Systems and methods for preparing electrocatalysts are disclosed. The system includes a high temperature synthesis device for preparing an array of electrocatalysts as electrolytic surfaces of working electrodes. At least a portion of the electrolytic surfaces are defined by different materials. The device includes a plurality of openings for receiving the array of working electrodes and a mask having a plurality of openings configured for exposing at least a portion of each of the working electrodes for forming the electrolytic surfaces thereon.