The immersed effects of Ta and Zr compounds (Ta-CNO and Zr-CNO) on the activity of oxygen reduction reaction (ORR) have been investigated in the sulfuric acid. The concentration of Zr on Zr-CNO as higher than that of Pt on Pt black. The concentration of Ta on Ta-CNO was almost the same as that of Pt on Pt black in sulfuric acid. The catalytic activity of Zr-CNO for the ORR decreased with time. In contrast, the catalytic activity of Ta-CNO for the ORR was maintained up to 1050 h in the sulfuric acid. (C) 2012 Elsevier B.V. All rights reserved.