We focus on the proton-conducting doped - barium zirconate, which has large proton conductivity at intermediate temperature. We found here a phenomenon that acid - etching of the doped barium zirconate in a solution having a specific pH leaves a porous structure on the surface, and demonstrated power generation of hydrogen fuel cell using electroless-plated Pd and Pt on the porously acid-etched electrolyte surface. The short circuit current density of the hydrogen fuel cell was about 430 mA/cm(2) at 600 degrees C using thick electrolyte of 500 mu m. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3606374] All rights reserved.