenge, which is significantly important to clearly explain the effectiveness of morphology on the catalytic activity of Pd NCs. We designed and accomplished a facile strategy for the morphology transformation between Pd nanosheets and Pd nanotetrahedra by simply controlling the reaction temperature. A growth mechanism was proposed based on TEM images of the time-dependent morphology evolution. The Pd nanosheets and Pd nanotetrahedra exhibit higher activity for the methanol oxidation reaction (MOR) and oxygen reduction reaction (ORR) compared with the benchmark Pd/C catalysts, and their activities are dependent on the morphology. In particular, Pd nanosheets show an increased activity by 3.81 (MOR) and 2.86 (ORR) times due to their large specific surface area and exposed facets. (C) 2016 Elsevier Inc. All rights reserved.